Note: Descriptions are shown in the official language in which they were submitted.
~2~7~3
MOTION_DISCONTINUANCE DETECTION SYSTEM AND METHOD
BACKGROUND OF THE INVENTION
The present invention relates to electrical systems
controlled by motions of objects, for instance, electrical
load switches, traffic lights, etc.
Various systems are already known in the prior art
for detection of motion in a particular field of view. These
systems include optical, ultrasonic, electromagnetic, and
electrostatic, among other methods. All of these differ by
the accuracy, reliability of detection, and cost of manufac-
ture and installation. All of these systems are intended to
detect motion and, determined by such detection of motionl to
control appropriate electrical devices. However r up to the
present time, no adequate equipment has been proposed for
electrical switches. One of the reasons for this is the
relatively complicated construction of known motion detec-
tors, and a common purpose among all of these prior art
systems is that they are used to detect the presence of
motion.
U.S. patent 2,016,036, for example, disclosed a
photoelectric system which utilized a grating disposed in
front of each of two photoelectric cells so that the two
photoelectric cells were affected differently by the motion
of an object in the field of view, and hence, even though
there was considerable ambient light, the motion of objects
could be detected.
U.S. patent 2,142,378 utili~ed two photoelectric
tubes with the light from a given field of view falling
alternately on the two tubes by means of apertured light~
~2~7~63
intercepting screens. By this means, the speed and direction
of movement of an object could be determined.
U.S. patent 2,774,961 discloses a moving object
indicator which utilizes two optical density wedges having
continuous density gradations. Liyht from a ~ield of view
passes through these wedges to two separate photocells, which
are connected in a bridge circuit. The brid~e is normally
balanced so that if there is no movement of ~he objects,
there is no output from the movin~ object indicator. When a
movin~ object is detected, this unbalances the bridge to pro-
vide an electrical output.
UOS. patent 3,972,021 discloses a field of view
scanned by a pair of lenses and a beam splitter to illuminate
a plurality of photoelectric detectors. The system detects
the presence of motion within the field of view.
All of these known systems are relatively compli-
cated, and are systems having a construction which detects
the presence of motion of objects within the ~ield of view.
The problem to be solved, there~ore, is how to
construct a system and the method of operation of a system
which will determine when a person has left a room, thus
de-ener~izing the lights in the room or some electrical
appliance such as an electric soldering iron or an electric
typewriter within the room.
Further, all known photodetectors and adjusta~le
switches require a power supply independent of the power line
to the load. This mak~s wiring more complicated and in-
creases production and installation costs. The problem to be
solved, therefore, includes how to establish a photodetector
system which does not require any independent power supplyO
3.;2~ 3
SUMMARY O~ T~E INVENTION
This problem is solved by a detection system for
d~termining the discontinuation of motion, comprising in com-
bination an electrical circuit having a detector and photo-
sensitive means, imaging means to establish illumination on
said photosensitive means from a given field of view, image
distortion means included in one of said imaging means and
said photosensitive means to establish nonuniform electrical
output of said photosensitive means upon motion of objects in
said given field of view effecting a change in illumination
on said photosensitive means, timer means connected to close
load switch means and having an input from said detector,
said timer means having a given time period at the expiration
of which said load switch means are opened unless said timer
means is reactiYated during said given time period~ and means
connecting the output of said photosensitive means to said
detector to detect a change in illumination on said photo-
sensitive means to reactivate said timer means.
The problem is further solved by a motion detection
system, comprising, in combination, an electrical circuit
having a detector connected to the output of photosensitive
means, imaging means to establish illumination on said photo-
sensitive means from a given field of view, image distortion
means included .in one of said imaying means and said photo-
sensitive means to establish nonuniform electrical output of
said photosensitive means upon motion of objects in said
given field of view, a housing for said electrical circuit,
shield means in said housing establishing at least a part of
said given field of view and shielding said photosensitive
means from direct illumination from electrical illuminating
means of said field or view, and timer means connected to the
output of said deteotor adapted to maintain energization of
the terminals of the illuminatiny means upon motion of
~7~63
objects in said given field of view and de-energization of
the terminals of the illumination means upon passage of a
given time period subsequent to discontinuance of motion of
objects in sai~ given field of view.
