Note: Descriptions are shown in the official language in which they were submitted.
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1 Sport Monitoring System for Determining Airtime, Speed, Power Absorbed and
other
2 Factors such as Drop Distance
3
4 Field of the Invention
. 5 The invention relates generally to monitoring and quantifying sport
movement (associated
6 either with the person or with the vehicle used or ridden by the person),
including the specific
7 parameters of "air" time, power, speed, and drop distance. The invention
also has "gaming"
8 aspects for connecting users across the Internet. The invention is
particularly useful in sporting
9 activities such as skiing, snowboarding, mountain biking, wind-surfing,
skate-boarding, roller-
o blading, kayaking, racing, and running, in which sporting persons expend
energy, catch "air",
11 move at varying speeds, and perform jumps.
12
13 Background of the Invention
t4 It is well known that many skiers enjoy high speeds and jumping motions
while traveling
15 down the slope. High speeds refer to the greater and greater velocities
which skiers attempt in
16 navigating the slope successfully (and sometimes unsuccessfully). The
jumping motions, on the
17 other hand, include movements which loft the skier into the air. Generally,
the greater the skier's
1 s speed, the higher the skier's loft into the air.
19 The interest in high speed skiing is apparent simply by observing the
velocity of skiers
2o descending the mountain. The interest in the loft motion is less apparent;
although it is known that
2 ~ certain enthusiastic snowboarders regularly exclaim "let's catch some air"
and other assorted
22 remarks when referring to the amount and altitude of the lofting motion.
23 The sensations of speed and jumping are also readily achieved in other
sporting activities,
2~ such as in mountain biking, skating, roller-blading, wind-surFng, and skate-
boarding. Many
25 mountain bikers and roller-bladers, like the aforementioned skiers, also
crave greater speeds and
26 "air" time.
27 However, persons in such sporting activities only have a qualitative sense
as to speed and
28 loft or "air" time. For example, a typical snowboarder might regularly
exclaim after a jump that
29 she "caught" some "big sky," "big air" or "phat air" without ever
quantitatively knowing how
3o much time really elapsed in the air.
31 Speed or velocity also remain unquantified. Generally, a person such as a
skier can only
32 assess whether they went "fast", "slow" or "average", based on their
perception of motion and
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1 speed (which can be grossly different from actual speed such as measured
with a speedometer or
2 radar gun).
3 There are also other factors that sport persons sometimes assess
qualitatively. For example,
4 suppose a snowboarder skis a double-diamond ski slope while a friend skis a
green, easy slope.
When they both reach the bottom, the "double-diamond" snowboarder will have
expended more
6 energy than the other, generally, and will have worked up a sweat; while the
"green" snowboarder
7 will have had a relatively inactive ride down the slope. Currently, they
cannot quantitatively
8 compare how rough their journeys were relative to one another.
9
Obiects of the Invention
> > It is, accordingly, an object of the invention to provide systems and
methods for
12 determining "air" time associated with sport movements.
13 It is another object of the invention to provide systems and methods for
determining the
14 speed of participants and/or vehicles associated with sport movements.
It is yet another object of the invention to provide improvements to sporting
vehicles
16 which are ridden by sporting participants, and which provide a
determination of speed, airtime,
17 drop distance and/or power of the vehicle.
i8 Still another object of the invention is to provide systems and methods for
determining the
19 amount of "power" or energy absorbed by a person during sporting
activities. One specific object
is to provide a gauge of energy spent by a sporting participant as compared to
others in the same
2 t sport, to provide a quantitative comparison between two or more
participants.
22 Yet another object of the invention is to provide the "drop distance"
associated with a
23 jump; and particularly the drop distance which occurs within the "airtime".
24 Still another object of the invention is to provide a gaming system to
quantitatively
compare airtime, drop distance, power, and/or speed between several
participants, regardless of
26 their location.
27 These and other objects of the invention will become apparent in the
description which
2s follows.
29
Summary of the Invention
3 ~ As discussed herein, "air" or "loft" time (or "airtime") refer to the time
spent off the
32 ground during a sporting movement. For example, airtime according to the
invention can include a
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1 snowboarder catching air off of a mogul or a ledge. Typically, airtime is
greater than one-half (or
2 one-third) second and less than six seconds. In "extreme" sporting events,
the maximum airtime
3 can increase up to about ten seconds or fifteen seconds.
In most cases, it is useful to specify the lower and upper limits of airtime -
e.g., from one
' 5 second to five seconds - so as to reduce processing requirements and to
logic out false airtime
6 data. More particularly, the following description provides several
techniques and methods for
'7 determining airtime. One technique, for example, monitors the vibration of
the user's vehicle
s (e.g., a ski or snowboard) moving on the ground; and senses when the
vibration is greatly reduced,
9 indicating that the vehicle is off the ground. However, when such a user
stands in line for the
1 o chair-lift, she might remain motionless for thirty seconds or more. By
restricting the upper limit to
> > five seconds, a system of the invention can be made to ignore conditions
such as standing in line.
12 Similarly, when a user walks slowly, there are cyclical periods of
relatively small vibration (e.g.,
~ 3 when the user lifts his foot off the ground). Therefore, a lower limit of
one-half second or one
second are appropriate; so that any detected "airtime" that falls below that
lower limit is ignored
~ 5 and not stored.
16 In another aspect of the invention, the measurement of airtime is used to
quantify the
n7 efficiency by which a person or sport vehicle remain on the ground. By way
of example, speed
l s skiers desire to remain on the ground; and the invention thus provides a
system which monitors
19 the person and/or vehicle (e.g., the slalom ski) to detect airtime. This
information is fed back to the
2o person (in real time or in connection with a later review of video) so that
he or she can improve
2 ~ their posture to reduce unwanted airtime. In such applications, airtime is
typically less than about
22 three or four seconds; and the lower limit is essentially zero {that is,
providing miniscule airtime
23 data can be appropriate for training purposes).
24 As used herein, "power" refers to the amount of energy expended by a person
or vehicle
25 during a sporting activity, typically over a period such as one ski run.
The following description
26 provides several systems, techniques and methods for determining power.
Power need not
2'7 correspond to actual energy units; but does provide a measure of energy
expended by the person or
28 vehicle as compared to other persons and vehicles in the same sporting
activity. Power can relate
29 be used to quantify "bragging rights" between sport enthusiasts: e.g., one
user can quantify that he
3o expended more energy, or received more "punishment", as compared to a
friend. Power can refer
31 to the amount of "G's" absorbed during a given period of activity. Power is
typically quantified
~. 32 over a period that is selectable by the user. For example, power can be
determined over successive
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1 one-second periods, or successive five second periods, or successive one
minute periods, or
2 successive five minute periods, or other periods. Power can also be measured
over a manually
3 selected period. For example, two snowboarders can initialize the period at
the beginning of a run
4 down a ski slope and can stop their period at the end of the run.
"Speed" refers the magnitude of velocity as measured during a sport activity.
Speed
generally refers to the forward direction of the moving sportsman.
7 "Drop distance" refers to the height above the ground as experienced by a
user or vehicle
8 during a sport activity. Drop distance preferably corresponds to a measured
airtime period. For
9 example, a snowboarder who takes a jump off of a ledge might drop thirty
feet (drop distance) in
three seconds (airtime). Drop distance can also specifically refer to maximum
height above the
11 ground for a given jump (for example, a user on a flat surface can first
launch upwards off a jump
12 and return to the same level but experience a five foot drop distance).
13 The invention thus provides systems and methods for quantifying airtime,
power, speed
t 4 and/or drop distance to quantify a user's sport movement within one or
more of the following
activities: skiing, snowboarding, wind-surfing, skate-boarding, roller-
blading, kayaking, white
16 water racing, water skiing, wake-boarding, surfing, racing, running, and
mountain biking. The
invention can also be used to quantify the performance of vehicles upon which
users ride, e.g., a
18 snowboard or ski or mountain bike.
19 The following U.S. patents provide useful background for the invention and
are herein
2o incorporated by reference: U.S. Patent No. 5,343,445; U.S. Patent No.
4,371,945; U.S. Patent No.
21 4,757,714; U.S. Patent No. 4,089,057; U.S. Patent No. 4,722,222; U.S.
Patent No. 5,452,269; U.S.
22 Patent No. 3,978,725; and U.S. Patent No. 5,295,085.
23 In one aspect, the invention provides a sensing unit which includes a
controller subsystem
24 connected with one or more of the following sensors (each of which is
described herein): an
airtime sensor, a speed sensor, a power sensor, and a drop distance sensor.
The controller
26 subsystem includes a microprocessor or microcontroller and can include
preamplifiers and A/D
27 converters to interface with the sensors) (alternatively, the sensor
contains such circuitry). The
28 controller subsystem can further include logic circuitry and/or software
modules to logic out
29 unwanted data from the sensors (e.g., airtime data that does not correspond
to reasonable loft
3o times). Preferably, the controller subsystem also includes digital memory
to store parameters for
31 the sensors and to store data such as power, airtime, speed and drop
distance (collectively
32 "performance data") for later retrieval. A battery typically is used to
power the controller
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1 subsystem. The battery can also be used for the sensors, if required.
However, one preferred sensor
2 which can function for any of the sensors is the piezoelectric foils such as
made from AMP
. 3 SENSORS'~"~. These foils do not require power and rather generate a
voltage in response to input
forces such as sound. A display can be integrated with the sensing unit to
provide direct feedback
5 to the performance data. In one aspect, a user interface is also integrated
with the sensing unit to
6 provide user control of the sensing unit, e.g., to include an ON/OFF switch
and buttons to select
7 for acquisition or display of certain performance data.
8 The sensing unit of one aspect is a stand-alone unit, and thus includes a
housing. The
9 stand-alone unit thus includes a housing that is rugged to survive the
rigorous sporting activity.
Preferably, the housing provides a universal interface which permits mounting
of the unit to a
1 ~ variety of vehicle platforms, e.g., onto a ski, snowboard, mountain bike,
windsurfer, roller blades,
~ 2 etc. The universal interface is preferably a conformal surface which
conveniently permits
13 mounting of the sensing unit to a plurality of surfaces, e.g., a flat
surface such as a snowboard, and
a round bar such as on a mountain bike.
Alternatively, the sensing unit can be integrated into objects already
associated with the
sporting activity. In one aspect, the sensing unit is integrated into the ski
boot or other boot. In
n7 another aspect, the sensing unit is integrated into the binding for a ski
boot or snowboarder boot.
18 In still another aspect, the sensing unit is integrated into a ski,
snowboard, mountain bike,
19 windsurfer, windsurfer mast, roller blade boot, skate-board, kayak, or
other sport vehicle.
2o Collectively, the sport objects such as the ski boot and the variety of
sport vehicles are denoted as
2 ~ "sport implements". Accordingly, when the sensing unit is not "stand
alone", the housing which
22 integrates the controller subsystem with one or more sensors and battery
can be made from the
23 material of the sport implements, in whole or in part, such that the
sensing unit becomes integral
24 with the sport implement. The universal interface is not therefore desired
in this aspect.
In one preferred aspect, the sensing unit provides for the measurement of
power entirely
26 within a watch. Manufacturers such as CASIO'~"'', TIMEX'"'', SEIKOz'''',
FILA'~"~, and SWATCH'"'
27 make sport wrist-watches with certain digital electronics disposed therein.
In accord with the
2s invention, power measurement capability is added within such a watch so
that "power" data can
29 be provided to sport enthusiasts in all sports, e.g., volleyball, soccer,
football, karate, and similar
3o common sports.
31 In one preferred aspect, the performance data is transmitted via
radiofrequencies (or other
32 data transfer technique, including infrared light or an inductively-coupled
electronics) from the
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1 sensing unit to a data unit which is ergonomically compatible with the user.
Accordingly, the
2 sensing unit in this aspect does not require a display as performance data
is made available to the
3 user through the data unit. For example, the data unit of one aspect is a
watch that the user wears
4 on her wrist. The data unit can alternatively be made into a "pager-like"
module such as known
fully in the art (MOTOROLA is one well-known manufacturer that makes pager
modules). In
6 either case, the sensing unit and the data unit cooperate to provide a
complete system for the user.
7 The data unit can take other forms, in other aspects. For example, the
performance data can
s be transmitted directly to a radio receiver connected to headphones worn by
the user or to a small
9 speaker worn in the user's ear. The radio receiver is for example similar to
the SONY°
1 o WALKMAN°, used by plenty of sports enthusiasts. In accord with the
invention, the sensing unit
transmits performance data directly into to the receiver so that the user can
listen - in real time- to
12 the results of his sports performance. Specifically, the radio receiver
includes a data conversion
13 unit which responds to the receipt of performance data from the sensing
unit and which converts
~ 4 the performance data into sound, via the headphones, so that the user
listens to the performance
data. After a jump, for example, the data conversion unit transmits airtime
and drop distance data
16 to the user so that the user hears "1.8 seconds of air, 5 feet drop
distance".
17 The data unit can also be made into the pole of a skier, such that a
display at the end of the
I s pole provides performance data to the user.
t s In still another aspect, the data unit is not required. Rather,
performance data is transmitted
2o such as by RF directly from the sensing unit to a base station associated
with the sporting area. For
2~ example, the base station can be a computer in the lodge of a ski area. The
sensing unit of this
22 aspect transmits performance data tagged to a particular user to the base
station where
23 performance data from all users is collated, stored, compared and/or
printed to various purposes.
24 Preferably, the base station includes processing capability and storage
whereby performance data
can be assessed and processed. For example, a user at the end of the day can
receive a print-out (or
26 computer disk) of his performance data; and the report can include a
comparison to other
27 performers within the sporting activity. If the activity is snowboarding,
for example, the user can
28 see his performance data as compared to other snowboarders on a particular
mountain.
29 Performance data can also be catalogued according to age, date, and
performance data type (e.g.,
3o airtime, power, speed and/or drop distance).
31 In one aspect, the base station augments the sensing units by providing
processing power
32 to calculate and quantify the performance data. For example, in this
aspect, raw sensor data such
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1 as from a microphone is transmitted from the sensing unit to the base
station, which thereafter
2 calculates the appropriate performance data. The sensing unit "tags" the
transmitted data so as to
. 3 identify a particular user. The base station of this aspect then
calculates and stores the appropriate
4 performance data for that particular user.
The base station can further include a Web Site server that connects the base
station to
6 other such base stations via the Internet so that performance data from
users can be collated,
7 stored, compared and/or printed for a variety of purposes. One or more
servers thus function as the
8 primary servers from which users can obtain their performance data from
their own computers, via
9 the Internet (or via a LAN or WAN). In one aspect, the primary servers also
function as a gaming
o network where performance data from all users is integrated in a
recreational manner, and made
11 available to all or selected users.
12 In one aspect, sensing units (or sensing units and data units) are thus
rented by the owners
13 of a particular sporting area (e.g., a ski area) such as in connection with
the rental of a snowboard,
4 or even as a stand-alone device that mounts to the user's board. The sensing
unit can provide real-
time performance data to the user, via a connected display or via a data unit.
Alternatively, the
6 sensing unit transmits data to the rental facility (or to the base station
connected via a LAN to the
17 rental facility) so that the user retrieves his or her performance data at
the end of the day.
18 In one aspect of the invention, performance data is sensed through one or
more sensors
i ~ connected with the sensing unit. It is not desirable to provide all
performance data for all
2o sporting activities. For example, for white water rafting or kayaking, a
"power sensing unit" is
2t useful - to quantify the roughness of the ride - but airtime data is
practically useless since
22 typically such vehicles do not catch air. In addition, for any given system
(i.e., sensing units or
23 sensing units and data units combined), more sensors add cost and require
added processing
24 capability, requiring more power draw and reducing battery lifetime.
Therefore, certain aspects
of the invention provide sensing units that provide only that portion of the
performance data
26 that is useful and/or desirable for a given sporting function, such as the
following sensing units:
27
28 Airtime Sensing Unit
29 One sensing unit of the invention measures "air" time, i.e. the time a
person such as a
~~ 3o snowboarder or skier is off the ground during a jump. This airtime
sensing unit is preferably
., 31 battery-powered and includes a microprocessor (or microcontoller). The
airtime sensing unit
32 either connects to a data unit; or can include a iow-powered liquid crystal
display (LCD) to
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communicate the "air" time to the user. The components for this airtime
sensing unit can
2 include one or more microphones or accelerometers to detect vibration (i.e.,
caused by friction
3 and scraping along the ground) of the user's vehicle along the ground, so
that "airtime" is
4 measured when an appropriate absence of vibration is detected. Preferably,
the electronics for
the airtime sensing unit are conveniently packaged within a single integrated
circuit such as an
6 ASIC. A digital memory stores airtime data; or alternatively, the airtime
sensing unit transmits
'7 airtime performance data to a data unit or to a base station.
8 The airtime sensing unit preferably provides several facets of airtime
performance data,
9 such as any of the following information data and features:
( 1 ) Total and peak air time for the day. In this aspect, the airtime sensing
unit provides at
1 I least the peak airtime for the day. The sensing unit can also integrate
all airtimes for the day to
~ 2 provide a total airtime.
13 (2) Total dead time for the day. In this aspect, the airtime sensing unit
includes an internal
14 clock that also integrates the time for which no sporting activity is made
such as over a given
day. For example, dead time can include that time within which the user is. at
the bar, rather
16 than skiing.
17 (3) Air time for any particular jump. As discussed above, briefly, this
aspect of the airtime
1 g sensing unit provides substantially real-time data to the user such as the
amount of airtime for a
19 recent jump. By way of example, a data unit with headphones, in one aspect,
provide this data
2o immediately after the jump. Alternatively, the airtime data for the jump is
stored within
21 memory (either within the data unit or in the sensing unit) so that the
user can retrieve the data
22 at his convenience. For example, data for a particular jump can be
retrieved from a watch data
23 unit on the chairlift after a particular run which included at least one
jump. In this manner, the
24 user can have substantially real-time feedback for the airtime event.
(4) Successive jump records of air time. In this aspect, jump records over a
selected period
26 (e.g., one day) are stored in memory either in the data unit or in the
airtime sensing unit. These
27 airtime "records" are retrieved from the memory at the user's convenience.
The system can
28 also simply store such records until the memory is full, at which time the
oldest record is over-
29 written to provide room for newer airtime data. The data can also be
transmitted to a base
3o station which includes its own memory storage for retrieval by the user.
31 (5) Averages and totals, selectable by the user. In this aspect, the
sensing unit or data unit
32 (or the base station) saves airtime data within memory for later retrieval
by the user. The period
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for which the data is valid is preferably selectable by the user. The data of
this aspect includes
2 airtime averages, over that period, or airtime totals, corresponding to the
summation of those
3 airtimes over that period.
4 (6) Rankings of records. In this aspect, the sensing unit or data unit (or
base station) saves
airtime data within memory for later retrieval by the user. For example, the
user obtains airtime
6 data through the data unit while on the chairlift or later obtains the data
in print-out form at the
7 base station, or a combination of the two. The period for which the data is
valid is preferably
s selectable by the user. The data of this aspect includes airtime records,
over that period, and the
9 airtime records are preferably ranked by airtime size, the biggest "air" to
the smallest.
o (7) Logic to reject activities which represents false "air" time. As
discussed above, the
11 preferred airtime sensing unit includes logic circuitry to reject false
data, such as standing in
12 line. Typically, the logic sets outer time limits on acceptable data, such
as one half second to
~ 3 five seconds for snowboarding, one quarter second to three seconds for
roller-blading, and user
4 selected limits, targeted to a particular user's interest or activity. The
logic circuitry of the
airtime sensing unit preferably also works with a speed sensor, as discussed
herein; and the
6 logic operates to measure airtime only when the sensing unit is moving above
a minimum
7 speed. For example, when the sensing unit includes an airtime sensor and a
speed sensor, the
18 logic ensures that airtime data is measured only if there is motion. Such
logic then ensures that
9 false data corresponding to standing in line is not recorded as performance
data. The speed
limits tied to the logic are preferably selectable by the user; though certain
default speeds are
21 set for certain activities. For example, for skiing and snowboarding, 5mph
is a reasonable
22 lower speed limit, such that all airtime, drop distance and/or power
measurements are ignored
23 at lower speeds. For roller-blading, the lower limit of speed is reasonably
lmph, as for wind-
24 surfing.
(8) Toggle to other device functionality. Although this section describes an
airtime sensing
26 unit, many sensing units of the invention incorporate at least two sensors,
such as: airtime
27 sensor and speed sensor: airtime sensor and power sensor; airtime sensor
and drop distance
28 sensor; a combination of airtime, power, and drop distance sensors; a
combination of airtime,
29 drop distance and speed sensors; a combination of airtime, power and speed
sensors; and a full
1 3o sensing unit of airtime, speed, power and drop distance sensors.
Accordingly, a toggle button is
3 t usually included with the sensing unit (or alternatively with the data
unit) such that the user can
32 toggle to data corresponding to the desired performance data. Similar
toggle buttons can be
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1 included with the sensing unit or data unit (which transmits data to the
sensing unit) to activate
2 only certain portions of the sensing unit, e.g., to turn off speed sensing.
Alternatively, data
3 from any given sensor can be acquired according to user-specified
requirements.
4 Those skilled in the art should appreciate that a sensing unit with multiple
sensors can
5 simply acquire all the data, and that the data is sorted according to user
needs and requests by
6 toggle functionality at the data unit or at the base station (i.e., such as
entering a request for the
7 desired information at the computer keyboard).
8 (9) User interface to control parameters. As discussed above, the sensing
unit and/or data
9 unit preferably include buttons or toggle switches for the user to interact
with the unit. For
to example, one of the units should include an ON/OFF switch, and at least one
button to
11 command the display of performance data.
12 In other aspects, the airtime data of 1-6 can be shown on a display
connected with the
13 sensing unit, or they can be transmitted to an associated data unit, or to
a base station.
14
Speed Sensing Unit
16 One sensing unit of the invention measures "speed." This speed sensing unit
is
17 preferably battery-powered and includes a microprocessor (or
microcontoller). The speed
1 s sensing unit either connects to a data unit; or can include a low-powered
liquid crystal display
19 (LCD) to communicate the "speed" to the user. Certain sporting activities
also benefit by the
2o measurement of speed, including skiing, snowboarding, mountain biking, wind-
surfing, roller-
21 blading, and others. To detect user motion, the sensing unit includes a
speed sensor such as a
22 Doppler module, as described in U.S. Patent Nos. 5,636,146, 4,722,222, and
4,757,714,
23 incorporated herein by reference. Alternatively, the speed sensor can
include a microphone
24 subsystem that detects and bins (as a function of frequency} certain sound
spectra; and this data
is correlated to known speed frequency data. A speed sensor can also include a
microphone
26 which, when coupled with the controller subsystem, detects a "pitch" of the
vehicle; and that
27 pitch is used to determine speed to a defined accuracy (typically at least
Smph). The speed
2s sensor can alternatively include a Faraday effect sensor (which interacts a
magnetic field with
29 an electric field to create a voltage proportional to speed). Specifically,
the Faraday effect
3o sensor sets up a current that runs orthogonal to the speed direction. In
one aspect, the current is
31 created between two electrodes formed by the two metal edges of a ski or
snowboard (in circuit
32 with the snow). When the Faraday effect sensor moves, a voltage is created
proportional to
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velocity. The magnetic field is formed by a magnet that creates a flux
substantially
2 perpendicular to the current flow (those skilled in the art should
appreciate that the
3 orthogonality of the respective quantities can be compensated by a sine
function if the
4 quantities are not orthogonal, to retrieve the speed data).
. 5 In another aspect, a sensing unit with a microphone, for example, can
benefit with the
6 user of an electrical filter with a variable bandpass that tracks the
dominant spectral content,
7 denoted herein as a "tracking filter."
s This speed sensing unit can be stand-alone, or a speed sensor can be
integrated into a
9 sensing unit with multiple sensors, such as described above. For example,
one speed sensing
1 o unit provides both "air" time and speed to the user of the device.
11 Preferably, the electronics for the speed sensing unit are conveniently
packaged within
12 a single integrated circuit such as an ASIC. A digital memory stores speed
data; or
13 alternatively, the speed sensing unit transmits speed performance data to a
data unit or to the
14 base station.
15 The speed sensing unit preferably provides several facets of speed
performance data,
16 such as any of the following information data and features:
1'7 ( 1 ) Average and peak speed for the day. In this aspect, the speed
sensing unit provides at
18 least the peak speed for the day. The sensing unit can also integrate all
speeds for the day to
1 ~ provide an average speed.
20 (2) Speed for any particular period or run. This aspect of the speed
sensing unit provides
21 substantially real-time data to the user such as the speed reached in a
recent run. By way of
22 example, a data unit with headphones can provide this data immediately
(e.g., continually
23 informing the user of data such as "25mph" or "l ymph"). Alternatively, the
speed data for the
24 run or period is stored within memory (either within the data unit or in
the sensing unit) so that
25 the user can retrieve the data at his convenience. For example, data for a
particular run or
26 period can be retrieved from a watch data unit on the chairlift after a
particular run. In this
27 manner, the user can have substantially real-time feedback for recent
periods.
28 (3) Successive records of speed. In this aspect, peak or average speed
records over a
29 selected period (e.g., one day) are stored in memory either in the data
unit or in the speed
3o sensing unit. These speed "records" are retrieved from the memory at the
user's convenience.
31 The system can also simply store such records until the memory is full, at
which time the
32 oldest record is over-written to provide room for newer speed data. The
data can also be
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1 transmitted to a base station which includes its own memory storage for
retrieval by the user.
2 (4) Averages and totals, selectable by the user. In this aspect, the sensing
unit or data unit
3 (or the base station) saves speed data within memory for later retrieval by
the user. The period
4 for which the data is valid is preferably selectable by the user. The data
of this aspect
preferably includes speed averages over that period.
6 (S) Rankings of records. In this aspect, the sensing unit or data unit (or
base station) saves
7 speed data within memory for later retrieval by the user. For example, the
user obtains speed
8 data through the data unit while on the chairlift or later obtains the data
in print-out form at the
9 base station, or a combination of the two. The period for which the data is
valid is preferably
to selectable by the user. One record can include peak and/or average speed,
over that period. The
11 records are preferably ranked by velocity, the fastest to the slowest
speeds.
12 (6) Logic to reject data representing contaminated speed data. The
preferred speed sensing
13 unit includes logic circuitry to reject false data, such as data
corresponding to two hundred
14 miles per hour. Typically, therefore, the logic sets outer speed limits on
acceptable data, such
as seventy miles per hour for a skier, as an upper limit, to one or five miles
per hour as a lower
16 limit (data that is slower than this rate is not, generally, of interest to
skiers). Other reasonable
t 7 limits are 70mph to Smph for snowboarding, 40mph to Smph for roller-
blading. User selected
18 limits can also be used within the speed sensing unit and targeted to a
particular user's interest
19 or activity.
(7) Toggle to other device functionality. Although this section describes a
speed sensing
21 unit, many sensing units of the invention incorporate at least two sensors,
such as: speed sensor
22 and power sensor; speed sensor and drop distance sensor; and a combination
of speed, power,
23 and drop distance sensors. Accordingly, a toggle button is usually included
with the speed
24 sensing unit (or alternatively with the data unit) such that the user can
toggle to data
corresponding to the desired performance data. Similar toggle buttons can be
included with the
26 sensing unit or data unit (which transmits data to the sensing unit) to
activate only certain
27 portions of the sensing unit, e.g., to turn off airtime or drop distance
sensing. Alternatively,
28 data from any given sensor can be acquired according to user-specified
requirements.
29 (8) User interface to control parameters. As discussed above, the speed
sensing unit and/or
3o data unit preferably include buttons or toggle switches for the user to
interact with the unit. For
31 example, one of the units should include an ON/OFF switch, and at least one
button to
32 command the display of performance data.
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1 In one aspect, a sensing unit with multiple sensors simply acquires all the
data, and that
2 data is sorted according to user needs and requests by toggle functionality
at the data unit or at
3 the base station (i.e., such as entering a request for the desired
information at the computer
4 keyboard).
6 Power Sensin. Unit
7 One sensing unit of the invention measures "power", a measure of the amount
of
8 energy absorbed or experienced by a user during the a period such as a day.
The power sensing
9 unit thus provides a measure of the intensity or how "hard" the user played
during a particular
to activity. The components for this power distance sensing unit can include
one or more
i l microphones or accelerometers to sense vibration or ' jerk" of the user or
the user's vehicle
12 relative to the ground. For example, one power sensing unit provides a
kayaker with the ability
13 to assess and quantify the power or forces experienced during a white-water
ride. The power
i4 sensing unit is preferably battery-powered and includes a microprocessor
(or microcontoller).
In one aspect, "power" is measured through an accelerometer. In another
aspect, the power
16 sensor includes a microphone, as discussed below. As before, the power
sensing unit is stand-
17 alone, or it can be incorporated with other units discussed herein.
Preferably, the electronics for
18 the power sensing unit are conveniently packaged within a single integrated
circuit such as an
19 ASIC. A digital memory stores power data; or alternatively, the power
sensing unit transmits
2o power performance data to a data unit. One power sensor according to the
invention is an
21 accelerometer, oriented in the direction most indicative of energy expended
(e.g., for skiing,
22 the accelerometer is preferably oriented perpendicular to the ski surface).
Another power
23 sensor is a microphone, preferably mounted within an enclosure which
generates sound in
24 response to user activity.
The power sensing unit preferably provides several facets of power performance
data,
26 such as any of the following information data and features:
27 ( 1 ) Peak and average power for the day. In one aspect, a power sensor is
an accelerometer
28 which generates analog data that is digitally sampled by the controller
subsystem at a rate such
29 as 1000Hz, 100Hz or IOHz. This digitally sampled data is integrated over a
"power period"
3o such as one-half second, one second, five seconds, ten seconds, fifteen
seconds, twenty
31 seconds, thirty seconds, one minute, or five minutes (depending on the
sporting activity) - to
32 specify a power "value". In another aspect, a peak power is determined for
power values over a
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given user-selected period, e.g., one minute, one day, or other user-selected
period, and stored
2 within memory (in the sensing unit, in the data unit, and/or in the base
station) for subsequent
3 retrieval by the user. The power sensing unit can also provide an average
power value over that
4 period. By way of example, for snowboarding, a user might experience very
high power
activity over a period of fifteen seconds, such as within a mogul run. By
determining power
6 values over one second intervals (i.e., the "power period"), the mogul run
power activity will
7 clearly stand out as a power event in the subsequent data analysis. The
power period can be
8 user selected, such as over a run down a slope on a mountain. For example,
snowboarders over
9 a run down a slope can integrate power values over that period to determine
a total value,
1o which can be compared amongst users. Alternatively, the integrated value
can be divided by
11 the total number of samples to determine an average power over that run.
12 (2) Successive power records. In this aspect, peak power records are stored
in memory
13 either in the data unit or in the power sensing unit. These power "records"
are retrieved from
t4 the memory at the user's convenience. The system can also store such
records until the
memory is full, at which time the oldest record is over-written to provide
room for newer
16 power data. The data can also be transmitted to a base station which
includes its own memory
n7 storage for retrieval by the user.
18 (3) Rankings of records. In this aspect, the power sensing unit or data
unit (or base station)
19 saves power data within memory for later retrieval by the user. For
example, the user obtains
2o power data through the data unit while on the chair-Iift or later obtains
the data in print-out
21 form at the base station, or a combination of the two. The period for which
the data is valid is
22 preferably selectable by the user. The data of this aspect includes power
records, over that
23 period, and the power records are preferably ranked by the Largest to the
smallest.
24 {4) Logic to ignore data that contaminates power data. By way of example,
data from
sensors such as accelerometers can provide noise spikes that correspond to
unreasonable power
26 values; and the logic operates to delete such noise spikes.
2'7 (5) Toggle to other device functionality. Although this section describes
a power sensing
28 unit, many sensing units of the invention incorporate at least two sensors,
such as a power
29 sensor and drop distance sensor. Accordingly, a toggle button is usually
included with the
sensing unit (or alternatively with the data unit) such that the user can
toggle to data
31 corresponding to the desired performance data. Similar toggle buttons can
be included with the
32 sensing unit or data unit (which transmits data to the sensing unit) to
activate only certain
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1 portions of the sensing unit, e.g., to turn off drop distance sensing.
Alternatively, data from any
2 given sensor can be acquired according to user-specified requirements.
3 (6) User interface to control parameters. As discussed above, the sensing
unit and/or data
4 unit preferably include buttons or toggle switches for the user to interact
with the unit. For
5 example, a sensing unit of one aspect includes an ON/OFF switch and at least
one button to
command the display of performance data. Since power can be scaled to
correspond to real
7 data such as "g's" or "joules", one button can be used to change the units
of the power values.
8
9 Drop Distance Sensing Unit
I o One sensing unit of the invention measures "drop distance". This drop
distance sensing
11 unit is preferably battery-powered and includes a microprocessor (or
microcontoller). The drop
12 distance sensing unit either connects to a data unit; or can include a low-
powered liquid crystal
~ 3 display (LCD) to communicate the "drop distance" to the user. The
components for a drop
14 distance sensing unit of one aspect includes a pressure sensor or
altimeter. Preferably, the
15 electronics for the drop distance sensing unit are conveniently packaged
within a single
16 integrated circuit such as an ASIC. A digital memory unit stores drop
distance data; or
alternatively, the drop distance sensing unit transmits drop distance
performance data to a data
1 s unit.
19 The drop distance sensing unit preferably provides several facets of drop
distance
performance data, such as any of the following information data and features:
21 (I) Total and peak drop distance for the day. In this aspect, the drop
distance sensing unit
22 provides at least the peak drop distance for the day. The sensing unit can
also integrate all drop
23 distances for the day to provide a total drop distance.
24 (2) Drop distance for any particular jump. This aspect of the drop distance
sensing unit
provides substantially real-time data to the user such as the drop distance
for a recent jump. By
26 way of example, in one aspect, a data unit with headphones provides this
data immediately
27 after the jump. Alternatively, the drop distance data for the jump is
stored within memory
2s (either within the data unit or in the sensing unit) so that the user can
retrieve the data at his
29 convenience. For example, data for a particular jump can be retrieved from
a watch data unit
' 30 on the chairlift after a particular run which included at least one jump.
In this manner, the user
31 can have substantially real-time feedback for the drop distance event.
32 (3) Successive jump records of drop distance. In this aspect, jump records
over a selected
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1 period (e.g., one day) or stored in memory either in the data unit or in the
drop distance sensing
2 unit (or at the base station). These drop distance "records" are retrieved
from the memory at the
3 user's convenience. The system can also store such records until the memory
is full, at which
4 time the oldest record is over-written to provide room for newer drop
distance data. The data
s can also be transmitted to a base station which includes its own memory
storage for retrieval by
6 the user.
'7 (4) Averages and totals, selectable by the user. In this aspect, the
sensing unit or data unit
g (or the base station) saves drop distance data within memory for later
retrieval by the user. The
9 period for which the data is valid is preferably selectable by the user. The
data of this aspect
I o includes drop distance averages, over that period, or drop distance time
totals, corresponding to
11 the summation of those drop distances over that period.
t2 (5) Rankings of records. In this aspect, the sensing unit or data unit (or
base station) saves
13 drop distance data within memory for later retrieval by the user. For
example, the user obtains
14 drop distance data through the data unit while on the chair-lift or later
obtains the data in print-
15 out form at the base station, or a combination of the two. The period for
which the data is valid
16 is preferably selectable by the user. The data of this aspect includes drop
distance records, over
17 that period, and the drop distance records are preferably ranked by size,
the largest distance to
18 the smallest.
19 (6) Logic to reject activities which represents false drop distance. The
preferred drop
2o distance sensing unit includes logic circuitry to reject false data.
Typically, the logic sets outer
21 drop distance limits on acceptable data, such as three feet to one hundred
feet for snowboarding
22 and skiing (or up to 150 feet for extreme sports), and user selected
limits, targeted to a
23 particular user's interest. The logic circuitry of the drop distance
sensing unit preferably also
24 works with an airtime sensor, as discussed above; and the logic operates to
measure drop
25 distance only when there is a detected airtime. For example, when the
sensing unit includes an
26 airtime sensor and a drop distance sensor, the logic ensures that drop
distance data is measured
27 only if there is an airtime event, which can include its own logic as
discussed above. The limits
2$ for other sports varies. In roller-blading, for example, the drop distance
limits can be set to one
29 foot minimum to ten or fifteen feet maximum.
30 (7) Toggle to other device functionality. Although this section describes a
drop distance
31 sensing unit, many sensing units of the invention incorporate at least two
sensors, such as: drop
32 distance sensor and speed sensor; drop distance sensor and power sensor;
drop distance sensor
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17
1 and airtime sensor; and combinations. Accordingly, a toggle button is
usually included with the
2 sensing unit (or alternatively with the data unit} such that the user can
toggle to data
3 corresponding to the desired performance data. Similar toggle buttons can be
included with the
4 sensing unit or data unit (which transmits data to the sensing unit) to
activate only certain
. 5 portions of the sensing unit, e.g., to turn off speed sensing.
Alternatively, data from any given
6 sensor can be acquired according to user-specified requirements.
7 (8) User interface to control parameters. As discussed above, the sensing
unit and/or data
8 unit preferably include buttons or toggle switches for the user to interact
with the unit. For
9 example, the sensing unit of one aspect includes an ON/OFF switch, and at
least one button to
1 o command the display of performance data such as drop distance.
11 In one aspect, the invention incorporates a pair of power meters that
measure and
12 quantify a competitors performance during mogul competitions. In this
application, one device
13 is mounted to the ski (or lower body, such as the lower leg}, and another
to the upper body. An
14 RF signal unit communicates readings from both devices to a signal
controller at the judges
15 table. The combined signals determine the force differential between the
lower legs and the
16 upper body, giving an actual assessment of a competitor's performance. The
device starts
17 transmitting data at the starting gate. The device of this aspect can also
be coupled to the user
18 via a data unit with headphones to provide a hum or pitch which tells the
user how effective
19 his/her approach is.
2o In another aspect, the invention provides a performance system which gauges
the
21 negative airtime aspects of speed skiers. For example, it is undesirable
for skiers such as
22 Tommy Moe to lift off of the ground during training, and certainly during a
speed event, which
23 slows the skier's speed. In this aspect, the system informs the user (in
real time, via a data unit)
24 of instances of air time so that the skier can adjust and improve his
competitive position.
25 Airtime in this aspect is thus typically less than three seconds and can be
as small as one tenth
26 of a second or less. The data is preferably also communicated to a base
station so that the data
27 can be replayed together with a video of the run, so that the skier can get
real time feedback of
28 airtime (unwanted in speed skiing) while watching his technique.
29 In another aspect, the invention provides a speed and airtime sensing unit
such as
3o described above, and additionally provides a height sensor integrated with
the sensing unit. In
31 one aspect - identified herein as the "default" height measure - the height
sensor detects speed
32 and converts that speed data to height. Many jumps performed in sporting
events such as
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1 snowboarding occur off of a ledge, such that "height" is determined solely
by the force of
2 gravity. In one aspect, therefore, drop distance height is determined by %2
atz , where a is the
3 acceleration due to gravity (9.81meters per second squared, at sea level)
and where t is airtime,
4 as determined by an airtime sensor as described herein. By way of example,
for a one second
airtime, a drop distance of 4.9 meters is measured. This result is
approximately true even if the
6 airtime occurs on a slope down a mountain. However, this calculation will be
in error if there is
an upward or downward motion at the start of the airtime. For example, if a
jump occurs off of
8 a mogul and the user is launching upwards into the air, then this
calculation will produce an
9 incorrect number. Accordingly, the height sensor preferably includes a level
sensor which
o senses and measures the angle of motion relative to a plane perpendicular to
the force of
11 gravity. This angle determines the distance which should be added or
subtracted from the
12 default measure. By way of example, if at the beginning of a two second
airtime, the user
13 moves at a speed of I Omph (about 4.47 m/s), at an angle of 1 S degrees
upwards (such as off a
14 mogul), then the velocity vector in the vertical direction, V~, is
sin(IS°)*lOmph; and the
is distance added to the default measure is approximately
sin(15°)*2(V~2)/a, or I.OSm. The time
16 for this upward-traveled distance is sin(15°)*2V~/a, or 0.24s. The
default time in this example
17 is thus total airtime - 0.24s; and the default measure is 15.2m. The total
drop distance is then
18 15.2m plus 1.OSm, or 16.25m.
19 In one aspect, the invention provides a system for determining the loft
time of a moving
2o vehicle off of a surface. A loft sensor senses a first condition that is
indicative of the vehicle
2 t leaving the surface, and further senses a second condition indicative of
the vehicle returning to
22 the surface. A controller subsystem, e.g., typically including a
microprocessor or
23 microcontroller, determines a loft time that is based upon the first and
second conditions, and
24 the loft time is preferably displayed to a user of the system by a display,
e.g., a LCD or LED
25 display. In another aspect, a power module such as a battery is included in
the system to power
26 the several components. In addition, a housing preferably connects and
protects the controller
27 subsystem and the user interface; and further includes an interface
(possibly including velcro)
28 that facilitates attaching the housing to the vehicle.
29 One preferred aspect of the invention includes a speed sensor, connected to
the controller
3o subsystem, which senses a third condition that is indicative of a velocity
of the vehicle (or at least
31 indicates that the vehicle is in forward motion). In this aspect, the
controller subsystem includes
32 means for converting the third condition to information representative of a
speed of the vehicle.
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I Alternatively, the speed sensor is used as logic for the airtime sensor to
switch off the collection
2 of data when there is no forward motion. According to one aspect, the system
provides a user
3 with airtime and speed of the vehicle.
In yet another aspect, a display of the invention displays selective
information, including
one or more of the following: the loft time; a speed of the vehicle; a peak
loft time; an average
6 loft time; a total loft time; a dead time; a real activity time; an average
speed; successive records
7 of loft information; successive records of speed information; a distance
traveled by the vehicle;
8 and a height achieved by the vehicle off of the surface.
9 In still another aspect, the invention includes a user interface for
providing external inputs
o to the sensing and/or data units, including one or more of the following: a
startlstop button for
11 selectively starting and stopping the acquisition of data; a display-
operate button for activating
12 the display selectively; a speed/loft/power/drop distance toggle button for
alternatively
l3 commanding a display of different performance data; means for commanding a
display of
14 successive records of performance data selectively; means for commanding a
display of
information corresponding to average performance data; means for commanding a
display of
16 dead time; means for commanding a display of distance traveled by the
vehicle upon which the
17 user rides; means for commanding a display of height achieved by the
vehicle off of the surface;
I8 and means for commanding a display of real activity time.
19 Preferably, the controller subsystem of the invention includes a clock
element, e.g., a 24-
2o hour clock, for providing information convertible to an elapsed time.
Accordingly, the subsystem
21 can perform various calculations, e.g., dead time, on the data acquired for
display to a user. The
22 clock can also be incorporated into a data unit, as a matter of design
choice.
23 In another aspect, the airtime sensor is constructed with one of the
following technologies:
24 (i) an accelerometer that senses a vibrational spectrum; (ii) a microphone
that senses a noise
spectrum; (iii) a switch that is responsive to a weight of a user of the
vehicle; (iv) a voltage-
26 resistance sensor that generates a voltage indicative of a speed of the
vehicle; and (v) a plurality
27 of accelerometers connected for evaluating a speed of the vehicle.
2s In another aspect, induced-strain sensors, such as a piezoceramics (e.g.,
PZT, or lead
29 zirconate), piezopolymer (e.g., PVDF), or shape memory (e.g., NiTiNOL)
elements can be
~ 3o used in sensors discussed herein. An "induced strain" sensor provides a
measurable output such
31 as a voltage in response to an applied strain, generally a compressive
strain. Also, strain gages
32 and load cells (which are usually made using strain gage bridges) can also
be incorporated into
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1 sensors herein: the former for measuring bending strains, the latter for
forces and compressive
2 strains. In still another aspect, FSRs (force sensing resistors), such as
those manufactured by
3 IEE Interlink, can be used. The FSRs are pads consisting of inter-digitated
electrodes over a
4 semi-conductive polymer ink, wherein the resistance between the electrodes
decreases
5 nonlinearly as a function of applied compressive load, with high sensitivity
and low cost.
6 In a preferred aspect, the airtime sensor of the invention senses a spectrum
of information,
7 e.g., a vibrational or sound spectrum, and the controller subsystem
determines the first and
8 second conditions relative to a change in the spectrum of information.
Further, the controller
9 subsystem interprets the change in the spectrum to determine the loft time.
For example, one aspect of an airtime sensor according to the invention
includes one or
11 more accelerometers that generate a vibrational spectrum of the vehicle. In
such an aspect, the
12 first and second conditions correspond to a change in the vibrational
spectrum. By way of
13 another example, one airtime sensor of the invention includes a microphone
subassembly that
~4 generates voltages corresponding to a noise spectrum of the vehicle; and,
in this aspect, the first
~ 5 and second conditions correspond to a change in the detected noise
spectrum. Because these
16 spectrums are influenced by the particular activity of a user, e.g.,
standing in a ski line, a
17 controller subsystem of the invention preferably includes logic for
assessing boundary conditions
of the spectrum and for excluding certain conditions from the determination of
airtime.
19 Accordingly, if a skier is in a lift line, such conditions are effectively
ignored. One boundary
2o condition, therefore, according to an aspect of the invention, includes an
elapsed time between the
21 first condition and the second condition that is less than approximately
SOOms; such that events
22 that are within this boundary condition are excluded from the determination
of airtime. One other
23 boundary condition, in another aspect, includes an elapsed time between the
first condition and
24 the second condition that is greater than approximately five seconds; such
that events that are
outside this boundary condition are excluded from the determination of
airtime. Because these
26 boundary conditions are important in the aspects of the invention which
utilize a spectrum of
27 information, the sensing and/or data units preferably utilize a user
interface to provide selective
28 external inputs to the controller subsystem and for adjusting the boundary
conditions selectively.
29 In one aspect, the change in a vibration or sound spectrum is detected
through waveform
"enveloping" of the time domain signal, and then by passing the output of this
envelop to a
3 ~ threshold-measuring circuit. Pre-filtering of the signal, especially to
remove low-frequency
32 content beyond high pass filtering.
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2I
1 In still another aspect, the controller subsystem determines a pitch of the
spectrum by
2 isolating a best-fit sine wave to a primary frequency of at least part of
the spectrum and by
3 correlating the pitch to a vehicle speed. Accordingly, the invention of this
aspect detects spectrum
4 information and correlates that information to a speed of the vehicle.
Typically, a higher pitch
frequency corresponds to a higher vehicle speed and a lower pitch frequency
corresponds to a
6 lower vehicle speed. However, in another aspect, the selected pitch
frequency is calibrated
relative to a selected vehicle and speed.
8 In still another aspect, speed is inferred by the amount of energy at
different vibrational
frequencies, as discussed herein.