The problem is further solved by the method of
utilizing imaging means, photosensitive means, and a timer
for determining an appropriate time to ~e-energize an elec-
trical load usable in the presence of humans in a room, said
method comprising the steps of establishing the light re-
flected by obj~cts in a given field of view in the room to be
directed by the imaging means tc illuminate the photosensi-
tive means, providing image distortion means to establish
nonuniform illumination of said photosensitive means upon
motion of objects in said given field of view, and connecting
the timer to the photosensitive means and to terminals of the
electrical load to establish continued energization to the
electrical load terminals upon detection of motion in said
given field of view and to establish de-energization of the
electrical load terminals upon the passing of a given period
of time subsequent to the discontinuation of motion in said
given field of view.
An object of the invention, therefore, is to detect
the discontinuance of motion within a room in order to turn
off the lights in the room.
Another object of the invention is to provide a
motion discontinuance detector which will control, through a
timer, an electrical load.
A further object of the invention is to provide a
photosensitive system which supplies its own power from the
voltage supply terminals.
A still further object of the invention is to pro-
vide an apparatus which will function with at least the same
accuracy in detecting motion as heretofore obtainable in the
prior art devices~ but which has simpler circuitry which does
~Z~ 3
not re~uire tuning and which can be easily manufactured and
installed at an appreciably lower cost.
Another object of the invention is to provide a
motion detector combined with an electrical switch in order
to control power flow by detecting motions of the objects.
Another object of the invention is to provide a cir-
cuit which obtains power for the motion detector and switch
directly from the load power supply terminals in order to use
the proposed system instead of a conventional electromechani-
cal switch without requiring an a~ditional pOW2r line for the
operation of the motion detector system.
Accordingly, the present system is characterized by
a motion detector of any desired construction, with the out-
put thereof being connected directly or indirectly to the
restarting input of a timing circuit. An output of the tim-
ing circuit is used to control various systems utilizing the
fact of discontinuance of motion. The timing circuit mea-
sures a given time interval, and it is returned to the start
of such interval by every output signal of the motion detec-
tor. Upon the timing circuit's timing out t an output signal
is given which indieates that there has been a discontinuance
of mo~ion detected in the motion detector's field of view
during a predetermined time interval. This means the present
system produces an output signal change upon the discontin-
uance of ~otion, not by the presence of motion.
A feature of the present invention is ~o provide
simple and inexpensive motion deteetors which can be effec-
tively utilized even in sueh common devices as wall switches
for electrie lights in a room.
The system deseribed in the present application
utili~es a solid state switch, sueh as a thyristor, a reverse
blocking triode thyristor, or bidirectional triode thy-
ristor. Therefore, the load is connected in series with such
thyristor. Each sueh thyristor has a voltage drop across the
7863
main terminals while the power is on. This drop in voltage
may be enhanced by an additional threshold device, for
example, a Zener diode, in series with the gate, and the
voltage developed by such voltage drop is sufficient to sup-
ply energy to the motion detector electrical eircuit. In
sueh a case, the control system and solid state switches are
both connected in series with respect to the load, and con-
sume energy only when the load is energized. The series con-
nection does not require an additional power line to the
electrical motion detector cireuit, as it would if it were
connected in parallel, and therefore the motion-eontrolled
switch can be used as a direet replaeement for any eonven-
tional switeh, e.g.~ a wall switch~ etc. The present inven-
tion is therefore applieable in a broad field of energy eon-
servationr for e~ample, turning off the lights in a nonoceu-
pied room of a dwelling.
Other objects and a fuller understanding of the
invention may be had by referring to the following deserip-
tion and elaims, taken in conjunetion with the aeompanying
drawings.
3LZ~863
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an electrical circuit diagram of the
motion-controlled switch;
FIG. 2 is a voltage-versus-time diagram of the
voltages available in the circuit;
FIG. 3 is a schematic bloc~ diagram of a modifica-
tion of the invention;
FIG. 4 is an elevational view of a screen having
pinholes;
FI~. 5 is an isometric view of the housing for a
wall switch and photosensitive detector; and
FIG. 6 is an isometric view of a housing for a
desk-mounted motion discontinuance controlled switch;
FIG. 7 is a schematic diagram oE the preferred
embodiment of the main portion of the electrical circuit;
FIG. 8 is a schematic diagram of the circuit of FIG.
7 connected in a wall switch assem~ly; and
FIG. 9 is a schemat,ic diagram of the circuit of F~G,
7 connected in a desk-top switch assembly.