The invention also provides, in another aspect, means for storing information
including
l t look-up tables with pitch-to-speed conversions for a plurality of
vehicles. This is useful because
12 different vehicles have different associated noise and/or sound spectrums
associated with the
13 vehicle. Accordingly, the invention in this aspect includes memory for
storing the respective
calibration information of the different vehicles (typically in a look-up
table format) so that a user
can utilize the invention on different vehicles and still accurately determine
speed. Specifically, a
16 particular pitch is associated with a particular speed for a particular
vehicle; and that association
n7 is selectively made by the user.
t s In several aspects of the invention, the controller subsystem includes one
or more of the
19 following: means for selectively starting and stopping the acquisition of
data by the sensing unit;
2o means for responding to an external request to activate a display for the
display of performance
21 data; means for responding to an external request to alternatively display
airtime, drop distance,
22 speed and/or power; means for responding to an external request to display
successive records of
23 performance data.
24 The invention also provides certain methodologies. For example, in one
aspect, the
invention provides a method for determining the loft time of a moving vehicle
off of a surface,
26 comprising the steps of: ( 1 ) sensing the vehicle leaving the surface at a
first time; (2) sensing the
27 vehicle returning to the surface at a second time; and (3) determining a
loft time from the first and
28 second times. Preferably, the loft time is provided to the user who
performed the jump via one of
29 the following methods: through a display located with the user, either in a
data unit or within a
3o sensing unit; through a real time feedback heads-up display or headphones;
through a report
3 ~ available at a base station located at the area where the jump occurred,
such as after a day of
32 skiing; and/or through a computer linked to a network like the Internet,
where the airtime data is
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22
1 stored on a server on the network, such as a server located at the area
where the jump occurred.
2 In still anther aspect, the invention provides a~'method of measuring the
amount of
3 "power" a user absorbs during the day. A motion sensor, e.g., a microphone
or accelerometer,
attaches to the vehicle, preferably pointing perpendicular to the top of the
vehicle (e.g.,
perpendicular to the top surface of the snowboard) so that a measure of
acceleration, "force", jerk
6 or jar associated with the user is made. The data from the motion sensor is
integrated over a
7 selected time - e.g., over the time of the skiing day, or over power periods
such as one minute
8 intervals - so that an integrated measure of motion is acquired. By way of
example, if the motion
9 sensor is an accelerometer positioned with a sensitive axis arranged
perpendicular to the top
1 o snowboard surface, then, through integration over the power period, an
integrated measure of
> > "power" is obtained.
~ 2 Those skilled in the art should appreciate that power can be converted to
actual power or
13 similar units - e.g., watts or joules or ergs or Newtons - though real
units are not as important as
14 having a constant, calibrated measure of "power" for each user. That is,
suppose two
snowboarders have power sensors on their respective snowboards. If one person
skis a green
16 slope and another skis a double-diamond, then the integrated value out of
the double-diamond
17 snowboarder will be greater. The units are therefore set to a reasonably
useful value, e.g., generic
18 power "UNITS". In one aspect, the power units are set such that a value of
"100" indicates a
19 typical snowboarder who skies eight hours per day and on maximum difficult
terrain. At the same
2o time, a snowboarder who rides nothing but green beginner slopes, all day,
achieves something far
21 less, e.g., a value of "1 ". In this manner, average skiers on blue,
intermediate slops will achieve
22 intermediate values, e.g., "20" to "50". Other scales and units are of
course within the scope of
23 the invention, and should be set to the particular activity.
24 Units for airtime are preferably set to seconds, such as "1.2s". Units for
speed are
preferably set to miles per hour, killometers per hour, meters per second,
feet per second, inches
26 per second, or centimeters per second. Units for drop distance are
preferably set to feet, meters,
27 inches, or centimeters.
28 In one aspect, the sensing unit (and/or the data unit) has a user
interface. The interface
29 can include a display and/or audible feedback such as through headphones In
one aspect, the
3o audible feedback informs the user of big "air" words such as "awesome" if
for example a
31 snowboarder hit really big air (e.g., over five seconds). In another
aspect, the interface
32 electronics include a low-power piezo "buzzer" or headphone "bud" speaker
that sounds
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23
1 whenever an "air" condition is sensed. This provides immediate feedback to
the user. Further,
2 in another aspect a varying pitch is used to give a speed indication. For
instance, the ear can
3 readily distinguish an octave pitch change, which can for example correspond
to each 5 mph
4 change in speed.
The measure of power according to the invention thus provides significant
usefulness in
6 comparing how strenuous one user's activity is as compared to another. For
example, suppose
7 two users ski only blue, intermediate slopes with the exact same skill and
aggressiveness except
s that one user chooses to sit in the bar for three hours having a couple of
cocktails. At the end of
9 an eight hour day - providing the power period is set for the whole day -
the skier who skied all
to eight hours will have a power measurement that is 8/5 that of his cocktail-
drinking companion.
I I They can thereafter quantitatively talk about how easy or how difficult
their ski day was. As for
12 another example, suppose a third friend skis only double-diamond slopes and
he takes four hours
13 out to drink beer. At the end of the day, his power measure may still be
greater than his friends
14 depending upon how hard he skied during his active time. He could therefore
boast - with
quantitative power data to back him up - that he had more exercise than either
of his friends even
16 though he was drinking half the day.
17 In one aspect, the invention incorporates a breathalyzer - used to measure
a user's
18 consumption (i.e., a blood alcohol level) - and the level is stored such as
within the memory
19 within the controller subsystem. A base station can upload the data to the
memory, as desired.
2o The measure of air time, according to the invention, can also be used in a
negative sense.
21 That is, speed skiers try to maintain contact with the ground as air time
decreases their speed. By
22 monitoring their air time with the invention, they are better able to
assess their maneuvers
23 through certain terrain so as to better maintain ground contact, thereby
increasing their time.
24 The measurement of air, speed and power, and drop distance, in accord with
the
invention, are preferably made through one or more sensors located with the
vehicle, e.g., on the
26 snowboard or ski, upon which the person rides. As such, it is difficult to
see the sensor; so one
27 aspect the invention provides an RF transmitter in the sensing unit. A data
unit coupled to the RF
28 transmitter - e.g., in the form of a watch, paging unit, or radio receiver
with headphones, is
29 located at a convenient location with the person. The performance data -
e.g., air, power, drop
3o distance and speed - is transmitted to the person for convenient viewing,
or listening. In still other
31 aspects, a memory element in the data unit (or alternatively in the sensing
unit) provides for
32 storing selected parameters such as successive records of speed, air, drop
distance and power, or
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24
1 averages for the performance data. Data can also be transmitted from the
sensing unit to a base
2 station, as discussed above. Those skilled in the art should appreciate that
other data transfer
3 techniques can be used instead of RF, including IR data transfer between the
units.
4 In one aspect, the sensing unit internally resets (i.e., shuts off) when the
unit senses no
reasonable or useful performance data for a preselected period of time. By way
of example,
6 through a clock within the microprocessor, the unit automatic time-outs
after that period, saving
7 battery power.
In one aspect, a temperature sensor is included with the sensing unit (or data
unit). A
9 temperature profile is taken over the course of a activity day and is Iater
displayed so that the
user may boast that he or she skied in the most arduous situations.
l l Preferably, performance data is accumulated and then transmitted to a base
station such
12 as a ski lodge. For mountain biking, data can be telemetered back to a club
house. Through the
13 use of Internet connectivity, these data sets can also be downloaded off a
Web site so that the
~4 user can compare different slopes or areas, together with performance. The
data can also be
evaluated and figures of merit can be applied to each run so that a skier can
look at his or her
16 performance and see how they did relative to other users. A skier may find
for example that he
skied better on that trail than any one else all month, year or ever. A
handicap can also be
I8 applied to other mountains and trails so that a national or world
competition is achieved. This
19 interconnectivity is permitted by use of the World Wide Web or simply by
using bulletin
boards that are called up and updated, as known in the art. Telenet or FTP
sites can also contact
2 ~ each other or be contacted by a home site that will assimilate the data
and prepare it for
22 display. Security could be ensured so that a user has confidence that only
he or she can access
23 their own data.
24 The invention thus provides, in one aspect, a national or regional game to
be played so
that the many users can compare and store performance data. Ski areas may use
this data, for
26 example, with the participant's knowledge and consent so that it will lure
skiers to their lifts in
27 the hope that they will win an award. Awards for the highest vertical drop,
most air time,
2s greatest speed or most power may also be awarded. The prizes could simply
be free lift tickets.
29 In one aspect, power for the sensing units (or data units) may be saved
during times of
inactivity by powering off most of the electronics with a solid state switch
such as a MOSFET .
31 The processor or some minimum electronics can remain powered so that when
activity is
32 detected, the remaining electronics are powered as needed. Further, to save
power, sensors such
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1 as accelerometers are duty cycled.
2 In another aspect, downward velocity is determined by knowing the rate of
descent
3 such as through a pressure sensor. Pressure sensing and airtime can thus be
used to determine
4 vertical drop, where loft is determined by the absence of a vibratory noise
floor, for example.
5 In another aspect, the GPS is used to determine speed down a slope. With
updates as
6 frequent as one second, there is more than enough bandwidth to acquire
changing GPS data.
7 GPS however can have large errors associated with uncertainty of positioning
calculations.
s This may be remedied by using differential GPS. Differential GPS makes use
of a fixed GPS
9 Receiver with a known position, such as at the base station. When
functioning as a sensor,
1o therefore, the GPS receiver receives updates from the base station to
maintain accurate
> > position. When large errors are received, they are rejected because the
fixed receiver is at a
12 known position, resulting in a data correction that is also applied to the
moving receiver on the
13 slope. In some areas of the United States, the correction codes for
differential GPS are
14 broadcast for general use.
15 In still another aspect, when using a GPS receiver, individual ski maps for
each trail are
6 downloaded into memory so that the skier may see where they are on the
display. Also, 3D
17 topographical information is also preferably downloaded so that features
can be attached to
t8 these maps and to aid in performance data determination. By knowing the
height in 3D space
19 of the receiver, and with the stored height of the slope in memory, the
distance off the ground
2o is determined. Loft time is also thus determined in addition to vertical
drop. Loft detection with
2 ~ a GPS system may thus return the value of drop distance.
22 In another aspect, speed is determined by use of neural network synthesis.
A neural
23 network extracts speed information from a sensor such as a microphone or an
accelerometer.
24 This is accomplished, for example, by recording microphone data on a ski or
snowboard along
25 with a true speed sensor, such as a Doppler microwave sensor. Two data sets
are thus
26 generated: the first data set contains data acquired from the microphone
that will be used in the
2'7 final system; and the second data set corresponds to the true device that
is used as a reliable
28 speed detector. These two data sets are fed into a neural network, and the
output of the neural
29 filter is then compared with known good speed data. The various weights of
the neural network
3o are adjusted until a match is determined. At this point, the neural network
is used to process the
31 first data set to reliably determine speed. In the event that a match is
not found, a more
32 complex but powerful network is developed. The first data set is then fed
into the new net and
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26
I a match is developed by adjusting the weights of the nodes. This process is
repeated constantly
2 until a match is determined. Each failure results in a larger neural network
but increases the
3 probability that the next filter will achieve a match.
4 In areas where the ski run is visible, the speed and trajectory of a skier
may be achieved
by the use of a digital imaging system, in accord with another aspect. The
imaging system can
6 thus include a CCD camera that looks at the slope and watches skiers
traverse down the slope.
7 By knowing the distances along the slope, and the fact that the camera is
stationary, the
8 distance moved is determined frame to frame, corresponding to position in
time that correlates
9 to speed. Skiers can be identified by signs they wear, including a
distinctive pattern which
to allows identification of individual skiers.
I 1 The invention is next described further in connection with preferred
embodiments, and it
12 will be apparent that various additions, subtractions, and modifications
can be made by those
3 3 skilled in the art without departing from the scope of the invention
14
Brief Description of the Drawings
16 A more complete understanding of the invention may be obtained by reference
to the
17 drawings, in which:
I s FIG. 1 shows a schematic layout of a sensing unit, data unit and base
station, each
19 constructed according to the invention, for providing performance data to
participants in sporting
activities;
21 FIGS. 2, 3, 4 and 5 illustrative certain operational uses of the units of
FIG.1;
22 FIG. 6 graphically illustrates actual vibration data taken during a ski
jump with an airtime
23 sensor utilizing an accelerometer, in accord with the invention;
24 FIGs. 6 and 6A represent processed versions of the data of FIG. 6;
FIG. 7 schematically illustrates a controller subsystem constructed according
to the
26 invention and which is suitable for use in the sensing unit of FIG. 1;
27 FIG. 8 illustrates one exemplary pitch-detection process, in accord with
the invention,
28 which is used to determine speed;
29 FIG. 9 schematically illustrates process methodology of converting a
plurality of
3o acceleration values to speed, in accord with the invention;
31 FIG. 10 schematically illustrates process methodology of calculating speed,
direction,
32 andlor vehicle drop distance, in accord with the invention, by utilizing
accelerometer-based
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27
1 sensors;
2 FIG. 11 illustrates methodology for measuring drop distance, speed and/or
airtime, in
3 accord with the invention, by utilizing a Doppler module as a drop distance,
speed, and/or
4 sensor;
FIG. 12 illustrates an improvement to a snowboard, in accord with the
invention;
b FIGs. 13 and 14 show top and side cross-sectional views, respectively, of a
speed
7 sensor of the invention, coupled to a snowboard, for determining speed by
utilizing charge
s cookies; and FIG. 15 shows a schematic diagram for processing the speed
sensor of FIGS. 13
and 14;
1 o FIG. 16 and 17 show top and side views, respectively, of another
embodiment of a
speed sensor, according to the invention, coupled to a snowboard and utilizing
magnetic
12 cookies to determine speed;
~ 3 FIG. 18 and 19 show top and side cross-sectional views, respectively, of
another
14 embodiment of a speed sensor, according to the invention, coupled to a
snowboard and
~ 5 utilizing optical windows to determine speed;
16 FIG. 20 shows a schematic perspective view - not to scale - of a skier
engaged in
competition on a mogul course and of a system, constructed according to the
invention, for
18 monitoring two power values to quantitatively measure mogul skiing
performance;
19 FIG. 21 schematically illustrates one system including a power sensing unit
2o constructed according to the invention for measuring activity energy for
various sportsmen;
21 FIGs. 22-24 illustrate various, exemplary signals obtainable through the
system of
22 FIG.21;
23 FIG. 25 illustrates an alternative airtime, speed and/or drop distance
measuring system,
24 according to the invention, utilizing a GPS receiver;
25 FIG. 26 schematically shows one airtime and/or power sensing unit of the
invention,
26 mounted to a snowboard;
27 FIG. 27 schematically illustrates a performance system utilizing a data
unit in the form
2s of a watch;
29 FIG. 28 illustrates a GPS-based drop distance sensing unit of the
invention;
3o FIG. 29 shows further detail of the unit of FIG. 28;
31 FIGs. 30-35 illustrate data collection hardware used to reliably collect
large quantities
32 of sensor data at a remote and environmentally difficult location, in
accord with the invention;
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28
1 FIG. 36 shows a schematic view of a pressure-based drop distance sensing
unit of the
2 invention;
3 FIG. 37 illustrates further processing detail of the unit of FIG. 36;
4 FIG. 38 illustrates a power watch constructed according to the invention;
FIG. 39 shows another power watch configuration, in accord with the invention;
6 FIG. 40 shows a schematic view of a power/pressure system according to the
7 invention;
8 FIG. 41 illustrates a two-microphone speed sensing system of the invention;
9 FIG. 42 illustrates process methodology for determining drop distance during
airtime,
1 o in accord with the invention;
11 FIGS. 43 and 44 show real accelerometer data from a ski traveling at <2mph
and
12 >l5mpr, respectively, in accord with the invention;
13 FIG. 45 illustrates one system for interpreting spectral data such as
vibration to
decipher airtime, power and speed, in accord with the invention;
FIG. 47 illustrates a GPS-based system of the invention;
16 FIG. 48 illustrates a neural network of the invention;
17 FIG. 49 illustrates methodology for a two sensor speed sensing unit of the
invention;
18 and FIGS. 50-51 show representative spectra from the two sensors;
19 FIG. 52-53 show illustrative correlation functions;
FIG. 54 illustrates a bending wave within a ski which can be used for power
sensing, in
21 accord with the invention;
22 FIGs. 55-59 show alternative systems to the methodology of FIG. 49;
23 FIG. 60 shows a force measuring system of the invention; and FIGs. 61-62
show
24 alternative systems;
FIGs. 63-73 illustrate force sensing techniques and issues, in accord with the
invention;
26 FIG. 74 shows a network game constructed according to the invention; and
FIG. 75
27 describes further features of the game of FIG. 74;
28 FIGS. 76-83 show further embodiments of the invention; and
29 FIG. 84 illustrates a variety of sport implements incorporating a sensing
unit of the
invention.
31
32 Detailed Description of Illustrated Embodiments
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1 FIG. 1 illustrates a sensing unit 10 constructed according to the invention.
A controller
2 subsystem 12 controls the unit 10 and is connected to one or more sensors
14a-14d. Typically, the
3 subsystem 12 receives data from the sensors 14a-d through data line 16a-d;
though certain sensors
4 14 require or permit control signals, so data lines 16a-d are preferably bi-
directional. It is not
- 5 necessary that the unit 10 incorporate all sensors 14a-14d and only one of
the sensors 14a, 14b,
6 14c or 14d is required so as to provide performance data. In one preferred
embodiment, however,
7 the unit 10 includes all four sensors 14a-14d. In another preferred
embodiment, only the airtime
8 sensor 14b is included within the unit 10.
9 The sensors 14a-14d take a variety of forms, as discussed herein. Generally,
the speed
o sensor 14a provides data indicative of speed to the controller subsystem 12
along data line 16a.
1 ~ One exemplary speed sensor 14a utilizes a microwave Doppler module such as
made by C&K
12 Electronics. The airtime sensor 14b provides data indicative of airtime to
the controller subsystem
~ 3 12 along data line 16b. One exemplary airtime sensor 14b utilizes a
microphone such as a piezo
14 foil by AMP Sensors, Inc. The drop distance sensor 14c provides data
indicative of drop distance
15 to the controller subsystem 12 along data line 16c. One exemplary drop
distance sensor 14c
t 6 utilizes a surface mount altimeter such as made by Sensym, Inc. The power
sensor 14d provides
17 data indicative of power to the controller subsystem 12 along data line
16d. One exemplary power
t 8 sensor 14d utilizes an accelerometer such as made by AMP Sensors, Inc. or
Analog Devices, Inc.
9 In certain embodiments, one sensor 14 functions to provide data that is
sufficient for two
20 or more sensors 14. By way of example, in one embodiment, the airtime
sensor 14b incorporates a
21 microphone or piezo-foil which senses noise vibration of the unit 10. This
noise vibration data is
22 used to sense motion (and/or coarse speed) and power; and thus a single
sensor 14b functions to
23 provide data for sensors 14a and 14d. Those skilled in the art should thus
appreciate that the
24 number of sensors 14 is variable depending upon the type of sensing
transducer and upon the
25 processing capability of the subsystem 12 (e.g., a DSP chid within the
subsystem 12 can provide
26 flexible processing of data from the sensors 14 to limit the number of
sensors 14 required to
2'7 provide performance data); and that the number of sensors 14 is made for
illustrative purposes.
28 The controller subsystem 12 preferably includes a microprocessor or
microcontroller 12a
29 to process data from the sensors 14 and to provide overall control of the
unit 10. The
3o microprocessor 12a can include a 24hr. clock to provide certain performance
data features as
3 ~ described herein. The subsystem 12 also preferably includes digital memory
12b to store
32 parameters used to process data from the sensors 14 and to store
performance data for later
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1 retrieval. The subsystem 12 also preferably includes logic 12c to restrict
data from the sensors 14
2 to reasonable data compatible with certain limits such as stored within
memory 12b. For example,
3 the memory 12b can store speed limits for the speed sensor 14a, and the
logic 12c operates such
4 that any data received from data line 16a is ignored if above or below a pre-
set range (typically,
5 one to five seconds for sport activities such as snowboarding).
Those skilled in the art should appreciate that alternate configurations of
memory 12b and
'7 logic 12c are possible. By way of example, these elements 12b and 12c can
be incorporated
s entirely within the microprocessor 12a; and thus the configuration of the
subsystem 12 is
9 illustrative and not limiting. In addition, in certain embodiments of the
invention as described
herein, memory 12b and/or logic 12c are not required, since relatively raw
data is acquired by the
1 ~ unit 10 and transmitted "off board" through an optional remote data
transmit section 22 (e.g., an
12 RF transmitter) and to a data unit 30 or to a base station 50. In such
embodiments, the raw data is
13 processed within the data unit 30 or the base station 50 so that a user of
the unit I O can obtain
performance data from the data unit 50 and/or base station 70.
15 To acquire signals from the sensors 14, the controller subsystem 12
typically includes A/D
16 converters 12d, such as known in the art. Each sensor 14 also typically
includes a preamplifier 20
17 which amplifies the signal from the transducer within the sensor 14 prior
to transmission along the
t 8 associated data line 16. Those skilled in the art should however
appreciate that the exact
configuration of the preamplifier 20, microprocessor 12a and the A/D
converters 12d depend upon
2o specifics of the sensor 14 and the subsystem 12. For example, certain
sensors 14 available in the
21 marketplace - such as an accelerometer subsystem - include pre-
amplification and A/D
22 conversion; so the data line 16 and subsystem 12 associated with such a
sensor should support
23 digital transmission without redundant A/D conversion.
24 In one embodiment, the sensing unit 10 is "stand alone" and thus includes a
user interface
25 24 that connects to the controller subsystem 12 via a data line 26. The
interface 24 includes an
26 ON/OFF switch 24a, to manually turn the unit 10 ON and OFF, and one or more
buttons 24b
2'7 (preferably including at least one toggle button to other unit
functionality) to command various
28 actions of the unit 10, e.g., the display of different performance data on
the display 24c. Those
29 skilled in the art should appreciate that the interface 24 is illustrative,
rather than limiting, and that
3o elements such as the display 24c can reside in other areas of the unit 10.
The data line 26 is
31 preferably bi-directional so that user commands at the interface 24 are
recognized and
32 implemented by the subsystem 12 and so that performance data stored in the
memory 12b is
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31
1 displayed, upon command, at the display 24c.
2 A battery 30 is generally used to power the unit 10, including the user
interface 24,
3 controller subsystem 12 and sensors 14, if power is required. As such, back-
plane power lines 30a
4 are shown to connect the battery 30 to the various elements 24, 12, 14. One
preferred sensor
however is a piezo-foil that does not require power, and thus such a
connection 30a may not be
6 required for a sensor with a foil (note that the preamplifier 20 may still
require power).
7 The unit 10 is generally enclosed by an appropriate housing 32, such as a
plastic injected
8 molded housing known in the art. The housing 32 is rugged to withstand the
elements such as
9 snow, water and dirt. A water-tight access port 32a permits for the removal
and replacement of the
to battery 30 within the housing 32, as required, and as known in the an.
l l When the unit 10 is stand alone, the housing 32 also includes a window 32b
(possibly the
12 surface of the display 24c integrated substantially flush with the housing
surface) in order to see
13 the display 24c. When stand alone, the housing 32 also includes access 32c
to the buttons 24a,
14 24b. The access 32c is for example provided through pliant rubber
coverings; or the buttons 24a,
24b are made as keypads, as known in the art, that integrate directly with the
surface of the
16 housing 32. Other techniques are available; and in each case the buttons
24b, 24a and housing 32
cooperate so as to provide an environmentally secure enclosure for the
electronics such as the
t s microprocessor 12a while providing an operable interface to communicate
with the subsystem 12.
19 The housing 32 preferably includes a universal interface 32d which provides
flexible and
2o conformal mounting to a variety of surfaces, such as to the relatively flat
surface of a snowboard
21 or to a round bar on a mountain bike. The universal interface 32d is
designed to permit stand alone
22 units 10 to be sold in stores regardless of how or where a user mounts the
unit, to determine
23 performance data for his or her particular activity.
24 In certain aspects, the sensing unit 10 is not "stand alone." In
particular, it is sometimes
desirable to mount the sensing unit 10 in an obscure location that is hard to
see and reach, such as
26 on a ski, or with a binding for a ski or snowboarding boot. In such
locations, it is preferable that
27 the unit 10 is a "black box" that is rugged to withstand abuse and
environmental conditions such
2s as water, snow and ice. Therefore, in such a configuration, the user
interface 24 is not included
29 within the unit 10 (since snow and dirt can cover the unit 10), but rather
data from the unit 10 is
3o communicated "off board" such as to the data unit 50. In this
configuration, a data transmit section
31 22 receives data from the subsystem 12 via data bus 23; and transmits the
data to a remote
32 receiver, e.g., the data receive section 56 of the data unit 50 and/or to
the data receive unit 72 of
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32
I the base station 70.
2 The communication between unit 10 and the data unit 50, or base station 70,
is preferably
3 via RF signals 45, known in the art, which utilize antennas 25, 58 and 78.
However, those skilled
4 in the art should appreciate that other data communication techniques are
available, including
infrared transmission, inductively coupled data transmission, and similar
remote (i.e., non-wired)
6 techniques. The data transmit section 22 and antennas 25, 58 and 78 are thus
shown illustratively,
7 whereas those skilled in the art should appreciate that other techniques can
replace such elements,
s as desired, to perform the same function.
9 FIG. 1 thus also shows a schematic view of a data unit 50 constructed
according to the
o invention. As mentioned above, the data unit 50 cooperates with the unit 10
to provide
I I performance data to a user of the unit 10. In one preferred embodiment,
the unit 50 is sized and
12 shaped much like a portable beeper, known in the art, and can include a
display 52 to inform the
13 user of performance data. In another preferred embodiment, the unit 50 is
incorporated within a
14 watch such as provided by manufacturers like TIMEXT"'' or CASIOTM. A
battery 30' provides
power to the elements of the unit 50 through power lines 30a' (in the watch
configuration, the
16 existing battery replaces battery 30'). A user interface 24' operates as
described above (with like
17 numerals) to, for example, provide a display of performance data, upon
command. The unit
Is includes a housing 54 that is also preferably plastic injected molded and
rugged to protect the
19 elements of the unit 50. Although not illustrated, the housing 54
incorporates access ports and
windows, as known in the art, to permit access to the buttons 24b' (preferably
including at least
21 one toggle button to other unit functionality), to view the display 24a'
(as similarly described in
22 connection with the sensing unit 10), and/or to replace the battery 30'.
The antenna 58 represents
23 one technique through which data 45 is communicated between the units 10,
50; although those
24 skilled in the art should appreciate that other communication forms are
within the scope of the
invention, including communication by infrared light.
26 The data unit 50 generally requires a controller such as a microprocessor
53 to control the
27 unit 50 and the elements therein. Data buses 55 provide data interface by
and between the
2s microprocessor 53 and the elements. Accordingly, data entered at the user
interface 24' is
29 bidirectional through data bus 55 so that user commands are received and
implemented by the
microprocessor 53. A memory 50b is typically included within the data unit 50
(or within the
31 processor 53) so as to store parameters and/or performance data, much like
the memory 12b.
32 In a preferred embodiment, performance data is thus made available to a
user via the
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33
I display 52. However, in another embodiment, performance data is transmitted
to a headphones
2 assembly 60 connected, datawise, to the microprocessor 53 so that
performance data is relayed in
3 near real time, as the user performs the associated stunt. The headphones 60
connect to the unit 50
4 by standard wiring 62 and into a jack 64 in the unit 50. For example,
through the user interface
24', the user can command the microprocessor 53 to provide airtime data to the
headphones 60
5 immediately after an airtime is detected. Other performance data can
similarly be set, such as
'7 continual speed playback, through the headphones 60.
8 Performance data can thus be viewed on the display 52 and/or "heard" with
the
9 headphones assembly 60. In either case, a user commands the unit 50 to
provide performance data
to for any memory stored within memory 12b or SOb. Accordingly, data
communication between the
11 units 10 and 50 is preferably bi-directional, so that a user's command at
interface 24' is
12 understood and implemented by the processor 12a.
13 Those skilled in the art should appreciate that the microprocessor 53 need
not be a
14 complex or expensive microprocessor as the majority of the processing for
performance data is
done within the sensing unit 10. As such, the microprocessor 53 can be a
microcontroller which
t6 operates with basic functionality, e.g., to display performance data
corresponding to user inputs at
17 the interface 24'. How processing is apportioned between the units 50, 10
is, however, a matter of
t 8 design choice. That is, for example, most of the processing can be done
within the unit 50,
19 wherein the unit 10 can then have reduced processing capability, if
desired. These choices extend
2o to elements such as the memories 12b, SOb, as they can have redundant
capability. When the unit
2 t 10 is stand alone, a user interface 24 is generally included (unless data
is transmitted directly to the
22 base station 70 for later retrieval). When the system of the invention
includes both units 10, 50,
23 then the user interface 24 is generally not included since the interface
24' sufficiently controls the
24 system. In this latter case, the functionality and configuration of the
microprocessors 12a, 53,
memory 12b,50b and logic 12c are a matter of design choice; and some elements
might be
26 eliminated to save cost. For example, the memory SOb can be designed to
support all memory
2'7 requirements of a system incorporating both units 10, 50 to eliminate
redundancy; and thus
28 memory 12b would not be required.
29 Other configurations of a system combining units 10 and 50 exist. For
example, one
3o configuration eliminates the display 52 so that performance data is only
available via the
31 headphones assembly 60. In another configuration, the sensing unit 10 works
only with the base
32 station 70 and without a data unit 50. Further, such a configuration need
not include a user
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t interface 24 or a display 24c, since all data collected by the unit 10 can
be stored and processed at
2 the base station 70.
3 The base station 70 thus includes an antenna 78 and a data receive unit 72
(or alternatively
4 other wireless communication technology, as known in the art) to collect
data signals 45.
Typically, the base station 70 corresponds to a well known facility located at
the sporting area,
6 such as a ski lodge. A base station computer 74 connects to the base station
data receiver unit 72,
'7 via the bus 76, to collect and process data. As such, one sensing unit 10
of the invention simply
8 includes one or more sensors 14 and enough control logic and processing
capability to transmit
9 data signals 45 to the base station 70, so that substantially all processing
is done at the base station
70. This configuration is particularly useful for aspects of the invention
such as speed skiing,
11 where the sensing unit 10 is mounted with the speed skier's ski, but where
that user has no
12 requirement to view the data until later, after the run {or where
instructors or judges primarily use
t3 the data). However, as discussed above, that speed skier can also use a
data unit 50 with
14 headphones 60 to acquire a real-time feedback of unwanted airtime, such as
through an audible
t 5 sound, so as to correct his or her form while skiing. In one aspect, the
base station 70 preferably
16 has the capability to collect, analyze and store performance data on a
server 80 for later review.
17 Accordingly, the base station 70 includes a computer 74 to collect, analyze
and process
18 data signals to provide performance data to users and individuals at the
base station 70. The
19 performance data is generally stored on a server 82, which can have an
Internet connection 84 so
2o that performance data can be collected from remote locations. If there are
multiple users, which
21 typically is the case, then the sensing unit 10 associated with each user
"tags" the data with a code
22 identifying a particular person or unit 10, such as known in the art. The
server 82 then stores
23 performance data tagged to a particular individual or unit so that the
correct information is
24 provided, upon request (such as through the Internet or through the
computer 74). Performance
25 data can also be printed through printer 86 for users and persons at the
base station 70.
26 Although the base station 70 can be configured to process substantially raw
data signals
27 from units 10 (and particularly from the sensors 14), the base station
typically collects
28 performance data directly from the sensing unit 10 for each of a plurality
of users and stores all the
29 data, tagged to the particular user, in the server 82. The stored data can
then reviewed as required.
3o By way of example, a video station 90 can be included with the base station
70 and users,
3 t instructors or judges can review the performance data in conjunction with
video data collected
32 during the run by known video systems (or television systems).
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1. With further reference to FIG. 1, the displays 24c, 52 can be one of any
assortment of
2 displays known to those skilled in the art. For example, liquid crystal
displays (LCDs) are
3 preferred because of their low power consumption {for example, LCDs utilized
in digital watches,
4 portable computers and paging units are appropriate for use with the
invention). Other suitable
s displays can include an array of light emitting diodes (LEDs) arranged to
display numbers.
6 The headphones assembly 60 can also be replaced with a heads-up display
unit, known in
7 the art, such as described in connection with U.S. Patent No. 5,162,828,
incorporated herein by
s reference.
9 As illustrated in FIG. 2, the invention in one embodiment operates as
follows. The sensing
I o unit 10' is mounted via its housing 32 to a sporting vehicle, such as a
snowboard or mountain
I I bike, or such as the ski 102 of FIG. 2. As illustrated, the skier 100 is
catching air during a jump
12 off the ground 103. The skier 100 can obtain instantaneous airtime data via
headphones 60',
13 discussed above, or he can later retrieve the airtime data through a data
unit 50' (shown
14 illustratively on the skier's jacket 100a when typically the unit 50' would
be within a pocket or
15 connected to a belt of the skier 100) or at a base station 70' (FIG. 1 ).
16 FIG. 3 shows another typical use of the unit 10 of FIG. 1. In particular,
FIG. 3 shows the
I'7 sensing unit 10 mounted onto a ski 126. As is normal, the ski 126 is
mounted to a skier 128 (for
1 s illustrative purposes, the skier 128 is only partially illustrated), via a
ski boot 130 and binding
19 130a, and generally descends down a ski slope 132 with a velocity 134.
Accordingly, one use of a
2o unit 10 with a speed sensor is to calculate the peak speed of the ski i26
(and hence the skier 128)
21 over a selectable period of time, e.g., during the time of descent down the
slope 132. However,
22 the unit 10 also provides information such as drop distance, airtime and
power, as described
23 herein, provided the associated sensors are included with the unit 10.
24 Another use of the unit 10 of FIG. 1 is to calculate the airtime of a
vehicle such as the ski
25 126 (and hence the user 128) during the descent down the slope 132.
Consider, for example, FIG.
26 4, which illustrates the positions of the ski 126' and skier 128' during a
lofting maneuver on the
27 slope 132'. The ski 126' and skier 128' speed down the slope 132' and
launch into the air 136 at
28 position "a," and later land at position "b" in accord with the well-known
Newtonian laws of
29 physics. With an airtime sensor, described above, the unit 10 calculates
and stores the total
3o airtime that the ski 126' (and hence the skier 128') experiences between
the positions "a" and "b"
31 so that the skier 128' can access and assess the "air" time information.
32 FIG. 5 illustrates a sensing unit 10" mounted onto a mountain bike 138.
FIG. 5 also
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1 shows the mountain bike 138 in various positions during movement along a
mountain bike race
2 course 140 (for illustrative purposes, the bike 138 is shown without a
rider). At one location "c"
3 on the race course 140, the bike 138 hits a dirt mound 142 and catapults
into the air 144. The bike
138 thereafter lands at location "d". As above, with speed and airtime
sensors, the unit 10
provides information to a rider of the bike 138 about the speed attained
during the ride around the
6 race course 140; as well as information about the airtime between location
"c" and "d".
7 Airtime sensors such as the sensor 14b of FIG. 1 may be constructed with
known
8 components. Preferably, the sensor 14b incorporates either an accelerometer
or a microphone.
9 Alternatively, the sensor 14b may be constructed as a mechanical switch that
detects the presence
and absence of weight onto the switch. Other airtime sensors 14b will become
apparent in the
t 1 description which follows. For background, consider U.S. Patent No.
5,636,146.
~2 An accelerometer, well known to those skilled in the art, detects
acceleration and provides
~3 a voltage output that is proportional to detected acceleration.
Accordingly, the accelerometer
t4 senses vibration - particularly the vibration of a vehicle such as a ski or
mountain bike - moving
along a surface, e.g., a ski slope or mountain bike trail. This voltage output
provides an
16 acceleration spectrum over time; and information about airtime can be
ascertained by performing
calculations on that spectrum. Specifically, the controller subsystem 12 of
FIG. 1 stores the
18 spectrum into memory 12b and processes the spectrum information to
determine airtime.
19 FIG. 6 shows a graph 170 of an actual vibrational spectrum 172 acquired by
an airtime
2o sensor 14b (utilizing an accelerometer) during a ski jump and stored in
memory 12b, in accord
21 with the invention. The airtime sensing unit was mounted to a ski boot
which in turn was
22 mounted within a ski binding. The sensitive axis of the accelerometer was
oriented substantially
23 vertical to the flat portion of the ski surface. The vertical axis 174 of
the graph 170 represents
24 voltage; while the horizontal axis 176 represents time. At the beginning of
activity 177 - such as
when a user of the sensing unit 10 presses the start/stop button 24a - the
airtime sensor 14b began
26 acquiring data and transferring that data to the controller subsystem 12
via communication lines
27 16b. The initial data appears highly noisy and random, corresponding to the
randomness of the
28 surface underneath the vehicle (i.e., the ski). At time "t," the skier
launched into the air, such as
29 illustrated as location "a" in FIG. 4; and he landed at time "tz," such as
illustrated as location "b"
3o in FIG. 4. The vibrational spectrum 172 between t, and t2 is comparatively
smooth as compared
31 to the spectrum outside this region because the user's vehicle - i.e., the
ski boot - was in the air
32 and was not therefore subjected to the random vibrations of the ski slope
(i.e., vibrations which
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1 travel through the binding, through the boot and into the sensing unit).
Accordingly, the
2 relatively smooth spectrum between t, and t2 is readily discerned from the
rest of the spectrum by
3 the controller subsystem 12 and evaluated for airtime; specifically, airtime
is tz - t~.
FIG. 6 also shows that the spectrum stops at the end I78 of the sporting
activity, when
the controller subsystem stopped taking data (such as in response to an ON/OFF
toggle on switch
6 24a).
7 Typical accelerometer taken from a skier going down a hill is thus shown in
FIG. 6. In
s order to determine power, or shock, in one aspect, the data is accumulated
by taking the
9 absolute value and integrating that data. FIG. 6A graphically shows the
result of integrating
1 o the data of FIG. 6.
1 ~ Another method of the invention for determining a measure of power
associated with
~2 stored accelerometer data is to perform a Fast Fourier Transform on the
data and to integrate
13 the magnitude to find the total energy associated therewith. In the plot of
FIG. 6B, the data
14 from FIG. 6 was transformed with an FFT routine, and then converted to
absolute value, point
by point, and integrated, providing one measure of energy.
16 The data of FIG. 6 can also be reduced to a single number such as via a
root-mean-
7 square of the data. This is done by squaring each sample of the data and
then summing. The
l8 resultant integration can then be divided by the duration of the data
acquisition run, giving a
19 mean, with the resulting number rooted. In the case of the FIG. 6, that
would provide a value
2o 4.0
21 A microphone, also well known to those skilled in the art, detects sound
waves and
22 provides a voltage output that is responsive to detected sound waves.
Accordingly, a microphone,
23 like the accelerometer, mounted to the vehicle senses the vibration of a
vehicle, such as a ski or
24 mountain bike, moving along a surface, e.g., a ski slope or mountain bike
trail. By way of
analogy, consider putting one's ear flat onto a desk and running an object
across the desk. As one
26 can readily determine, the movement of the object on the desk is readily
heard in the ear.
27 Likewise, a microphone within an airtime sensor I4b readily "hears" the
vibrational movements
28 of the vehicle on the surface. Therefore, like the aforementioned
accelerometer, a vibrational
29 spectrum such as shown in FIG. 6 is generated by a microphone-based airtime
sensor during a
' 3o user's sporting activity. As above, the controller subsystem 12 utilizes
this spectrum to determine
31 airtime.
32 A microphone is preferably coupled with a coupling layer of material that
matches the
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impedance for the propagation of compression waves (commonly referred to as
"sound waves"
2 when in air) between the impedance of the vehicle, e.g., the ski or board,
and the microphone
3 transducer, thus transmitting the most "sound" power to the sensor. This
"matching layer" of
4 intermediate impedance is commonly used in sonar, as known in the art, and
it is easily
applied, such as with glue.
6 The airtime sensor 14b of FIG. 1 can also incorporate a switch that rests
below the boot
7 of the ski. Through the switch, the airtime sensor senses pressure caused by
the weight of the user
s within the boot. That is, when the skier is on the ground, the boot squeezes
the switch, thereby
9 closing the switch. The closed switch is detected by the controller
subsystem 12, FIG. 1, as a
discrete input. When a skier jumps into the air, for example, the switch opens
up by virtue of the
1 I fact that relatively no weight is on the switch; and this opened switch is
also detected and input
12 into controller subsystem 12. The controller subsystem 12 counts at known
time intervals (clock
13 rates) for the duration of the opened switch, corresponding to the jump, to
determine airtime.
14 Another airtime sensor 14b of the invention changes capacitance as a
function of a change
of applied pressure. For example, a material beneath the boot that changes
capacitance under
16 varying applied pressures can be used for this airtime sensor. The change
in capacitance is
converted to a digital signal by conditioning electronics within the
controller subsystem 12 to
1 s determine airtime.
The controller subsystem of the invention is constructed with known
components, such as
2o shown in FIG. 7, which illustrates an alternative configuration to the
subsystem 12 of FIG. 1.
21 Specifically, FIG. 7 shows controller subsystem 150 constructed according
to the invention and
22 including a Central Processing Unit (CPU) 152, memory 154, interface
electronics 156, and
23 conditioning electronics 158. The user interface 160, such as the interface
24 of FIG. 1, and
24 including the button inputs 24b, connects to the subsystem 150 such as
shown and directly to the
conditioning electronics 158. The display 162, such as the display 24c of FIG.
l, preferably
26 connects to the subsystem 150 such as shown and directly to the CPU 152.
27 The CPU 152 includes a microprocessor 152a, Read Only Memory (ROM) 152b
(used to
28 store instructions that the processor may fetch in executing its program),
Random Access
29 Memory (RAM) 152c (used by the processor to store temporary information
such as return
3o addresses for subroutines and variables and constant values defined in a
processor program), and
31 a master clock 152d. The microprocessor 152a is controlled by the master
clock 152d that
32 provides a master timing signal used to sequence the microprocessor 152a
through its internal
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1 states in its execution of each processed instruction. The clock 152d is the
master time source
2 through which time may be deduced in measuring velocity or air time (for
example, to determine
3 the elapsed time from one event to another, such as the lapsed time "t," to
"tz" of FIG 6, the clock
4 rate provides a direct measure of time lapse).
The microprocessor subsystem 150, and especially the CPU I52, are preferably
low
6 power devices, such as CMOS; as is the necessary logic used to implement the
processor design.
The subsystem 150 stores information about the user's activity in memory. This
memory
8 may be external to the CPU 152, such as shown as memory 154, but preferably
resides in the
9 RAM 152c. The memory may be nonvolatile such as battery backed RAM or
Electrically
o Erasable Programmable Read Only Memory (EEPROM). Sensor inputs 164 from the
various
t t sensors 14 are connected to the conditioning electronics 158 which
filters, scales, and, in some
~ 2 cases, senses the presence of certain conditions, such as zero crossings.
This conditioning
13 essentially cleans the signal up for processing by the CPU 152 and in some
cases preprocesses the
14 information. These signals are then passed to the interface electronics
156, which converts (by
A/D) the analog voltage or currents to binary ones and zeroes understood by
the CPU 152.
16 The invention also provides for intelligence in the signal processing, such
as achieved by
17 the CPU 152 in evaluating historical data. For example, airtime may be
determined by the noise
18 spectra that changes abruptly, such as indicating a leap, instead of a
noise spectra representing a
19 more gradual change that would occur for example when a skier slows to a
stop. As previously
2o noted, a minimum quiet time is required, in certain embodiments of the
invention, to differentiate
2~ between airtime and the natural motions associated with turning and skiing
(e.g., jump skiing).
22 Further, in other certain embodiments, a maximum time is also programmed to
differentiate
23 airtime from an abrupt stop, such as standing in a lift line.
24 In accord with the invention, if speed is calculated within the sensing
unit 10, FIG. 1,
then the speed sensor 14a can incorporate one or more of the following: (1) a
pitch detection
26 system that detects the "pitch" of the vibrational spectrum and that
converts the pitch to an
27 equivalent speed; (2) a laser-based, RF-based, or sound-based Doppler
module; (3)
28 accelerometers or microphones; (4) pressure transducers; (5) voltage-
resistance transducers; and
29 (6) a DSP subsystem that quantifies and bins accelerometer or sound data
according to frequency.
Other speed sensors 14a will become apparent in the description which follows.
For background,
31 consider U.S. Patent No. 5,636,146.
32 As described above, detection of airtime is facilitated by detecting
motion, which is less
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difficult that determining speed. The above speed sensors are thus also
suitable as "motion"
2 detect sensors that assist the controller subsystem 12 to logic out unwanted
data, e.g., airtime data
3 when standing in line.
4 In accord with one embodiment, a vibrational spectrum is obtained through an
airtime
5 sensor with an accelerometer or microphone embodiment; and this spectrum is
analyzed by the
6 controller subsystem to determine the pitch of the vibration and, thereby,
the equivalent speed. By
'7 way of example, note that a skier generates a scraping sound on hard-packed
snow and ice. When
s the skier changes velocity, that scraping sound changes in pitch (or in
volume). By calibrating the
9 subsystem 12 to associate one pitch (or volume) as one velocity, and so on,
the speed of the
to vehicle (e.g., ski and mountain bike) is determined by spectral content.
One technique for
1 I determining the "pitch" of the spectrum is to determine the best fit sine
wave to the vibrational
12 spectrum data. This sine wave has a frequency, or "pitch" that may be
quantified and used to
13 correlate velocity. The spectrum can also be sampled and "binned" according
to frequency, as
14 discussed below, to determine changes in volume at select frequencies (or
ranges of frequencies}
Is which provide speed correlation.
16 Spectral content may be determined, at least in part, by the conditioning
electronics 158
I'7 of FIG. 7. The electronics can also assess the rise times to infer a
bandwidth of the information.
18 The conditioning electronics I58 and/or CPU 152 can also measure the time
between successive
19 zero crossings, which also determines spectral content.
2o For example, FIG. 8 illustrates a spectrum 166 generated from combination
speed and
21 airtime sensor 14a, 14b in the form of an accelerometer or microphone. The
spectrum 166 thus
22 represents an acceleration spectrum or sound spectrum such as described
herein. The controller
23 subsystem 12 of FIG. 1 evaluates the spectrum 166 and generates a best-fit
sine wave 167 to
24 match the primary frequency of the spectrum 166 over time. FIG. 8 shows
illustratively a
25 situation where a vehicle, such as a ski, moves slowly at first,
corresponding to a lower sine-wave
26 frequency, then faster, corresponding to a higher frequency sine wave, and
then slower again.
27 This pitch transition is interpreted by the controller subsystem as a
change of speed. Specifically,
28 the controller subsystem has calibration data to associate a certain
frequency with a certain speed,
29 for the given vehicle; and speed is thus known for the variety of pitches
observed during an
30 activity, such as illustrated in FIG. 8.