DE~CRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is directed to a motion
discontinuance detector system and method utilizing a motion
detector 11. This detector 11 has an output signal which is
present so long as moving objects are present in the field of
view. .~s an example, in a living room, people cannot remain
without any motion for any substantial period of time, for
example five minutes. The motion detector 11, combined with
a timer, can produce in this case an output signal, for
~Z~7~363
example when no motion has been detected during a five-minute
period, and thus, presumably, the room is unoccupied. This
signal can be used to turn off the lights in the room.
~ IG. 1 illustrates the electrical circuit diagram of
this motion detector 11. The detector 11 includes an elec-
trical circuit 12 having photosensitive means illustrated as
a photocell 13, which may be one of many types such as photo-
emissive, phototransistive or photoresistive. The output of
the photocell is connected to a detector 14, and the detector
in turn is connected to a timer 15. The timer 15 has an out-
put at 16 which is connected to load switch means 17, which
in turn is connected to load terminals 18, 18A of an elec-
trical load 19. In the embodiment of FIG. 1, this electrical
load 19 is illustrated as an electrical lamp which may illu-
minate a given area, including a ~ield of view 20. Illumina-
tion Erom this field of view, including the illumination
re1ected from the lamp 19, is directed by imaging means 21
to the photosensitive means 13. Image distortion means 2~
may be provided in the photocell 13 or, as shown, may be part
of the imaging means 13 by a separate element positioned
between the imaging means 21 and the photocell 13. The imag-
ing means in this embodiment is shown as a single lens to
pass radiation or illumination from the field of view to the
photocell 13.
The load switch means 17 includes, in this embodi-
ment, a set of timer contacts 26 and a solid state switch
27. An optically isolated Triac driver, for instance, may be
used as a timer contact means 26. The solid state switch may
be a reverse blocking triode thyristor or may be, as shown, a
bidirectional triode thyristor such as a Triac. This Triac
has the two main terminals thereof connected in series with
the load terminals 18 and in series with voltage supply ter-
minals 28 and 29. These supply terminals may be energized
with an alternating voltage supply, for example, 117 volts
~ . C . supply .
~2~ 3
A power supply 30 is provided to supply operating
voltages to the electrical circuit 12, and this includes a
breakdown diode such as a Zener diode 31, a diode rectifier
3~, and a filter capacitor 33. The Zener diode is connected
between the gate o~ the Triac 27 and a control terminal 34.
The normally open timer contacts 26 are connected between
this control terminal 34 and a main terminal 35 of the Triac
27. The other main terminal 36 of the Triac 27 is connected
to a common line 37 connecting one terminal 29 of the voltage
supply source and the power supply 30. A momentary contact
ON switch 39 is connected between the Triac terminal 35 and
the control terminal 34. A momentary contact OFF switch 40
is connected across the filter capacitor 33, which supplies
an operating voltage at a power supply output terminal 41.
This power supply output terminal 41 is connected to a line
42, supplying an operating voltage to the electrical circuit
12, which may include the photocell 13, detector 14, and
timer 15. The common or ground line 37 is also connected to
these same electrical components for a return circuit.
A manual or automatic switch 43 is connected in the
t.imer output line, and an indicating LED diode ~4 is con-
nected to the output of the detector 14.
Operation
The lamp 19 may be used to illuminate a field of
view 20 and to provide general illumination in a room (not
shown)O To establish this illumination~ the O~ switch 39 may
be momentaril~ pressed. This supplies voltage available at
the Triac terminal 35 through the Zener diode 31 to the gate
of this Triac, to fire the Triac. Prior to starting, there
is a voltage Vl as shown in FIG. ~, which is impressed
~2~7~63
across the terminals 35 and 36 of the Triac. At the time 45,
shown in FIG. 2, when the ON switch 39 is depressed, this
voltage Vl is impressed on the gate to fire the Triac.
When the Triac conducts, this illuminates the lamp 19, illu-
minating the field of view 20. The illumination from this
field of view is passed by the lens 21 through the image dis-
tortion means 24 to the photocell 13 which has an output
detected by detector 14 and energi.zing the timer 15. This
timer 15 is energized at a reset or restarting terminal, and
hence the timer 15 has an electrical output to close the
timer contacts 26. These are in parallel with the momentar-
ily closed ON switch terminals, and the closing of the timer
contacts 26 means that the ON switch may be released. The
timer contact 26 will remain closed, thus continuing to pro-
vide voltage to the gate of the Triac 27. The Zener diode 31
might have a breakdown voltage~ for example, of 10 volts, as
shown by the ~oltage V2 in F~ . This momentary spike of
voltage 46 is passed by the diode 32 to charge the capacitor
33. This supplies a unidirectional operating voltage to the
electrical circuit 12. This electrical circuit may have
minimal drain current, and hence the operating voltage may be
as shown by the dotted line 47, which will supply a satisfac-
tory operating voltage to power the electrical circuit 12.