31 Variations in the character of the snow, and other environmental factors
such as sun
32 exposure, and user altitude, can also be factored in speed sensing, in
another asepct. Further,
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1 speed spectra likely varies depending on the characteristic spatial scales)
of the ground, e.g.,
2 the snow for a fixed skier speed. These spatial scales are set by the
temperature at which the
3 snow was deposited, thawing and refreezing cycles, and the sun exposure even
within a day.
4 It should be noted that pitch information (or volume data) is surface
dependent (and
vehicle dependent). For example, a ski-over-snow-speed-spectrum has a
different spectrum than a
6 bicycle-over-ground-spectrum. Accordingly, different calibrations should be
made for different
7 vehicles and speeds, in accord with the invention. Further, certain
spectrums may actually
8 decrease in frequency as speed increases, which should be calibrated to
obtain correct speed
9 information. These calibrations are typically programmed into the controller
subsystem memory,
e.g., the memory 12b of subsystem 12 of FIG. 1. Further, in certain
embodiments of the
11 invention, the sensing unit (or data unit or base station, as appropriate)
stores different spectrum
12 calibrations for different activities so.that a user can move the sensing
unit from one sport to
13 another. Accordingly, one or more buttons such as the buttons 24b are used
to selectively access
14 the different spectrum calibrations.
It is well known that Doppler radar is used by police vehicles to detect
speed; and a speed
16 sensor incorporating a Doppler module can be used to determine speed. U.S.
Patent Nos.
1'7 5,636,146, 4,722,222 and 4,757,714 provide useful background.
1 g FIG. 9 schematically illustrates process methodology, according to the
invention, which
19 converts a plurality of acceleration inputs to speed. For example, when a
plurality of six
accelerometers are connected to a controller subsystem, the process
methodology of the
21 invention is preferably shown in FIG. 9. Specifically, six accelerometers
are connected with
22 various sensitive orientations within a speed sensing unit 14a to collect
pitch 207a, yaw 207b, roll
23 207c, surge 207d, heave 207e, and sway 207f accelerations. These
accelerations are conditioned
24 by the conditioning electronics 158' through the interface electronics 156'
and CPU 152' to
calculate speed, such as known to those skilled in the art of navigational
engineering (for
26 example, Gyroscopic Theory, Design and Instrumentation by Wrigley et al.,
MIT Press (1969);
27 Handbook of Measurement and Control by Herceg et al, Schaevitz Engineering,
Pensauker, NJ,
28 Library of Congress 76-24971 (1976); and Inertial Navigation Systems by
Broxmeyer, McGraw-
29 Hill (1964) describe such calculations and are hereby incorporated herein
by reference). The
3o elements 158', 156' and 152' are similar in construction to the elements
158, 156 and 152
31 described in connection with FIG. 7.
32 FIG. 10 schematically illustrates further process methodologies according
to the
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1 invention wherein the six acceleration inputs 207a-207f are processed by a
controller subsystem
2 of the invention (e.g., subsystem 12 of FIG. 1) such that centripetal,
gravitational, and earth rate
3 compensations are performed so that the various accelerations are properly
integrated and
4 compensated to derive speed (and even direction and distance). Specifically,
a controller
subsystem of the FIG. 10 embodiment includes a centripetal acceleration
compensation section
6 208a which compensates for motions of centripetal accelerations via inputs
of surge 207d, heave
7 207e, and sway 207~ A gravity acceleration compensation section 208b in the
subsystem further
8 processes these inputs 207d-207f to compensate for the acceleration of
gravity, while a earth rate
9 compensation section 208c thereafter compensates for the accelerations
induced by the earth's
1o rotation (e.g., the earth rate acceleration at the equator is approximately
opposite in direction to
~ 1 the force of gravity).
12 Also shown in FIG. 10 are translational integrators 209a-209c which convert
the
13 compensated accelerations from inputs 207d-207f to translational velocities
by integration.
14 Integrators 210a-210c likewise integrate inputs of pitch 207a, yaw 207b,
and roll 207c to angular
velocity while integrators 211a-211c provide a further integration to convert
the angular
velocities to angular position. The angular positional information and
translational velocity
information is combined and processed at the speed and direction resolution
section 212 to derive
speed and direction. Preferably, the subsystem with the components 208, 209,
210, 21 l and 212
is calibrated prior to use; and such calibration includes a calibration to
true North (for a
2o calibration of earth rate).
2 ~ It should be noted that fewer of the inputs 207a-207f may be used in
accord with the
22 invention. For example, certain of the inputs 207a-207f can be removed with
the section 208a so
23 that centripetal acceleration is not compensated for. This results in an
error in the calculated speed
24 and direction; but this error is probably small so the reduced
functionality is worth the space
saved by the removed elements. However, with the increased functionality of
the several inputs
26 207a-207f, it is possible to calculate drop distance in addition to speed
because distance in three
27 axes is known. Therefore, the invention further provides, in one
embodiment, information for
28 displaying drop distance achieved during any given airtime, as described
above.
29 As used herein, "cookie" measurements refer to one technique of the
invention for
3o measuring speed. In this method, for example, the speed sensor drops a
measurable entity - e.g.,
31 electronic charge - into the snow and then picks it up later at a known
distance away to determine
32 the speed. The "charge" in this example is the "cookie."
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I In skiing, for example, this method involves dropping a cookie as the ski
travels and then
2 detecting the cookie at a known distance down the length of the ski. The
time between placement
3 and detection given a known length between the two occurrences determines
the speed. A cookie
4 therefore represents the placement of some measurable characteristic in the
snow underneath.
This characteristic may be electrical charge, magnetic moments, a detectable
material such as ink,
6 perfume, fluorescent dye or a radiation source. The cookies may be dropped
at a constant rate, i.e.
7 cookies per second, or at a fixed distance between cookies. In such cases
the cookies are said to
s be dropped in a closed loop fashion. Also the amount of charge, magnetic
moment, or detectable
9 material may be controlled so that the detection occurs just above
threshold. This tends to
I o minimize the amount of electrical power used and to minimize the amount of
material dispensed.
1 I In one aspect, the cookies correspond to dots of dye that are dropped at
regularly spaced intervals
12 and which glow when irradiated with a pumping light spectrum, for example a
UV pump to drive
13 fluorescence response in blue/blue-green, or a red pump to drive
fluorescence in the IR.
14 In FIGs. 13 and 14, a snowboard 498 traveling in a direction 504 has two
sets of
electrodes attached to the ski. The first electrode set 503 is used to charge
a small amount of snow
16 499 by applying an electric potential across terminals SOIa and SOlb. The
potential in that snow
17 499 is then read by the second set of electrodes 502, accomplished by
sampling the potential
1 s between terminals SOOa and SOOb.
19 Since the level of charge in the snow 499 is quite low, an instrumentation
amplifier may
2o be used to condition the signal, such as known to those skilled in the art.
FIG. 15 shows the
2t charge and detection loop according to one preferred embodiment. A
potential source (e.g., a
22 battery such as battery 30, FIG. 1) with an electrode set 503 are used to
charge the first
23 electrodes SOIa, SOIb. When the output of the instrumentation amplifier 501
is above a
24 predetermined threshold, the control and timing circuit 505 triggers a flip-
flop (not shown) that
notifies the controller subsysetm 12, FIG. 1, that the charge is detected. The
time that transpired
26 between placing the charge at 503 to detecting the charge at 502 is used to
determine speed. The
27 speed is the distance between the two sets of electrodes 503 to 502 divided
by the time between
2s setting and receiving the charge. The functionality of the timing and
control circuit 505 can be
29 separate or, alternatively, can be integrated with the controller subsystem
such as described
3o herein.
31 The second set of electrodes 502 that is used to detect the charge may also
be used to clear
32 the charge such as by driving a reverse voltage (from the control and
timing circuit 505 and
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1 through direct circuitry to the electrodes 502). In this manner to total
charge resulting from the ski
2 traversing the field of snow will be zero so that there will be no charge
pollution. Also it will not
3 confuse another ski speed detection system according to the invention.
4 In summary, the speed sensor of FIGS. 13-15 thus include two electrode
pairs, 503, 502.
The situation described above is also applicable to magnetic moment cookies.
In FIGs. 16
6 and 17, for example, a snowboard 507 shown traveling in a direction 512 has
an electromagnet
7 S I 1 mounted on top of the snowboard 507 and a magnetic sensor 510 at a
rearward position. As
s the snowboarder skis along direction 5 I 2 the electromagnet S 11 impresses
a magnetic moment
9 into the snow and water that resides under the snowboard 507. This is done
by asserting a strong
magnetic field from the electromagnet S 11 and through the snowboard 507 for a
short period of
1 ~ time. This polarization is then detected by the magnetic sensor 510. The
period of time it takes
12 from creating the magnetic moment at 511 to detecting it at 510 is used in
determining the speed
13 of the snowboard 507 (such as through control and timing circuitry
described in connection with
14 FIG. 15). The magnetic sensor 510 may also be used to cancel the magnetic
moment so that the
total magnetic moment will be zero after the ski travels from placement
through detection and
16 removal.
Those skilled in the art should appreciate that the elements 510, 511 are
shown grossly
18 separated, for purposes of illustration. Placing the elements closer (and
preferably within the
19 same housing 32, FIG. 1) increases the required response time of the
controller subsystem,
though it decreases the amount of power required to detect the signal (since
the cookie signal is
2 ~ stronger over a shorter period).
22 A similar speed sensing system is shown in FIGs. 18 and 19. Specifically,
the speed
23 sensor of FIG. 18 includes an optical correlation subsystem with a laser
source and receiver
24 contained in package 522. The laser is directed through two windows 520 and
52I within a
snowboard 530. The laser backscatter is cross correlated over time between the
two windows
26 520, 521. This means that the two time signals are multiplied and
integrated over all time with a
27 fixed time delay between the two signals. The time delay between the two
backscatter signals
28 that yields the highest cross correlation is the period of time the
snowboard takes to travel the
29 distance of the two windows 520, 521. The speed of the snowboard 530 is
determined by
3o knowing the window separation distance. The source does not have to be a
laser but can be
31 noncoherent visible light, infrared or any high frequency electromagnetic
radiation source.
32 One drop distance sensor I4c of the invention utilizes an altimeter such as
manufactured
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1 by Sensym, Inc. The altimeter is calibrated relative to height variations
and the sensing unit 10
2 thereafter monitors pressure change to assess drop distance. Accordingly, in
the preferred
3 embodiment, such a drop distance sensor operates with an airtime sensor 14b
since drop distance
4 is generally only meaningful in connection with a jump. When the sensing
unit 10 detects an
5 airtime, the same period is evaluated through the altimeter to determine
drop distance over that
6 period. Accordingly, altimeter data should be stored in the memory 12b (or
alternatively in the
7 memory 50b, or in the base station 70) for at least the period of the
longest expected airtime (e.g.,
8 greater than five seconds for snowboarding, or greater than the period set
by the user).
Drop distance can also be determined through a drop distance sensor that
includes a
1 o plurality of accelerometers, such as shown in FIGS. 9 and 10. Through
integration of appropriate
11 acceleration vectors indicative of a user's movement perpendicular to the
ground, drop distance is
~ 2 determined. A double integration of accelerometers in the direction
perpendicular to ground (or
13 thereabouts) during an airtime period provides the correct signals to
determine skier height.
14 It should be apparent to those in the art that the accelerometers of FIGS.
9 and 10 provide
~ 5 sufficiently detailed information such that the entire sensing unit can be
mounted to a user of the
16 system directly, rather than onto a vehicle. With the scope of the
compensations described in
7 connection with FIG. 10, for example, movements of the human body, e.g.,
centripetal motions,
~ 8 may be compensated for to derive speed and/or airtime information that is
uncorrupted by the
19 user's movements. Such compensations, however, require powerful processing
capability.
2o Other features can also be determined in accord with the invention such as
through
21 measurements with the system of FIG. 10. For example, once you know your
starting velocity,
22 you can measure distance traveled and height above the ground by knowing
the air time for a
23 given jump. Other ways of doing this are by using accelerometers to
integrate the height distance.
24 The preferred way of determining distance is to know your velocity at the
jump start location,
25 such as described herein, and to use the airtime to establish a distance
traveled, since distance is
26 equal to velocity times time (or airtime).
27 For height, a sensing unit of the invention also determines height by
looking at the time to
28 reach the ground during an airtime. That is, once in the air, you are
accelerating towards the
29 ground at 9.81meters per second~2 (at sea level). The sensing unit thus
first determines the time
3o for which there is no more upwards movement (such as by using an
accelerometer or level sensor
31 that knows gravity direction and which changes directions at the peak, or
by using circuitry which
32 establishes this movement, or by determining the angle immediately prior to
launch to quantify a
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46
1 bias distance or time to a default measure), and then calculate the distance
traveled (in height) by
2 knowing that the default measure is equal to 1/2a t~2, where a is the
acceleration of gravity (9.81
3 m/s~2) and t is the airtime after the peak height is reached. If the person
does not travel upwards
4 or downwards at the start of a jump, then the height is simply 1/2at~2 where
t is the entire airtime.
A Doppler module can additionally provide height information; and thus a
Doppler
6 module can function as both a speed sensor 14a and a drop distance sensor
14c. Further, since the
7 impedance changes when a vehicle to which the Doppler module leaves the
ground, the Doppler
8 module can further function as an airtime sensor 14b. By sweeping the
frequency through various
9 frequencies, as known in the art, the signal frequency mix can be monitored
to determine altitude
relative to the direction of the antenna lobes (typically such Doppler systems
are used as
11 microwave ranging systems). Preferably, therefore, there are two antennas:
one to perform
12 Doppler speed, with high spatial accuracy in the antenna lobe so that speed
is achieved, and
13 another antenna to provide a lobe that roughly covers the ground area in
about a 60 degree cone
14 under the user so as to achieve first-return distance measurement. With
reference to FIG. 11, a
Doppler module 248 functions as the drop distance sensor and resides within a
sensing unit 250
16 mounted to a snowboard 252 (shown in the air, above the ground 254). The
radar or microwave
17 beam 256 from the module 248 extends in a cone 258 to adequately cover the
ground 254 so as to
~ s provide the correct measure of height on a first return bases (that is,
any portion of the beam 256
19 which first creates a Doppler signal sets the height; other height
measurements can alternatively
2o be used, including utilizing average return data). A cone 256 of angle ~
(e.g., 25-70 degrees in
21 solid angle) provides adequate coverage. The Doppler antenna signal fills
the conical beam 256
22 so as to determine drop distance from any orientation of the vehicle (i.e.,
the snowboard 252), so
23 long as that orientation relative to ground is less than the angle ~.
24 The Doppler module 248 may also be used as an airtime sensor since its
signal strength or
form changes when the vehicle 252 is off the ground. This change of signal is
thus detected by
26 the controller subsystem to determine airtime.
27 FIG. 12 shows a representative top view for one other snowboard constructed
in accord
28 with the invention. Specifically, a snowboard 270, with boot holder 271,
incorporates a sensing
29 unit 272 constructed according to the invention. The unit 272 has a display
274, a user interface
276 that provides a user with buttons to selectively access performance data,
as described above,
31 and one or more sensors 278 to provide data to the controller subsystem to
quantify performance
32 data. One sensor 278, for example, can include the Doppler module 248 of
FIG. 11.
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I FIG. 20 illustrates one embodiment of a bump skier 598 utilizing two power
sensing
2 units 600 in a mogul competition on a slope 612 (note that the skier is
grossly over-sized relative
3 to the slope 612, for purposes of illustration). One power sensing unit 600A
mounts to the ski 602
4 (or alternatively to the user's lower leg 604a), and another power sensing
unit 600B mounts or
attaches to the user's upper body 604. An RF signal generator 606 communicates
(via antenna
6 606a) the power values to a controller 607 (e.g., similar to the computer
and server 74, 82 of FIG.
7 1) at a base facility 608 (e.g., where the judges for the competition
reside). Those skilled in the
8 art should appreciate that one or both power sensing units 600 can
communicate the information
9 to the base 608, as shown; however, one power unit can also communicate to
the other power unit
I o so that one unit 600 communicates to the base 608. However, in either
case, an RF transmitter is
I I needed at each sensing unit 600 (similar to the data transmit section 22,
FIG. 1). Alternatively,
t2 other inter-power meter communication paths are needed, e.g., wiring, laser
or IR data paths, and
13 other techniques known to those in the art, such as discussed herein.
14 The combined signals from the units 600 provides a force differential
between the lower
~ 5 legs 604a and the upper body 604, giving an actual assessment of a
competitor's performance. A
16 computer 607 at the base station 608 divides one signal by the other to get
a ratio of the power
17 values measured by the two units 600 during the run. The units 600 start
transmitting data at the
18 starting gate 610 and continue to transmit data to the base 608 during the
whole run on the slope
19 612. The units 600 can also be coupled to the user via a microphone 614
(and wire 616) to
2o provide a hum or pitch which tells that user how effective his/her approach
is. Although it is not
21 shown, one or both units 600 have controller subsystems so as to enable the
features described in
22 connection with power sensing units herein. For example, a microprocessor
can be used to
23 provide a power measurement in "g's" for the competitor once she reaches
the base 608.
24 Those skilled in the art should appreciate that one of the units 600 can
alternatively
25 process the power values (e.g., divide the instantaneous power value of one
unit by the power
26 value of the second unit, to provide a ratio) generated by each of the
units and can transmit a ratio
27 of the values to the base station 608, rather than require the base station
to perform the
2s calculation.
29 One accelerometer-based vibration and shock measurement system (e.g., a
power sensing
3o unit) 620 of the invention is shown in FIG. 21. System 620 measures and
processes accelerations
31 associated with various impact sports and records the movement so that the
user can determine
32 how much shock and vibration was endured for the duration of the event. The
duration is
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1 determined with a simple start stop button 622, although duration can
alternatively start with an
2 automatic recording that is based on the measured acceleration floor (or by
an event such as
3 triggered by the start gate 600, FIG. 20)..
4 In system 620, vibrations and shock associated with skiing or exercise are
measured by
the use of an accelerometer 624 (or other motion or force-measuring device,
e.g., a microphone or
6 piezoelectric device) as the power sensor and of conditioning electronics
626 within the controller
7 subsystem. The accelerometer 624 typically is AC-coupled so that low
frequency accelerations,
8 or the acceleration due to gravity, are ignored. The accelerometer output is
then conditioned by
9 passing the signal through a band pass filter within the electronics 626 to
filter out the low
frequency outputs, such as the varying alignment to the gravity vector, as
well as the high
1 ~ frequency outputs due to electrical noise at a frequency outside the
performance of the
12 accelerometer 624. The resulting signal is one that has no DC component and
that is bipolar such
13 as the waveform shown in FIG. 22.
~ 4 The system 620 thus conditions the signal and remove the negative
components of the
waveform in FIG. 22. This is done, for example, by rectifying the output of
the bandpass signal.
16 Since a positive acceleration is likely to be accompanied by a negative of
the same area, the area
t 7 of the positive may be doubled to obtain the area of the positive and
negative. The signal may
18 also be processed by an absolute value circuit. This can be done via an
Operational Amplifier
19 circuit such as the one shown in the National Semiconductor Linear
Applications Data Book
Application Note AN-31, which is herein incorporated by reference. In accord
with certain
21 processes, known to those skilled in the art, positive values become
positive; and negative values
22 become positive. By way of example, the waveform of FIG. 22 is processed,
for example, to the
23 waveform of FIG. 23.
24 A unipolar waveform like the one shown in FIG. 23 is then integrated over
time by the
system 620 so that total acceleration is accumulated. This can also be
averaged to determine
26 average shock. The signal of FIG. 23 is therefore processed through an
integrator (within the
27 electronics 626 or the microprocessor 628) which will result in the signal
shown in FIG. 24. A
28 power value can then be displayed to a user via the display 630 (e.g., such
as the display 24c or
29 52, FIG.1).
The period of integration may be a day or simply a single run down a slope; or
it may be
31 manually started and stopped at the beginning and end of a workout. The
output is then be fed
32 into a logarithmic amplifier so that the dynamic range is compressed. The
logarithmic amplifier
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i can be provided within the microprocessor 628.
2 At any stage, the system 620 can be fed into an analog-to-digital converter
(such as within
3 the electronics 626) where signal processing is done digitally. The output
of the accelerometer
4 624 should anyway pass through an anti-abasing filter before being read by a
microprocessor
628. This filter is a low pass filter that ensures the highest frequency
component in the waveform
6 is less than half the sampling rate as determined by the Nyquist criteria.
7 The accelerometer 624 output can also be processed through an RMS circuit.
The Root
s Mean Square acceleration is then determined from the following formula:
z
1 f A2(t~t
0
to where T is the period of the measurement and A (t) is the instantaneous
accelerometer output at
1 t any time t. The period T may be varied by the user (i.e., to control the
power period) and the
12 output is a staircase where each staircase is of width T. This is then peak-
detected and the highest
13 RMS acceleration is stored; and an average acceleration and a histogram are
stored showing a
t 4 distribution of RMS accelerations. These histograms are displayed on a
Liquid Crystal graphical
display 630, for example, as a bargraph.
16 An alternate embodiment is to record the signal in time and transform the
signal to the
t'7 frequency domain by performing a Fourier transformation of the data (such
as within the
1 s electronics 626 or the microprocessor 628). The result is a distribution
of the accelerations as a
t 9 function of frequency which is then integrated to determine the total
signal energy contained
2o (preferably over a frequency range). The distribution is, again, plotted on
the LCD display 630.
21 Data may also be acquired by the accelerometer and telemetered to the
electronics 626 via
22 an RF link 631 back to a remote base 632 for storage and processing (e.g.,
such as at the base
23 station 70, FIG. 1). This enables ski centers to rent the accelerometer
system 620 which is then
24 placed on a ski (or snowboard) to record a day of activity. A printout can
also be provided to the
renter at the end of the day.
26 A separate memory module or data storage device 634 can also be used to
store a selected
27 amount of time data which can be uploaded at the end of the day. The data
can be uploaded itself
28 via a Infrared link readily available off the shelf, as well as through a
wire interface or through an
29 RF link 631.
3o The system 620 is particularly useful in impact sports that include
mountain biking,
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football, hockey, jogging and any aerobic activity, including volley-ball and
tennis. Low impact
2 aerobics have become an important tool in the quest for physical fitness
while reducing damage
3 to the joints, feet and skeletal frames of the exerciser. The system 620 can
be integrated within a
4 shoe and may thus be used by a jogger to evaluate different running shoes.
Alternatively, when
calibrated, the system 620 is useful to joggers who can gate it to serve as a
pedometer. The
addition of a capacitor sensor in the heel helps determine average weight. A
sensor for skin
7 resistivity may additionally be used to record pulse. The shoe can also
record the state of aerobic
s health for the jogger which is of significant interest to a person involved
in regular exercise. The
9 system 620 can also be used to indicate the gracefulness of a dancer while
they develop a
1 o particular dance routine. A football coach may place these systems 620 in
the helmets of the
11 players to record vibration and shock and use it as an indicator of effort,
or in the "football
12 blocking dummies" to quantify player effort.
t 3 In skiing, the system 620 has other uses since a skier glides down a
mountain slope and
14 encounters various obstructions to a smooth ride. Obstructions such as
moguls cause the skier to
bump and to induce shock. This shock can be measured by the accelerometer 624
and
16 accumulated in a memory 634 to keep a record of how much shock was
encountered on a
particular ski run. Exercisers may use such a system 620 to grade their
ability to avoid impact. A
18 jogger may use the system 620 to evaluate their gate and determine their
running efficiency. This
19 becomes important with a greater emphasis being placed on low impact
aerobics.
2o Those skilled in the art should appreciate that other improvements are
possible and
21 envisioned; and fall within the scope of the invention. For example, the
system 620 mounted on
22 a ski may be used to determine the total shock and vibration encountered by
a skier traveling
23 down a slope. Mounting an additional accelerometer 624 above the skier's
hip allows an isolation
24 measurement between upper torso and ski, as described above. This can be
used to determine
how well a trained skier becomes in navigating moguls. This measurement of the
isolation is
26 made by taking an average of the absolute value of the accelerations from
both accelerometers
27 624. The ratio of the two accelerations is used as a figure of merit or the
isolation index (i.e., the
28 ratio between two measurements such as on the ski and the torso, indicating
how well the mogul
29 skier is skiing and isolating knee movement from torso movement).
3o To avoid the complications of gravity affecting the measurements of system
620, a high
31 pass filter should be placed on the accelerometer output or within the
digital processor sampling
32 of the output. All analog signals should have antialiasing filters on their
outputs whose bandwidth
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1 is half the sampling frequency. Data from the accelerometers 624 is
preferably sampled
2 continuously while the circuits are enabled. The processor 628 may determine
that a ski run has
3 started by a rise in the acceleration noise floor above a preset trigger and
at a set duration. In
4 another embodiment, a table is generated within the processor of each
sufficiently high
acceleration recorded from the ski. The corresponding upper torso measurement
may also be
6 recorded along with the ratio of the two measurements. The user can
additionally display the n-
'7 bumpiest measurements taken from the skis and display the isolation index.
s
9 FIG. 25 shows a sport vehicle 700 (here shown as a snowboard) mounted with a
GPS
1 o sensor 702 (and antenna 702a) that is coupled to a controller subsystem
704 such as described
11 herein. The GPS sensor 702 serves the functions of one or more of the
sensors 14, FIG. 1. As
12 known in the art, GPS receivers such as the sensor 702 provide absolute
position in terms of
13 altitude and earth location. By monitoring the signal from the GPS sensor
702, speed, height and
14 loft time are directly determined. For example, at each signal measurement,
a difference is
calculated to determine movement of the vehicle 700; and that difference is
integrated to
16 determine absolute height off of the ground, distance traveled, speed
(i.e., the distance traveled
1'7 per sample period), and airtime. FIG. 25 thus illustrates a sensing unit
which includes a GPS
1 s sensor 702 (operating as one or more of airtime, speed and drop distance
sensors) and a controller
19 subsystem 704, such as the subsystem 12 of FIG. 1.
21 FIG. 47 illustrates one GPS-based system of the invention, including a GPS
receiver
22 1400 with an antenna 1401. The antenna is small because GPS operates at an
extremely high
23 frequency. The antenna 1401 may be mounted with a backback, of the user,
containing the
24 GPS receiver. The receiver is powered by a battery back 1402 which also
powers a
microprocessor 1403. The microprocessor 1403 takes data from the GPS receiver
1400 and
26 stores it as a position in random access memory RAM 1404. The data is
preprocessed
27 according to a program stored in Read Only Memeory ROM 1405. The processor
ROM 1405
28 can also contain stored maps with which to determine skier performance,
allowing the program
29 to become an expert system to for example identify trail features or
problems. The user
3o interfaces with the microprocessor 1403 via the peripheral interface 1406.
Examples of a
31 peripheral interface include keyboards, displays, etc. A panic button can
be included with the
32 interface 1406 to inform a base station of trouble. The warning is sent
with exact location so
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1 that the rescue team (e.g., the ski patrol) can easily find the stricken
person (e.g., skier).
2
3 An enhancement to the above system utilizes differential GPS. Differential
GPS makes
4 use of the property that a fixed receiver in a known position can be used in
conjunction with a
non-stationary GPS receiver with the effect that many of the large errors are
rejected. The
6 result is a more accurate position solution for the moving receiver. In the
preferred
7 embodiment, a user carries the reciever 1400 and the base station houses the
differential model,
8 as known in the art.
9
to For skiing and other similar sports, the user is given a GPS receiver and
an RF link
(e.g., a transmit section 22, FIG. 1) so that a central computer at the base
station lodge (e.g.,
12 station 70, FIG. 1) knows the location of every user. Such locations may
then be broadcast to
13 the skier for display in a set of goggles using heads-up displays.
14
FIG. 26 shows a strain gauge 720 connected to a controller subsystem 722, such
as the
16 subsystem 12 of FIG. 1. In the illustrated embodiment, the sport vehicle is
a ski or snowboard
1 ~ 724. Those skilled in the art understand that strain gauges can detect
stress associated with the
18 surface that the gauge is mounted upon. The gauge 720 thus senses when
there is little or no
19 stress on the snowboard 724, such as when the snowboard 724 is in the
"air"; and the subsystem
2o 722 then determines airtime from that relatively quiescent period. FIG. 26
thus illustrates a
21 sensing unit which includes a strain gauge 720 as an airtime sensor and a
controller subsystem
22 722. The sensing unit 720/722 can further provide factors such as power, by
utilizing the signal
23 generated by the strain gauge 720 as a measure of the punishment that the
user applies to the
24 vehicle 724. Accordingly, the gauge 720 can operate as a power sensor in
addition to an airtime
sensor.
26
27 In an alternative embodiment, the element 720 is a temperature gauge that
senses the
28 change in temperature when the ski 724 leaves the ground. This change of
temperature is
29 monitored for duration until it again returns to "in contact" temperature.
This duration is then
3o equated to "airtime" or some calibrated equivalent (due to thermal
impedance). Note that the
31 impedance of air is different from snow; and hence that change can also be
measured to
32 determine airtime.
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1
2 In an alternative embodiment, the element 720 is a load cell, known in the
art, such as a
3 strain gauge bridge, or other force-sensing means, such as force sensing
resistors (FSRs). A unit
4 incorporating such elements operates as described above.
6 FIG. 27 shows one speed, airtime and power sensing unit 740, constructed
according to
the teachings herein, and mounted to a sporting vehicle such as the ski 741.
The unit 740 has an
8 RF transmitter 742 (e.g., similar to section 22, FIG. l ) to communicate
signals from the unit 740
9 to a watch 744 worn by the user (not shown). In this manner, the user can
look at the watch 744
(nearly during some sporting activities) to monitor performance data in near-
real time. A small
1 t watch display 744a and internal memory 744b provide both display and
storage for future review.
12
13 The devices for measuring speed, airtime, drop distance and power as
described herein
14 can oftentimes be placed within another component such as a user's watch or
a ski pole. For
example, the power system 620 of FIG. 21 is readily placed within a watch such
as watch 744,
16 and without the unit 740, since power integration can be done from almost
anywhere connected
17 to the moving user. Likewise, airtime measurement through the absence of a
spectrum, such as
1 s shown in FIG. 6, can also be done in a watch or a ski pole. Speed
measurements, however, are
9 much more difficult if not impossible to do at these locations because of
the lack of certainty of
2o the direction of movement. However, with the increased performance and size
reductions of
2 ~ guidance systems with accelerometers (see FIGs. 9 and 10), even this can
be done.
22
23 FIG. 28 illustrates one drop distance sensing unit 800 for determining drop
distance
24 from a skier or snowboarder 801 (or other sport enthusiast, e.g., a
mountain biker,
skateboarder, roller-blader, etc.). The unit 800 includes an antenna 802 and a
GPS receiver 804.
26 The GPS receiver operates such as known in the art. Although the unit 800
is shown on the
27 skier's waist 806, the unit 800 can also be coupled to the snowboard 808 or
it can be
28 constructed integrally with the user's watch 810. In the embodiment shown,
the unit 800 can
29 include a second antenna 812 (or other data transfer mechanism, including
IR techniques)
' 3o which communicates with the watch 810 so as to send performance data
thereto.
31
A 32 FIG. 29 illustrates a block diagram of the drop distance sensing unit
800, including
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1 further detail therein. A microprocessor 809 connects with the GPS receiver
804 to process
2 GPS data. In particular, the GPS data is known to include three dimensional
data including
3 height off the earth's surface. The processor 809 thus processes the data at
predetermined
4 intervals, e.g., about 1 second or less, to determine the change of height
from the last
measurement. Accordingly, when airtime is determined, according to the
teachings herein, the
6 device 800 also determines drop distance for that interval. The drop
distance information is
7 stored in internal memory 812 so that it can be retrieved by the user or
transmitted to a data
8 unit such as the watch 810. Records of drop distance can also be stored
within the memory 812
9 such that a peak drop distance and a series of drop distances can be stored
and retrieved by the
to user at a later time. The device 800 also includes a battery 814 and other
interconnections and
1 I processing electronics (not shown) to operate the device 800 and to
provide drop distance data,
12 as described in connection with FIG. 1. A data transmit section 816 (e.g.,
the section 22, FIG.
13 1) transmits data via an antenna 816a (or other technique), as desired, to
the watch 810 or to
t4 other displays or data units, or to the base station, such as discussed
herein.
I5
16 Evaluation System
17
18 The sensing units described herein can be complex, and require lengthy
evaluation to
19 provide a robust system. To evaluate such units, a data evaluation system
was developed, as
2o described next. The data evaluation system provides a flexible data
recording unit that has
21 applicability in several circumstances where large amounts of data are
collected in adverse and
22 remote environments.
23
24 As shown in FIG. 30, the Data Acquisition system 899 includes five main
components on
25 a data acquisition/playboack board
26
27 ~ Data Recorder / Player 900
28 ~ PC Interface 902
29 ~ Analogue Motherboard 904
30 ~ Analogue Input Interface Boards 906
31 ~ Analogue Output Interface Boards 908
32
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To record information, the Data Recorder / Player board and Analogue Mother
Board 900,
2 populated with the required Analogue Input Interface Boards, are placed in a
box, connected by
3 a small back plane. Once the data has been recorded, the Data Recorder /
Playback Board 900
4 is removed from the box, and connected to the PC Interface board. The PC
then controls the
5 downloading of data to file.
6
7 The overall size of the Recording Package is 2-'/2" wide, 5-'/Z" deep, and 4-
'/2" tall. All
8 sensors are external, and may or may not be housed in boxes.
9
1o The data recorder and player 900, FIG. 31, is the heart of the system 899.
It includes a
11 block of memory 910 for holding the sampled data values, controlling logic
912, and interfaced
12 914a, 914b.
13
14 The Data Recorder / Player Board (DRPB) 900 always handles 32 bits of data.
It is
15 configured to either Record or Playback the data at a rate of one word (32
bits) every 15.6 S
16 (approx. 64KHz). The control interface 914 provides signal to interface to
the PC Interface
17 board and Analogue Mother Board.
18
19 The Control Logic 912 also provides refresh cycles for the dynamic RAMs.
The
2o Memory 910 consists of any 72-pin SIMM modules. These must be matched in
the same
21 manner as when used in a PC. (i.e. one 8Mb cannot be mixed with one l6Mb
module.) This
22 provides a limit of 512Mb of RAM, which will give a maximum of 134217728
samples. This
23 is equivalent to 34 minutes and 53 seconds. However, the larger SIMM's are
physically taller
24 than standard-sized devices and are very expensive. In practical terms, two
64Mb SIMMs
25 (128Mb) provide 8 minutes and 43 seconds of data recording at 64KHz.
26
27 The recorder can be paused during testing. Longer recording periods make
annotation
28 of the data (and data handling) more difficult. If this limit is
acceptable, two of the SIMM can
29 be removed from their sockets in the DRPB 900, to reduce its size.
31 The DRPB 900 has its own NiCAD battery (attached to the board for safety)
such that
32 the board can be removed from the box on the ski and taken to the PC for
downloading.
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2 PC Interface
3 The PC Interface 902 allows the DRPB 900 to be connected to the parallel
port of a PC.
4 It requires a bi-directional port (EPP). The design uses two MACH 210s, and
allows the PC to
control the upload and download process completely. The current download /
upload rate
6 achieved is 8 Mbytes / minute which is generally acceptable.
7
8 Analogue Mother Board
9 The Analogue Mother Board (AMB) 904 controls the sampling of the data on the
1 o Analogue Input Interface boards (AIIBs) 906. It presents the Data Recorder
/ Player 900 with
11 32 bits of data for each recording period. Data from the AIIBs 906 are
multiplexed. The
12 programming of the AMB 904 determines the sampling rates and position of
the data in the 32-
13 bit word for the AIIBs 906. If a different combination of AIIBs is
required, the AMB 904 is
t4 reprogrammed. Therefore, the control logic on the AMB 904 is held in an AMD
MACH 211
~5 which is a flash device, programmable whilst still on the board using a
JTAG connector. (thus
a notebook PC with a parallel port can reconfigure the board.)
17
18 As shown in FIG. 32, the Control Logic 912 inserts the real time clock 916
value into
19 one channel (probably an 8KHz channel). This will simply be a counter
counting at a minimum
2o frequency of 8KHz, which allows the analyzing software to detect when the
recording was
21 paused.
22
23 Analo ue Input Interface Boards
24 The Analogue Input Interface boards 906 are small daughter boards which
plug in
25 vertically to the Analogue Mother Board 904 (i.e., into the slots 918, FIG.
32). The Mother
26 board 904 will allow 8 of these boards to be connected at once. This design
allows an interface
27 board to suit the signal to be recorded. This is then combined with other
interface boards to
28 allow recording of a combination of signals, as required.
29
3o As shown in FIG. 33, the A/D converter 920 is a serial device; thus
reducing the
31 number of pins required and the level of board complexity. The board space
available for
32 Analogue Signal Conditioning 922 is limited. The Pressure Sensor AIIB 906
(i.e., that board
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1 incorporating a drop distance sensor, discussed above), shown schematically
in FIG. 34,
2 provides an example of the size limitations, and the complexity level
limitations on the
3 circuitry. Specifically, the circuit 930 of FIG. 34 is an example of an AIIB
906 for a SenSym
4 Pressure sensor. It uses four op-amps and various capacitors and resistors
to provide the
required signal conditioning.
6
7 FIG. 35 exemplifies a layout board 940 for circuit 930, FIG. 34, used to
connect to the
s AMB 904. The height of the board 940 is 0.9", and the width is approx. 2 '/z
inches.
9 Preferably, one AIIB 906 incorporates a Voice Annotation Channel, so that
data can be
annotated by voice concurrently with data acquisition. The AIIB 906 for the
Voice annotation
11 channel can have a simple tone generator connected to an external button
that is operated by
12 the skier. This will inject a tone when pressed onto the voice channel to
allow marking in the
13 annotation of special places.
14
The analog interface boards 908 are similar to the AIIBs, but have a DAC
rather than
16 ADC components. They allow the system to generate signals as recorded from
the sensors.
17 Thus a new board design can be tested on a virtual slope on the bench.
18
19 The data acquisition system thus permits the capture of data, real time, to
evaluate
2o sensors such as altimeters used in a drop distance sensor, described
herein. Two exemplary
21 altimeters, for example, are the SenSym SCX15AN Pressure sensor and the
SenSym
22 SCX30AN Pressure sensor.
23
24 As discussed herein, many embodiments of the invention utilize piezo foils,
such as
within airtime, power, and speed sensors. These foils for example include
those foils from
26 AMP Sensors, such as the AMP DTO-028K foil or the AMP LDT1-028K foil.
Similarly, an
27 accelerometer like the AMP ACH-O1-03 accelerometer can be used to generate
vibration data
2s (this sensor was in fact used to collect the data of FIG. 6).
29
3o Another pressure-based drop distance sensing unit 1000 of the invention is
shown in the
31 block diagram of FIG. 36. The unit 1000 includes a pressure sensor 1002, as
described above,
32 and is used to determine altitude. GPS, as described above, may also be
used in connection
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i with the unit 1000. The pressure sensor altimeter 1002 is used to determine
ambient pressure.
2 As altitude changes, so does the pressure. The pressure sensor 1002
indicates pressure by an
3 analog voltage. That voltage is conditioned by the conditioning electronics
1004 so that the
4 output data is filtered, well-behaved and has an appropriate scale factor.
The electronics 1004
also typically filter the signal to prevent aliasing when sampled by the
controller subsystem
6 1006. After conditioning, the data is converted to a digital word by A/D
electronics 1008 for
7 the microprocessor 1006. The data is thus represented as an eight, twelve or
sixteen bit word.
8 It is then read by the microprocessor 1006 and is interpreted as altitude.
9
to As illustrated in FIG. 37, the processor 1006 includes resident software
that schedules
t 1 the reading of data and its manipulation thereof. The core shell of
software is the Real Time
12 Operating System 1010. This may be purchased off the shelf by companies
such as Ready
13 Systems. These programs process tasks according to user selected priorities
so that every task
14 is executed within a software control frame. The part of the software that
reads the pressure
sensor output (from the A/D 1008') is called the Input Output Driver or I/O
Driver 1012. This
16 program may be executed on a regular basis automatically or may be the
result of an interrupt.
17 In the event of an Interrupt, the processor 1006 automatically launches an
interrupt service
18 routine or ISR. The purpose of an ISR and I/O Driver 1012 is to get the
data into the
19 processor's memory so that an application program may use the information.
Filtered by the
2o I/O Data 1013, the application 1014 is the software that interprets the
data, such as to
2 ~ determine altitude 1016. The data may then be stored in memory for other
applications 1014 to
22 operate on the data, use it for decision making, or pass it on to other I/O
Drivers for output.
23
24 The processing of altimeter data from the pressure sensor 1002 is a matter
of
eliminating the low and high frequency noise from the measurement. In this
embodiment, this
26 is done by cascading a high pass with a low pass filter. The Low pass
filter is selected by
27 determining the sampling rate and ensuring that the highest frequency
component in the signal
28 passed through the filter is half the sampling rate, known as the Nyquist
criteria. Frequencies
29 that are higher than half the sampling rate will result in aliasing. This
means that the spectrum
3o will be distorted and the original signal is not accurately reconstructed.
31
32 The high frequency component of the cascaded high pass, low pass filter is
thus
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selected by the maximum rate of descent the skier will travel. The higher the
low pass filter,
2 the faster the altimeter tracks the skier. Since the skier is limited by
inertia and kinematics (the
3 basic laws of motion) the rate of altimeter change is not high by signal
processing standards. If
4 a skier travels at 100 ft per second, this is about 68 miles per hour, which
means that if they
move along true vertical their altitude would be changing at 100 ft/sec. If
the change in output
6 voltage goes from DC to 100 Hz, then the low pass filter also needs to pass
the 100 Hz.
7
8 The low frequency of the high pass, low pass filter is related to how slow
the signal
9 changes. In this case it is limited by the frequency response of the
altimeter and the slow
1 o changes associated with atmospheric fluxuations.
11
12 FIG. 38 shows a "shock" or "G" or power digital watch 1020 constructed
according to
13 the invention. As in normal watches, a band 1022 secures the watch 1020 on
a user's wrist so
14 that the watch face 1024 can be viewed. A crystal 1026 provides the primary
window through
which to view data such as time on the display 1028. A user can adjust the
time through a knob
16 such as knob 1030.
17
s The watch 1020 also holds a power sensing unit 1032, as described herein.
The unit
19 1032 utilizes either its own microprocessor (e.g., a controller subsystem),
or augments the
2o existing microprocessor within the watch 1020 to provide like capability.
The unit 1032 is
21 controlled by interface buttons 1034a, 1034b, such as to provide ON/OFF
capability and to
22 display power performance data instead of time on the display 1028.
23
24 The watch 1020 of FIG. 38 thus provides "power" without the additional
mounting of a
2s sensing unit on a vehicle. Rather, this embodiment takes advantage of the
fact that many sports
26 include waving and movement of the user's arm (e.g., tennis and volley-
ball); and thus power
27 is determined through the techniques herein to inform the user of this
performance data,
28 through the watch 1020.
29
3o FIG. 39 illustrates another watch system 1040 for measuring power and
informing a
31 user of that power. As above, the watch 1042 is made to mount over the
user's wrist. The
32 watch 1040 functions as a normal watch, including, for example, a display
1044 to tell the user
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1 time (e.g., "10:42 PM"). Another portion of the watch includes a power
sensing unit 1045, a
2 processor 1048, force sensing element 1050 (e.g., a power sensor such as an
accelerometer, or
3 alternatively a microphone) and circuitry (not shown) to drive a display
that informs the user of
4 power. The processor 1048 processes the force data from the sensor 1050 and
sends a signal to
5 the display 1052 so that the user can see the power performance data (e.g.,
"50 G's"). The units
6 on the display 1052 need not be actual units, such as G's, but relative
units are acceptable to
calibrate to other users and to repeated activity by the same user. A control
knob 1054 provides
8 access to the unit 1045 in a manner similar to the user interface buttons of
FIG. I.
9 Those skilled in the art should appreciate that an altimeter can also be
placed in the
1o watch 1040 so that, as above, the user is informed of drop distance. The
button 1054 can also
11 enable control of the unit 1045 so that one of drop distance, or power, is
displayed on the
12 display 1052. This dual drop distance and power watch embodiment is
described in more detail
13 in FIG. 40.
14
i 5 FIG. 40 illustrates one block diagram of a power/pressure watch system
1060,
16 constructed according to the invention. An altitude or pressure sensor 1062
as discussed above
17 is conditioned by conditioning electronics 1064 which filter and scale the
sensor's output. The
I s data is then converted to digital by the Analog to Digital electronics
1064. The data is then read
19 by the microprocessor 1066, wherein the data is processed by software and
interpreted as
2o altitude. The watch includes a keyboard interface 1068 to set the time and
the different
21 performance data modes, as commanded by the user. Time is displayed on the
watch display
22 1070, as normal.
23
24 System 1060 can further include an accelerometer 1072 which senses
vibration and
25 shock, as described herein, and which provides a voltage that is
proportional to acceleration.
26 This output is then conditioned by the conditioning electronics 1074 for
scaling and filtering
27 (such as through a combination of low pass and high pass filtering): the
high frequencies limit
2s is selected by anti-aliasing requirements while the low frequency limit is
determined by low
29 frequency noise rejection. The data is then sampled by the analog to
digital electronics 1078
3o and read into the microprocessor 1066.
31
32 Drop distances may thus be determined by various sensors, including
accelerometers,
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1 differential Global Positioning System (GPS) receivers, and pressure
sensors, as discussed
2 above. These sensors may be used in conjunction with airtime logic - which
for example
3 senses the abrupt change in the vibratory noise floor, potentially
indicating the skier leaving
4 contact with the ground - to give useful drop distances corresponding to
airtime.
6 Accelerometers can also be used to determine airtime and the onset of free-
fall. By
7 using accelerometers to look at the ski vibration, airtime can be determined
by absence of the
8 vibrating spectrum, suggesting that the skis are no longer rubbing along the
ground. Generally,
9 this corresponds to the high frequency component to the acceleration signal.
Accelerometers in
1 o the prior art also measure the acceleration due to gravity, which tends to
change slowly. When
a body free-falls, the force on the seismic mass associated with the
accelerometer is zero
~ 2 because the seismic mass is no longer restrained. An accelerometer suite
that measures
13 acceleration in three translational directions will sum to zero in a free-
fall. When the gravity
14 acceleration returns, noted by the return of the low frequency acceleration
floor, as well as by
the return of the high frequency noise floor from skis rubbing on the ground,
the system can
16 determine the duration of free-fall - i.e., drop distance. The minimum
distance d traveled in
17 this free-fall along the axis of gravity known as true vertical may be
determined by the formula
1s d=vot +'/zgtz, where d is distance traveled downward, g is acceleration due
to gravity 32 ft/secz~~,
19 vo is the initial velocity downward, and t is the number of seconds of free-
fall. If the initial
2o velocity vo is not known then the minimum distance dm;~ can be determined
by the rest of the
21 equation dm;n = '/zgtz.
22
23 FIG. 9 showed the hardware block diagram for an accelerometer suite 207
capable of
24 determining loft and free fall. The diagram included three linear
accelerometers whose output
is conditioned by electronics that strengthen and filter the signals. The
output of the
26 conditioning electronics is then fed into interface electronics that
convert the signals from
27 analog to digital.
28
29 FIG. 41 illustrates a top view of one preferred system 1100 for determining
power
3o and/or airtime (and/or speed discussed in more detail below). The system
1100 includes a
31 sensing unit 1100a with housing 1102 mounted to a snowboard I 104
(alternatively, the system
32 1100 can be mounted to a ski, windsurfing board, bike, etc.) and a data
unit 1100b, such as a
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I data collection watch I 112 (such as the datawatch by Timex}. The housing
1102 forms an
2 enclosure for the sensor, here illustrated as a piezo strip 1108 such as
made by AMP Sensors,
3 in Pennsylvania. The strip I I08 connects with the housing 1102 to measure
sound within the
4 box 1102. The box 1102 thus serves to amplify the sound heard through the
ski 1104, and also
compresses air within the box 1102 in a manner that is indicative of the force
experienced by
6 the box and thus the ski 1104. Accordingly, the strip 1108 measures not only
sound, but a
'7 force-related factor that is used to determine power. In this manner, a
microphone (e.g, the strip
8 1108} is suitable to measure both airtime and power. Further, by monitoring
the pitch or signal
strength of the sound within the box, a speed can be correlated with the
sound. Accordingly, by
1 o a single microphone such as a piezo strip 1 I 08, airtime, power and speed
(or at least motion)
l I are provided. A controller subsystem 1110 connects to the strip 1108 to
process transducer
12 data; and that processed data is transferred, for example, to the watch I
112 worn by the user by
13 way of infrared energy signals from a diode/detector pair 1114a/b or other
similar optical data
14 transfer devices. The units 1100a and 1100b preferably permit communication
between units,
either direction.
16
17 Other transducers, e.g., an accelerometer or altimeter I 116 can also be
placed in the box
18 1102 for processing and transfer to the user's watch 1 I I2. The box I 102
is preferably sealed
19 against environmental effects so as to protect the electronics therein. It
is thus similar to the
2o housing 32 of FIG. 1. Because of the watch I 112, there is no separate need
for a display in the
21 sensing unit 1100a. A battery (not shown) powers the unit 1100a.
22
23 Another microphone such as the strip 1108a can also be included within the
unit 1100a
24 to provide additional speed sensing capability, as described below.
26 FIG. 42 illustrates that at the onset of airtime, the controller subsystem
can trigger a
27 drop distance calculation. Specifically, at an airtime sensed by an airtime
sensing unit, a drop
28 distance sensor - e.g., a GPS, altimiter, or accelerometer - is polled to
determine the change in
29 vertical direction. In the event of a vertical drop, the first derivative
in the z direction (True
3o Vertical) should be a maximum. The signal flow diagram of FIG. 42
illustrates this logic:
31
32 Specifically, loft condition is first determined by the airtime sensor of
block 1200. This
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i data state is determined, for example, by the sudden absence of noise in the
ski, causing an
2 abrupt change in the near noise floor. The next data state is characterized
by blocks 1202, 1204
3 and 1203. In state 1202 an altimeter is polled to determine if altitude is
changing at a high rate,
4 such as a rate associated with free fall. If so, the drop distance data is
accumulated for the
duration of the high free fall rate and the airtime. The state 1204 is similar
to that of 1202,
6 except for GPS receiver signals. In state 1204, GPS data is evaluated for a
high rate of change
7 in the Z direction. If there is a high free fall rate, the data is
accumulated for as long as both the
8 high rate and loft time are valid. The state 1203 corresponds to a data
state using accelerometer
9 data evaluation for airtime. As before, if the user is in free fall, the
accelerometer does not
I o experience an acceleration due to gravity. During this condition, drop
distance data is
I t accumulated during the airtime to determine vertical drop. The end of
airtime signifies the end
12 of the vertical drop, and state 1206 is returned. The distance of the drop
is provided by the
13 accumulation of the altimeter change, the change in GPS vertical height, or
the duration of the
14 accelerometer free fall and the laws of physics, as described herein.
IS
16 FIGS. 43 and 44 provide vibrational data corresponding to accelerometer
data at less
17 than 2mph, FIG. 43, and greater than 15-20mph, FIG. 44. The data
acquisition system was
18 the same as for the data of FIG. 6. As a ski moves faster over the surface
of the snow, more of
t 9 the energy from the spectrum is associated with the higher frequency
components. Specifically,
2o it is readily seen that the FIG. 44 has more power at higher frequency
components. By
21 segmenting and "binning" these frequencies, energy is isolated to such
frequencies so that it
22 can be compared to calibrated speed data at those frequencies. This is
described below.
23
24 Note first that a microphone can provide basically the same information as
the
25 accelerometer above (that is, the data of FIGs. 43 and 44 appear similar to
microphone data
26 taken within a unit such as described in connection with FIG. 41), at least
in frequency and
27 relative magnitudes. Microphones are cheaper than accelerometers, and thus
they are preferred
28 for production reasons.
29
3o With regard to FIG. 45, a force measuring sensor such as a microphone or
31 accelerometer generates a voltage signal indicative of the spectra such as
within FIGS. 43 and
. 32 44. This voltage 1300 is passed through an array of temporal filters
which "bin" the
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appropriate results, according to frequency, such as shown in block 1302. The
temporal
2 binning of block 1302 can include a series of analog networks that pass
specific frequencies
3 only. For each frequency bin, the data is processed by modules 1304: the
data is first rectified
4 at block 1306 and a capacitor 1308 charges over the time constant of an A/D
1310 to integrate
the signal of those frequencies; whereinafter the switch 1312 discharges in
time for the next
6 sample. The output is then summed according to frequency, for subsequent
summing.
7
8 Those skilled in the art should appreciate that the process of FIG. 45 can
be done
9 within a DSP, wherein the steps of blocks 1302 and 1304 are accomplished
through software
to modules. Accordingly, the unit 10 of FIG. 1 can thus simply process the
data 1300 within the
11 microprocessor 23a, or the logic functionality can be maintained in analog
such as within the
12 logic 12c or within other electronics not shown.
13
14 In any event, the various frequencies are then binned. For example, the low
frequency
0-1Hz is binned into the first bin, the 1-IOHz frequencies are in the next,
and so on (similar to
16 the equalizer light on the home stereo system). For each time T (set by the
A/D or other time -
17 which is preferably at a reasonably fast rate, e.g., 100Hz), the power in
each frequency is
18 integrated and assigned an integer value, such as: a typical value within 0-
1Hz is 1, a typical
19 value within 1-IOHz is l, and so on. These values are integrated at a user
selected interval (i.e.,
2o the power period). Further, the power values are preferably standardized to
every user, so if
21 you have 5 seconds of peak power activity, that will be saved - this number
should be
22 changeable to 10 seconds or even 1-5 minutes. A table created by this
technique might appear
23 as in Table I:
24
Table 1: Typical Frequency Binning, for Speed, Airtime and/or Power
Frequency 0-1Hz 1-IOHz 10-100Hz 100-100Hz
A/D Sample 1 .5 1 .1
1
A/D Sample 2 1 2 ,3
2
A/D Sample 1 2 1 .4
3
A/D Sample 2 1 3 .3
4
A/D Sample X1 X2 X3 X4
n
SUM over 6+...+X1 4.5+...+X2 7+...+X3 1.1+...+X4
time 1-n
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2
3 With time 1-n corresponding to the power period, power values are
functionally
dependent upon the SUM values, either within some or all of the bins. Note
that the bins of
5 FIG. 45 and Table 1 are chosen for illustrative purposes only; and that
other bin sizes and
ranges can be used in accord with the invention.
s Fortunately speed can also be determined through these SUMS (although the
summing
"period" should be much faster than for power, and should typically be less
than one second or
l0 even one tenth of a second). As noted above, there is a lot more high
frequency content at
t t faster speeds, FIG. 44, as compared to lower frequency content, FIG. 43.
So, speed can also be
12 correlated to such binned data, after obtaining a sufficient database of
samples (preferably
13 corresponding to the particular vehicle). Further, not all binning sections
need to be used in that
14 correlation. For example, one of the binning sections might readily produce
a four factor
15 increase of power for l ymph as compared to 3mph; and such increase is
repeatable to
16 correlated data.
17
18 Again, data for speed should not be integrated over time 1-n; but rather
should be
19 assessed for each sample or groupings of sample (e.g., an average of
samples over a 1/lOths
20 period). If for example a group of samples over any one second specify l
ymph data, then the
21 speed sensing unit should report "l ymph event recorded". If only one
sample has this value,
22 then it should be discarded since - relative to 1/lOs intervals - the speed
is substantially "steady
23 state". That is, an average of ten speed summations over one second should,
on average, all
24 report the same l5rnph event.
26 The data of Table 1 can be also used for power. In one preferred aspect,
power is a
27 factor which is scaled to the third derivative of vertical distance moved
with respect to time,
28 essentially the change of acceleration (in the perpendicular axis to the
ski or snowboard, if
29 desired, or some other orientation) as a function of time. Specifically,
power can be measured
as:
31
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s
aA
1 Power .~. a
at ~ ac
2
3 where x is distance moved in the selected direction (here, vertical to the
ski face), and A is
4 acceleration in the same axis.
6 In summary, selectable integral periods for power (e.g., S seconds, or 5
minutes, or
7 other user-selected power period), and for speed (e.g., less than one
second) are preferable, in
8 accord with the invention. Note also that the filter bank 1302 is preferably
adjustable and not
9 limited to 0-lHz, 1-IOHz, i0-SOHz, and 50-250Hz.
I 1 Note also that airtime can also be isolated from the data of Table 1. For
airtime, the low
12 frequency bins of 0-IHz and especially 1-IOHz will be very small; and the
controller
13 subsystem will immediately identify this loss of power, in these binned
frequencies. Since
14 airtime can be less than one second, the moving averages which integrate
the data should be
substantially less than the airtime minimum. Essentially, the airtime binning
is a one-
16 dimensional convolution between a rect function (defining the period) and
the data of the lower
17 frequency bins. A similar convolution can be applied to determine factors
such as power and
speed, except that the rect size is larger and different bins are likely used.
19
2o Power can be determined in other ways too, in accord with the invention.
Specifically,
21 power can be defined as the rate at which energy E is expended. Power and
work are related
22 by:
23
24 P=dE/dt
26 By having an estimate of the energy associated with the user's movement,
over time, then an
27 estimate is also available for the power expended by the user. The kinetic
energy of a simple
28 mass is expressed by:
29
3o E ='/2 m V2
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1
2 Thus energy is proportional to velocity squared. Velocity, or speed, is
deternZined in several
3 ways herein. For example, velocity can be determined from an accelerometer
by integrating
4 acceleration over time after subtracting the 1 g acceleration of gravity. In
a sampled system,
velocity at any point in time (at interval 0t) is equal to:
6
7 V ~ ~ ADt
8
9 where A is the measured acceleration with the 1 g acceleration removed.
Velocity is squared to
obtain a quantity proportional to the kinetic energy:
11
t2 E = V2
13
14 The total power over some finite time interval N is thus proportional to:
N ~T~
16 p~ 1 ~(vz-~z n
(N -1)Ot ;_,
17
18 If for example the accelerometer is attached to a ski or snowboard, then a
significant
19 portion of the measured acceleration may be due to the oscillations of the
ski/board at its
2o resonant frequencies. These oscillation are the ski/board's response to its
dynamic loading
21 environment and may not be indicative of the power that the skier/boarder
experiences. It is
22 therefore worthwhile to process the accelerometer signal so as to reduce
the contribution made
23 by ski/board vibration to the power measurement. The resonant frequencies
of the board and
24 skis are significantly higher than the dynamics that the skier's body
experiences. Thus, the
contribution of the ski/board resonant response to the accelerometer
measurement can be
26 reduced by applying a low pass temporal filter to the data prior to
integration.
27
28 One way of developing an algorithm to deal with extracting speed from
acceleration
29 data (or microphone data or other force sensing output) is through a neural
network. A neural
- 30 algorithm is one that is developed through a learning process, including
force sensing data
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1 from the sensor and speed data correlated during test. The neural algorithm
builds a network
2 that will process the data. It starts off by using a small number of samples
and a small number
3 of stages. The output is derived by weighting factors on the samples and
added together. The
4 output becomes a weighted average of the inputs, i.e., a multiple stage
moving average filter.
The output is then compared with the speed waveform and tested to see how well
it produces
6 the correct result. If the test fails, the number of samples is then
increased or the number of
7 stages is increased, or both. FIG. 48 illustrates an exemplary neural
network 1498 windowing
8 down acceleration data 1500 to achieve the correlated speed 1502.
Specifically, FIG. 48 shows
9 the construction of a network 1498 where four samples 1,2,3,4 are fed into
four stages 1504,
where each sample is multiplied by a weighting factor or gain. The network
1498 is then tested
11 to see if input data produces speed data. If not the number of samples used
as input are
12 increased as are the number of stages. At each network the relative gains
are also changed to
13 see if that will produce the required result.
14
Other Techniques for Speed Estimation
16
17 In accord with the invention, speed can also be determined based upon the
characteristics
18 of the resulting friction-induced noise spectra. When the vehicle - be it a
ski, snowboard,
19 waterski, etc. - passes over the surface, the spectra will have a bandwidth
content that increases
with vehicle speed in a deterministic fashion (if one can assumes that the
spatial spectral
21 content of the surface is invariant with respect to time and location). As
such, the following
22 describes a two-sensor technique for estimating delay times of transport
processes. The unit
23 1102 of FIG. 41 includes two such sensors - i.e., the two piezo strips 1108
- which are suitable
24 for such process measurements.
26 Consider the system 1600 depicted in FIG. 49. A ski or snowboard 1602 is
instrumented
27 with two vibration sensors 1604 such as described above. These sensors 1604
are attached a
28 distance "D" apart. The ski moves at a velocity "V" over the snow surface
1606. The front-
29 most sensor 1604a provides a vibrational output s2(t), a typical example of
which is plotted in
FIG. 50. The rear-most sensor 1604b provides a vibrational output sl(t),
plotted in FIG. 51.
31 Assuming that the characteristics of the snow surface 1606 which induce the
response s2(t) do
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not change significantly as the ski 1602 passes through a distance D, and that
the speed of the
2 ski 1602 does not vary significantly over that time, then sl(t) will
essentially be a replica of
3 s2(t), delayed by an amount of time i. This is seen by considering the
feature of the vibration
4 spectra at time tp in FIG. 50. This trace can be conceived of as " sliding"
along the time axis t
- 5 to produce FIG. 51, except now the aforementioned feature of the time
trace appears at time
6 t0+i.
7
8 If one estimates the time delay t accurately, then one simply uses the
relationship
9 DISTANCE = VELOCITY x TIME to infer the velocity V:
~~ - D
11 T . (1)
12
13 This same methodology has been applied in measuring the characteristic
propagation times
14 (and thence speeds) of spatial features in turbulent flow over wings and
other surfaces.
16 Since the vibrational input can be thought of in a local frame (the "
sensor frame" ) as a
17 random process, one can use conventional statistical means to infer the
delay time t, and thence
18 V. Typically, this is done using correlation functions. Define the cross
correlation function
19 R12(i) as
21 R~z~r)- T~m T ~~Sn~)S:~t + z)dt
(2)
22
23 A typical cross correlation function is plotted in FIG. 52 (note that this
cross correlation
24 function depicts a system with two characteristic time delays, tl and t2).
26 The most straightforward interpretations of cross correlation functions are
in the context
27 of propagation problems. For non-dispersive signal propagation of the type
considered here,
2s even in the presence of additive noise associated with the sensors, one can
show that
29
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1 Riz~T)= ~zC=- ~)
(3)
2
3 where R22 is the autocorreIation of s2(t). A typical autocorrelation
function is plotted in FIG.
4 53. Thus, the cross correlation of equation (2) will look like the
autocorreiation of s2(t) shifted
5 by the amount D/V along the correlation time axis. Using this fact, one can
readily infer the
6 delay time i by searching for the peak magnitude of the cross correlation
function (whose
7 construction is described below), and then computing the velocity V using
equation ( 1 ) since D
s is known. Thus, a two-sensor system will permit the measurement of the speed
V independent
9 of the spatial spectral content of the snow surface.
14
11 Note that the separation D is shown with large separation for purposes of
illustration;
12 when in fact that distance will typically reflect a small separation such
as illustrated by the
13 separation of the sensors 1108 of FIG. 41.
14
15 There are a few practical considerations to be kept in mind when computing
R,2, and in
16 interpreting its characteristics. First, unlike autocorrelations,
extraneous noise at the sensors
17 and 1604a, 1604b only reduces the relative contributions of individual
correlation peaks and
I8 increases the random error in the measurement; but it does not distort or
bias the result, hence
19 the time delay measured will be the true time delay. Secondly, one should
determine a priori if
2o there are any secondary propagation paths for the vibrational signal that
first enters sensor
21 1604a to reach sensor 1604b before the ski slides over the snow the
distance D.
22
23 This may occur in skis or snowboards, as is shown in FIG. 54. The board/ski
can support
24 bending modes via flexing, which have a characteristic (slowest)
propagation speed " CB" .
25 Also, the material within the board can support the equivalent of acoustic
(sound) waves within
26 it, with characteristic propagation speed CP. This would lead to a cross
correlation having two
27 correlation peaks, each of which corresponds to the delay time associated
with transmitting the
28 vibrational input at 1604a to sensor 1604b via bending and compressional
waves, respectively.
29 If these wave speeds are comparable with the skier's speed V, then one will
not distinguish
3o skiing speed from the natural vibrational response of the board/ski 1602.
Fortunately, these
31 vibrational wave speeds should be faster than the skier's speed, and thus
appear at a much
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1 shorter delay time on the correlation plot: The characteristic wave speed in
aluminum is 20,664
2 feet/sec, in ice about 10,496 feet/sec, and in rubber about 7872 feet/sec
for compressional
3 waves. The bending wave speed will typically be slower, but can only be
computed for well
4 known geometries and material compositions, and is usually easier to measure
in the lab
beforehand. If there should ever be a problem in measuring the speed V via the
cross
6 correlation of equation (2), it will likely be attributable to this. Should
that problem occur, one
7 can readily get around it by changing the sensor spacing D, which would
thence change i.
8
The cross correlation is computed from digital samples via
to
1 m_
1 1 Rn (~' ~~) = N - r ~ Sz~ Si .~, , (4)
12
13 where r defines the sample lag number at which the cross correlation is
being computed, N the
14 number of sample points in the time records, and the subscript n denotes
the r~-th element in the
time record, and 0t is the sampling rate of the system. This function can be
normalized to have
16 unit magnitude by dividing through by the square roots of the zero-delay
auto correlations of
17 the signals sl and s2 (e.g., the variances of these signals):
38
n,~ r or
19 p(rey)= Ri(0) Rz(0) (5)
23 for
22
23 a~ N ~ ~Sl'n~Z~ RZ N ~~52'~' 2 ~ (6)
24
This simplifies the setting of thresholds for selecting the delay time i
corresponding to the
26 skier speed V. Also, one can restrict the set of lag numbers r' if you
already have some idea of
27 the expected delays, given the speeds you expect to encounter skiing or
boarding (or other
28 sports, since these techniques apply to other sports and are discussed in
the context of skiing
. 29 for illustrative purposes only).
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2 The means to test this measurement and processing methodology is to mount
sensors on
3 the board or ski, and first measure the correlation function of equation (4)
for all r. Then,
4 compute the speed V per equation (1), and compare it to that measured with a
truth sensor,
such as a police radar gun, or a simple wind anemometer. Also, compute the
standard cross
6 spectra function as found on most any spectrum analyzer to see if the phase
of the cross spectra
7 denotes a pure lag (a progressive phase shift when unwrapped) over a range
of frequencies (as
8 would be expected here). This method though requires that you compute two
FFTs, do a
9 complex multiplication, and then compute the phase via an arctangent, all in
real-time. If you
1 o see several delay times in the cross correlation, as might be found for a
particularly floppy set
11 of skis with a very, very slow bending wave speed, move the sensors and see
if these peaks
12 shift so as to separate out the propagation delay due to skiing. The only
limitation here is the
13 spatial coherence length of the snow/board interface, which needs to be
observed
14 experimentally.
16 Regarding expected delays, consider the Table 2 of delay times (in msec)
for two
17 separations: D = 1.5 ft (as might be found in a foot-to-foot spacing on a
board), and D = 4 ft.
is The delay T1 corresponds to D = l.~ ft, and T2 corresponds to D = 4 ft.
19
2o Table 2: Delay processing times
sJoeed T1 msec T2 msec
5 204.5 545
10 102.2 272.7
15 68.2 181.8
20 51.2 136.5
25 41 109.3
30 34.1 90.7
35 29.2 77.9
21
22
23 This shows that to resolve the speed to within 5 mph, which represents one
suitable quantizer
24 for speed sensing for the invention, one needs to be able to resolve a time
delay at the higher
speeds of about 5 msec for the short baseline (D = 1.5 ft) case. To resolve
this with a finess of,
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i e.g., one part in 10, you must sample at 0.5 msec, which implies a bandwidth
of 2 kHz for the
2 short baseline system. This is not an onerous sampling requirement,
especially in view of
3 modern processing capability. Nonetheless, this is a 2 kHz sample rate on
two channels (i.e.,
4 for the two sensors), sampled with simultaneity better than 0.5 msec as well
(e.g., easily
achievable inter-channel skew, even for a system without simultaneous sample
and hold
6 amplifiers).
7
8 Another implementation issue is the fact that the system will lose tracking
during airtime,
9 or perhaps when carving an especially aggressive turn, especially in very
soft snow. Thus, it is
1 o preferably to implement a last estimate hold feature on the display of
speed information: if the
11 data is not good enough to update the speed (e.g., if the signals drop
below a certain level
12 indicative of air, if an air "trigger signal" is used as a conditional
trigger, or if the correlation
13 threshold level is not met), then continue to display the last value
measured.
14
Other speed measurement implementations are provided in FIGS. 55-57. In FIG.
55, the
16 two sensors 1604' are integrated beneath a snowboarder's boots 1622, or
even within the
boots' soles. In FIG. 56, a multiplicity of sensors 1604" is included with a
ski 1620 (showing
18 a binding 1622), and the cross correlation is computed across any pair so
as to maximize the
19 signal to noise ratio, or even to adapt to differing snow conditions or
skier speeds. In FIG. 57,
2o a two-dimensional array of sensors 1604"' is shown arranged around the boot
mounts 1640 of
21 a snowboard 1642, where one may employ either " s 1-s2" or " s3-s4" sensor
pairs to measure
22 V depending on which side of the board is dug in (so as to maximize the
sensor signals). One
23 may also employ either sl-s3 or s2-s4 to infer side-slip via correlation
measurements as well.
24
An alternative speed measuring system 1650 is shown in FIGs. 58 and 59,
incorporating
26 a down-looking Doppler system: system 1650 utilizes "bistatic" sonar, while
system 1650a
27 utilizes "monostatic". All of the transducers 1654 and their operating
frequencies are chosen
28 so that the resulting acoustic fields 1656 have wavelengths larger than the
transducer
29 diameters, making the radiation and receive patterns broad and overlapping.
The transmitter
{the "pinger" ) 1654a transmit a pulse, a CW signal, or a band-limited FM
signal, and the
31 receiver 1654b senses this signal and infesr speed from the associated
Doppler shift.
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1
2 The system in FIG. 59 is of particular interest, as it combines transmit and
receive
3 functions in a single element, reducing cost. Further, if one uses a pulsed
signal in this
4 configuration, then one could use it not only to sense Doppler, but distance
and height too (by
applying a time gate to the return). A near gate would be set to preclude
measuring random
6 hops and skips, but will instead see true "air" when the ski/board is
sufficiently high above the
7 snow. One rangefinding system manufactured by Polariod can function as such
a system, with
8 electronics for under $10.
9
1 o Other techniques for power estimation
11
12 Power can be used to quantitatively establish "bragging rights" among
users, allowing
13 them to compare level of effort expended during a run, over the course of a
day, etc.
14
Power is defined conventionally as the rate of energy transfer into or out of
a system. As
16 such, power is an instantaneous quantity, rather than an integrative
measure. Consequently,
17 power can be determined as that energy expended over a run, providing a
suitable metric to
18 measure and report.
19
2o There are three chief components leading to energy expenditure in sports
such as skiing
21 and snowboarding:
22 1. Frictional resistance as the vehicle moves across its supporting
surface, impeding the
23 motion of the vehicle
24 2. Air drag (both form drag and frictional resistance), impeding the motion
of the
vehicle/operator system
26 3. Supporting the operator upright in the presence of external forces, such
as those
27 encountered when skiing over moguls, riding a mountain bike over rough
terrain, or when
2s countering the pull of a tow rope when water skiing.
29
3o Frictional drag can be modeled in a variety of ways. Nominally, if the
resistance is
31 viscous in nature, then the retarding force is linearly proportional to the
vehicles speed V:
32
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1 F-c.V (1)
2
3 where "c" is the viscous drag coefficient, which should be determined
empirically. Note that
4 the frictional force is linearly proportional to the velocity V; while in
practice the
5 proportionality is nonlinear, the approximation will suffice for present
purposes. The linear
6 coefficient can also be estimated, measured or ignored (since power units
can be unitless and
7 preferably correspond to suitable numbers to compare multitudes of users in
an easy manner).
8 From conservation of energy,
9
10 2 mVz sine B= mg~J~- ~~ cVz (t)sin~ Bdt
11
12 where 8 is the angle of the slope, "m" is the mass of the user (e.g., skier
+ skis), and ~h is the
13 vertical drop between gates. Since the velocity profile is linear over
time,
14
15 ~'cV2(t)sin2 Bdt = 3c V2 sine 8t~
16
17 and thence
18
mV2sin2B~~
m~~ ~ 2
c=3I Vzsin2Bt
19 L J . (4)
21 With respect to the impact on energy expenditure during the activity, the
instantaneous power
22 loss is given by
23
P~(t) F,~(t)~ V(t)=cVz(t); vehicle in contact
24 ~0~ vehicle not in contact , (5)
26 Assuming that the frictional coefficient is constant over the run, then if
one measures V(t), as
27 discussed above or by some other estimation, then the total energy
expenditure due to friction
28 over a run is given by
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2 E~ _ ~'~, p,~(t)dt (6)
3
4 where tend is the finishing time.
s
6 The resistive force due to air frictional drag is in general proportional to
the square of the
7 velocity, hence the energy loss over a run will be proportional to the time
integral of this
8 resistive force times the velocity. The proportionality constant will in
general be difficult to
9 estimate, or even measure. However, roughly it is proportional to a constant
times the cross
l0 sectional (frontal) area of the user. One can get a first cut at this area
by assuming that the
11 width of a skier is a fixed proportion of their height, then from a
measurement of weight
12 (measured, for example, using the FSR means previously described) and a
standard actuarial
13 table for weight/height correlation. Thus,
14
E~ - ~~~~amV'(t)dt=~~~ m I~'(t;)~t
n ;_, (7)
i6
17 where "m" is the mass of the skier. The proportionality constant "a" is set
heuristically.
is
19 Finally, the contribution to energy expenditure from supporting the
operator upright in
2o the presence of external forces can be estimated using a system 1666 of
FIG. 60, where the
21 user 1670 wears an accelerometer 1671 around her waist, capable of
measuring the vertical
22 component of acceleration Dy(t). Further, the ski/board/boot sole 1672 has
a force measuring
23 means 1674 (as discussed herein) to measure the force component "F". The
operator 1670
24 will be dissipating energy by bending their knees, decelerating the mass of
their upper body.
Since the legs can be though of as rigid links with rotary springs at the knee
and hip joints, the
26 force due to this deceleration will be transmitted to the force sensing
means (springs transmit
27 forces). This, the instantaneous power dissipated in maintaining a tuck is
given by
28
p~ - F.~t ~, d dtt - F.~t~ ~ ~y~,~t)dt .
29
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77
Note that this equation is not conditional with respect to vehicle contact as
per equation (5) of
2 this section, as the reaction force F goes to zero when the vehicle leaves
the surface. The
3 energy expended over a run due to this effort is then given by
4
Eh - ~,~, F . ~ py"(t) dt,dt . ( )
J 9
6
7 In total, the energy expended over a run is given as the sum of the three
energy components:
8
E~~,~m = En + E~ + Eh . ( 10)
11 Alternate systems to measure the skier's hip position y(t) (shown in FIG.
60) is provided
12 in FIGS. 61 and 62. In FIG. 61, a flexible element 1680 is sewn into the
skier's pants 1682,
13 covering the leg 1684. A PVDF or NiTiNOL SMA strip 1686 is bonded to the
element 1680,
14 and will act as a large-area strain gage. When the skier bends his knees
the gage 1686 will
~ 5 stretch, and to first order this strain will be proportional to the change
in the leg's bend angle at
16 the knee. By differentiating this signal one can obtain a signal
proportional to the velocity y(t)
17 depicted above, but without using an accelerometer. Since one need not
integrate this signal to
18 compute velocity or displacement, the energy expenditure is computed simply
as a
19 multiplication.
21 Still another system for power measurement is shown in FIG. 62 In FIG. 62,
a force
22 gage or compressive strain element 1700 is inserted into the inside of a
tongue 1702 of a ski
23 boot 1704. When the skier leans forward, the force on the tongue 1702
increases to first order
24 in proportion to the angle of the lower leg with respect to the ski/board.
Thus, one can measure
a signal indicative of the quantity y(t) by measuring the force on the boot's
tongue. Once
26 again, since one need not integrate this signal to compute velocity or
displacement, the energy
27 expenditure is computed as a multiplication.
28
29 Other techniques for drop distance
31 In one aspect, instantaneous height above the surface (a relative rather
than an absolute
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1 measurement) is provided by the system of FIG. 59. By using a simple pulse
output sound
2 waveform, and applying a time gate to the acoustic return, the system can
sense the distance of
3 a skier/boarder above the ground from the round-trip time it takes the
signal to return to the
4 sensor. This provides a measure of the skier's instantaneous height.
6 Other techrtigues for airtime
7
8 Several alternative airtime sensors are next shown, including one new signal
processor to
9 detect transients to provide a "trigger" or "gate" for estimating airtime.
~ 1 With a FSR (Force Sensing Resistor) one can detect the presence of a skier
in the vehicle
12 (for instance, in the bindings if positioned beneath the boot and above the
binding), the skier's
13 weight, and whether the skier is being supported by a surface or is
"airborne" . A typical FSR
14 1800 is sketched in FIG. 63. FSRs can be purchased from IEE Interlink for
$2-$4 each in
small quantities depending on the aperture size. These pads consist of
interdigitated electrodes
16 1802 over a semi-conductive polymer ink 1804. The resistance between the
electrodes 1802
17 decreases nonlinearly as a function of applied compressive load, and they
exhibit high
18 sensitivity. A PSA layer is generally applied to one side; a further
encapsulant (say of
19 polyurethane) is desirable for a harsh/wet environments. A typical FSR
signal conditioning
circuit is shown in FIG. 64 that provides a voltage indicative of the FSR's
changing resistance.
21 Unlike accelerometers or induced-strain sensors (such as the AMP PVDF
sensors), FSRs sense
22 static loads.
23
24 Consider FIGS. 65 and 66. An FSR described above is placed in the load path
of the
skier, either beneath the boot 1808, within the boot's heel 1809, within the
ski/board, or
26 beneath the ski/board 1810. Consequently, when the skier 1812 stands on the
ski/board 1810,
27 and when the ski/board 1810 is on the ground, there is a reaction force FR
pushing up against
28 the skier 1812. This will be sensed by the FSR, as shown in FIG. 67, region
"A". When the
29 skier 1812 is pushed by bumps and moguls this force will change, as shown
in region "B",
FIG. 67, owing to Newton's second law. When the skier/boarder 1812 leaves the
ground, as
31 shown in FIG. 66, then region "C" is realized and reaction force diminishes
to zero as an
32 easily-sensed transient. This too will be sensed by the FSR, as suggested
in FIG. 67, region D
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of Trace I. Trace II of FIG. 67 is closer to zero force (if not actually equal
zero) and
2 corresponds to the case whereupon there is no residual compression of the
FSR due to the
3 clamping load of the binding, if the sensor is in the binding or boot heel
(or due to residual
4 mechanical stresses induced during manufacture if the sensor is embedded
within the
ski/board). Trace II, which shows a higher "residual" load, reflects when
these residual
6 stresses are present, and needs to be quantified if the transient amplitude
change in region "C"
7 is to be use as a trigger or gate to the airtime estimation. The
skier/boarder 1812 becomes
8 reacquainted with the supporting surface in region "E", as the reaction
force may now actually
9 peak owing to the compressional transient; this too is measured by the FSR
in the load path.
1 o The skier/boarder 1812 returns to " normal" travel again in region " F" .
11
12 The output of the FSR can in all liklihood be low-pass filtered at around
20Hz, since the
13 latency in estimating liftoff can be about 500 msec (i.e., a reasonable
minimum airtime lower
~4 limit). Trigger generation is effected using only a comparator or similar
analog thresholding
electronics based upon signal amplitude, and perhaps slew rate or hysteresis
(probably not
16 necessary); and there is no need to measure spectral changes.
Unfortunately, FSRs do not have
17 significant bandwidth and thus can limit the measurable vehicle speed.
18
19 In the user of PVDFs (i.e., the piezo foils discussed above), certain care
should be taken.
2o First, they are only capable of measuring dynamic signals: they will not
measure a static load,
21 or a static displacement. For static measurements (such as inferring weight
as described above)
22 or very low frequency measurements (typically below 5 to 10 Hz), other
sensors should be
23 employed such as FSRs.
24
A second performance limitation of the PVDF is that these sensors are far more
sensitive
26 to induced in-plane strains than to compressional strains. These strain
axes 1-3 are defined in
27 FIG. 68, showing one piezo foil 1900. The in-plane strains are in the " 1"
and "2" directions,
28 with the " I" direction being the "pull" direction for the PVDF (almost
always the long axis
29 for the AMP sensing strips) associated with the material's processing. The
compressional
strain is in the "3" direction. Note that the electro-mechanical constituitive
constants relating
31 an input strain to an output voltage measured across the thickness of the
sensor (where the
32 electrodes are always placed) are approximately an order of magnitude
larger in the " 1"
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1 direction than in the "3" direction; while the values in the "2" and "3"
directions are
2 approximately equal. This is an artifact of the fabrication methodology for
so-called
3 "uniaxial" PVDF. Consequently, this makes the AMP PVDF strips excellent
dynamic strain
4 gages.
5
6 This enhanced strain performance is not a problem if the sensor strip is
attached to a
'7 rigid, non-bending surface, as suggested above (e.g., the housing 32, FIG.
1). In this
8 configuration the piezo is rigidly glued to an inflexible surface 1910, FIG.
69, and a rigid mass
9 M is attached to the top of the piezo 1912. Consequently, when the lower
surface is vibrated,
1 o the mass M causes the piezo 1912 to compress owing to the inertial forces,
leading to a
11 voltage output 0V across the sensor's thickness proportional to the
vibration, which is
12 essentially how an accelerometer works.
13
Consider a piezo strip 1920 attached to a flexible surface, as suggested in
FIG. 70. When
15 the surface bends in response to an input vibration, this induces an output
in the sensor 0V
16 proportional to the bending strain. The vibration need not accelerate the
mass M in the vertical
07 direction to induce this output; so, if the surface is a ski, and the ski
flexes irrespective of
18 whether or not the ski is accelerated vertically, you will measure an
output that will typically
19 swamp any signal due to vertical acceleration or vibration. In this
situation, you are measuring
2o the flexural response of the ski, and not the vertical vibration induced by
the ski's passage over
21 a rough surface. In order to measure this vertical vibration, one needs to
deconvolve the ski's
22 flexural dynamics, a significant challenge. Note also that the ski itself
is acting as a filter, since
23 it has natural modes of response much like a guitar string or drum head,
and very much wants
24 to respond at those frequencies. This will skew and perhaps dominate any
measurement of the
25 vibrational spectra.
26
27 These problems are addressed in FIGS. 71 and 72. Consider a ski or
snowboard having
28 two PVDF sensors deposited on it, one atop the ski and one below (or any
symmetric
29 arrangement about the midline of the ski/board), registered spatially one
above the other.
3o These are laid up with their polarization axes aligned, as suggested by the
arrows in FIGs.
3 t 71,72. In FIG. 71, the ski bends, and the top sensor sees a compressive
strain, while the lower
32 sees an extensive strain. Thus, charge will migrate to the outer surfaces
of both piezos. If one
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1 measures the voltage potential across these two sensors the result will be
(ideally) zero; the
2 same is true for bending in the opposite direction, for higher-order modes,
etc. In practice, the
3 bending strain response is significantly diminished, with residual response
due to mis-matched
4 sensors and positioning errors. One can think of this arrangement as
providing "common
mode rejection" for bending strains. In FIG. 72, if a compressive stress is
applied as from a
6 vertical acceleration of the ski owing to its passage over an irregular
surface then a potential
7 difference is induced over the outer layers of the sensor composite, and a
voltage V is
s measured.
9
to An alternate means of achieving an analogous result on one side of the
vehicle is to build
11 a sandwich of two PVDF layers, as shown in FIG. 73. Here, the polarization
axes are aligned
12 in opposition. Unlike the previous embodiment, this arrangement's voltage
output is measured
13 via the connections shown at the left side 1980 of the sensor 1982, which
tap both the inner and
14 outer electrodes of the piezo composite. This arrangement has proven to
yield a superior
acoustic receiver, and provides common mode rejection to electrical
interference such as from
16 radio transmitters.
17
18 For both embodiments of FIGS. 71/72 and 73, one can employ a voltage-
follower circuit
19 to drive long leads, if required.
21 FIG. 74 illustrates a gaming system 2200 which connects several mountains
2202a-
22 2202c via a WAN or the Internet 2208. A plurality skier or snowboarder 2204
are on the
23 mountains 2202; and each has a data transmitting device 2206 (the device is
illustrated in FIG.
24 75); and each device 2206 includes functionality such as described herein
to provide
performance data. In particular, each device 2206 includes a microprocessor
2208 (or
26 microcontroller or other intelligence sufficient to assist in acquiring
data from connected
27 transducers) and can include one of the following: airtime sensor 2210a,
speed sensor 2210b,
28 power sensor 2210c and drop distance sensor 2210d. If required, a battery
drives the device
29 2206. The microprocessor 2208 collects data from one or more sensors 2210
(note that sensors
3o 2210 can be simple transducers connected through conditioning electronics
2212), processes
3 t the data, and transmits the data to a data driver 2214, such as data
section 22, FIG. 1. The data
' 32 driver 2214 communicates with receivers (e.g., the receiver 72) at each
respective lodge 2220a-
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82
1 1220c so that the data is available on the Internet 2208. In this manner,
data from any mountain
2 is collected for comparison to other players on other mountains. A main
database 2222 keesp
3 and stores all data for access through the Internet 2208. For example, the
database 2222 can
4 include a WWW interface which all can access (if desired, or only if give
access authority) to
acquire and compare scores across the nation (or world).
6
7 Note that the game played by the system 2200 can be for airtime, speed,
power, or drop
8 distance, or a combination of one or more. Further, it should be understood
that the medium of
9 skiing is shown illustratively, and that other sports are easily
accomplished in a similar system.
1 o By way of example, each person 2204 could be a mountain biker instead. Or,
each mountain
11 could be replaced by a lake or ocean and each person 2204 can be a
windsurfer.
12
13 Certain devices of the invention can also be incorporated into a boot
binding, such as
14 shown in FIGS. 76 and 77. In FIG. 76, a binding 2300 is shown; while in
FIG. 77, a
snowboarder binding 2302 is shown. In each case, a sensing unit 2304 such as
described above
16 is incorporated into the binding. The device 2304 can include, for example,
an airtime device
17 and/or a power sensor and/or a pitch-based speed sensor and/or an
altimeter. A data transfer
18 unit 2306 (e.g., a radio, inductive loop, IR transmitter) connects to the
unit 2304 so that data
19 (e.g., airtime, power, speed and drop distance) can be relayed to the user
{or to a data unit or to
2o the base station). For example, the user carries a sister data receive unit
(not shown) that
21 provides the user with the desired data. Note that data transfer unit can
be an IR transmitting
22 section and the receive data unit can be a datawatch, such as described
above. The device 2304
23 includes power and other circuitry so as to operate and acquire the
appropriate data, as
24 described above.
26 The advantage of the design of FIG. 76 is that a sensing unit according to
the
27 invention is not mounted directly on the ski (or snowboard) and is further
protected from the
28 environment. Also, it is more practical to mounting to a board or ski.
Without such packaging
29 advantage, it is difficult, though not impossible, to package a sensing
unit (such as an air meter
or speed meter, described herein) onto a board with sufficiently small size
and weight.
31 Preferably, a device such as the device 1102 of FIG. 41 has only a depth of
0.300" or less, and
32 an overall weight of less than 1 /8 to 1 /4 pound. Such a size is preferred
in order to fit the
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83
1 device into a recessed area on the board without excessive overhang or add-
on weight.
2 However, as in FIG. 77, this goal is relaxed somewhat.
3
4 Power can also be determined by other methods, in accord with the invention.
For
example, with an accelerometer pointed up, relative to the ski and
perpendicular to the ground,
6 when the user hits bumpy terrain, the accelerometer will have "peaks" and
valleys. One
7 technique for determining power is thus to count peaks past some
predetermined threshold,
8 such as shown in FIG. 78, which illustrates "5" peak signals which pass the
threshold "k". The
9 value "5" does not have to correspond to a real unit, such as g's. The value
of k can be set
o experimentally such as through the data unit described above. k should be
above 1 G, for
t t example, which is a constant force. That is, when the accelerometer is not
pointed along the
12 gravity vector, it might read "0" and.will read "1" - and neither event
should effect the power
13 calculation. Alternatively, an exact determination of g's can be made and
provided by the
14 sensor, and thus given to the user. However, this requires extensive
processing and is not
~ 5 overly practical. The goal here is to display units that are common to
all. For example, power
16 units could extend from 0-10 (or 0-100) wherein, for example, a user with a
9 shows great
17 exertion as compared to a user with a "1" reading (or alternatively, a 70
as compared to a 10
~ 8 reading). It is thus important to make the power determination at
appropriate intervals, or at a
19 set integration time.
2 t FIG. 79 shows a sensor 2499 such as described herein including a doppler
module
22 2500. The beam from the module 2500 extends backwards, or forwards, on the
ski (or
23 snowboard) 1506 and about 45 degrees to the side. In this manner, the beam
2502 need not
24 extend through the board, such as described above; but can instead broadly
illuminate a region
2504 away from the ski 2506. Since the module 2500 is slightly above the
board, it can
26 illuminate the region 2504 without going through the board 2506. This
greatly assists taking
27 such measurements, for example, in the ultrasound region since ultrasound
does not transmit
28 through boards well. Similarly, for microwave, metal in the board can
completely wipe out a
29 signal return, effectively eliminating the speed measurement.
31 It should be noted that a power sensing unit can be made generically and
simply on a
32 wrist watch, as discussed above. Such a unit is useful for various sports,
such as basketball, to
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84
1 monitor a user's aggressiveness in play. As shown in FIG. 80, such a unit in
the form of a
2 watch 2600 can provide data to a computer 2602 at the gaming site (FIG. 80
shows one user
3 on a basketball court, for example; though the scene is equally applicable
to other sports, e.g.,
4 soccer, football and hockey). The computer 2602 and watch 2600 have data
transfer capability
such as through RF signals, known to those in the art. During play, the user
2604 is effectively
6 "monitored" so that the coach or owner can effectively gauge performance and
aggressiveness.
7 The device within the watch 2600 can include sensors such as described
herein. The watch
8 2600 further includes batteries and required circuitry.
9
to The unit 2600' could also be placed and/or sewn into a user's shorts, as
shown in FIG.
11 81.
12
13 Certain sensing units of the invention require power. Often it is desirable
to turn the
14 power off when the unit is not in use, such as when the user is in a bar.
In accord with the
invention, a FET switch can be used for this purpose, such as known in the
art. This saves
16 battery life.
17
18 Power and/or speed can also be measured and assessed by measuring signal
PSD.
19
Barometers and altimeters, in accord with the invention, preferably "logic"
out data at
21 the base and peak of a mountain, so that data is not stored and recorded in
these regions. This is
22 similar to logic out regions such as airtime above 30 seconds, which likely
does not occur, or
23 for less than 1 second (or 2 second) which resembles walking and which
should be ignored.
24
Note, if there is no airtime, often, the circuitry of the invention should
operate to logic
26 out drop distance too, such as shown in FIG. 82.
27
28 FIG. 83 illustrates one other embodiment wherein data from a sensor 2699
such as
29 described herein (e.g., a sensor such as an airtime sensor) transmits data
to a user 2700 at the
user's helmet 2702. A heads-up display 2704 and/or a microphone 2706 can be
used to relay
31 performance data to the user 2700, for example by informing the user of
"airtime". If the user
32 is a speed skier, the data is useful to modify form since they do not wish
airtime. A base station
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1 computer can also monitor the airtime data which can then be evaluated
later. A buzz sent to
2 the mic 2706 can similarly inform the user 1700. The heads-up display 2704
can take the form
3 of sunglasses; and the helmet 2702 is not required.
4
5 Sensing units of the invention can be integrated within many sports
implements, such
6 as shown in FIG. 84. Each implement of FIG. 84 includes a sensing unit 3000,
described
herein. The implements include, at least, ice skates 3002, water skis 3004 (or
wakeboards
8 3004); ski poles 3006, windsurfer 3008, surfboard 3010, tennis racquet 3012,
skateboard 3014,
9 roller blade 3016, and volleyball 3018. Other implements are within the
scope of the invention.
to
11 Those skilled in the art should appreciate that changes can be made within
the
12 description above without departing from the scope of the invention. For
example, different
13 lenslet array configurations, materials, and applications are easily made
and envisioned.
14
15 The invention thus attains the objects set forth above, among those
apparent from
16 preceding description. Since certain changes may be made in the above
apparatus and methods
17 without departing from the scope of the invention, it is intended that all
matter contained in the
18 above description or shown in the accompanying drawing be interpreted as
illustrative and not
19 in a limiting sense.
21 It is also to be understood that the following claims are to cover all
generic and specific
22 features of the invention described herein, and all statements of the scope
of the invention
23 which, as a matter of language, might be said to fall there between.
24
Having described the invention, what is claimed is:
26