~y this mea~s, the Triac is fired once each half-cycle to
keep the lamp 19 energ;zed, and the small spikes of voltage
4~ once each cycle provide the operating voltage for the
electrical circuit 12.
The image distortion means 24 may be a grating of
alternate transparent and opaque bands to cause the image of
the obiects which falls on the ~hotocell to be broken into a
series of light and dark bands. By this means, any motion of
ob~ects within the field of view 20 will cause a variation in
the illumination ~alling on the photocell, and hence a varia-
tio~ in the output of such photocell. Accordingly, the
11
photocell will have pulses of electrical output, and these
pulses are passed by the detector 14 to reset the timer 15
each time there is motion of objects within the field of
view. The timer may have a long time period, for example two
minutes, or preferably five minutes, because it has been
determined that human beings do not remain motionless for
such a long ~ime period. The load terminals 1~, 18A may
control such things as an electric soldering iron ox an
electric typewriter, for example, which may be de-energized
after the given time period of two to five minutes after a
person leaves the room, so that there is no more motion
detected within the field of view 20.
FI~ 3 illustrates a modi~ication o~ the invention,
wherein the imaging means 21A includes three lenses 52.
These three lenses supply different images from the field of
view 20 onto the photocell 13A. This photocell is one which
is provided with a sinuous photosensitive surface so as to
provide inherently the image distortion means within the
photocell 13A. Any motion detected in the field of view is
passed by the plural lenses 52 to provide nonuniform illumi-
nation o~ the photosensitive surface of the photocell 13A.
The nonuniEorm illumination provides nonuniform electrical
output, which is supplied to the differential inputs of an
amplifier 53 within the electri~al circuit 12~. These pulses
are amplified by the amplifier 53 and passed to a threshold
circuit 54, with the output thereof at 55 being passed to the
timer 15 of FIG. 1.
FIG. 4 illustrates another embodiment of the inven-
tion which includes an opaque screen 60 having a plurality of
pinholes 61. These plural pinholes may provide the imaging
means 21B to replace the imaging means 21 of FIG. 1 or 21A of
FIG. 3. Such pinholes do not provide as great a degree of
illumination on the photocell as the lenses of FIG~ 3; how-
ever, they provide a very good image because of the great
depth of field.
i3
FIG. 5 illustrates a housing 65 for the motion
detector 11. This housing ~5 may take many different forms
and, in the embodiment of FIG. 5, the housing consists of a
body 66 which can be fastened into the usual electrical out-
let wall box (not shown) with holding screws 67. The motion
detector 11, including the lens and the photosensitive means,
may be positioned in the rotatable cylinder 68, and this
cylinder has a blind or shield 69 to define the field of view
of the imaging means 21. The cylinder 68 may be rotated to
the desired field of view and then the cylinder may be
clamped by a clamping scrPw 70.
The electrical circuit 12 may be located in the com~
partment 72 which is attached to the body 66 and which will
fit within the electrical outlet box (not shown). The body
66 carries the push buttons for the momentary close ON switch
39 and OFF switch 40. The indicator LED diode 44 may be
provided in the body 6 and, optionally, the manual-automatic
switch 43 may be located on the body 66 in any convenient
location, such as on the lower surface thereof.
Another embodiment is shown in FIG. 6 for a desk-top
housing 78 or the like which has a cur~ed neck 79 at the end
of which is a blind or shield 80 to shield the imaging means
21~ In the base of the housing 78 there may be contained the
electrical circuit 12 and electrical outlets 81 into which a
lamp or appliance may be plugged for control of such lamp or
appliance. A flexible cord and plug 82 may be plugged into
the usual convenience outlet to provide power to the appli-
ance plugged into the outlet 81 and also to provide power to
the electrical circuit 12~ as set forth above. The OM and
OFF switches 39 and 40 may be provided in a convenient loca-
tion on the housing 78, and also the LED indicator diode 44
may be provided, for example, near the imagin~ means 21.
FIG. 7 is a schematic diagram of the complete
electrical circuit and many miniaturized components are
78~3
utilized so that the entire circuit llA of FIG. 7 may be pro-
vided on a printed circuit board, with the exception of some
peripheral components such as the indicator diode 44, the
manual/automatic switch 43, the photocell 13, and the ON/OFF
switches 39, 40. Many reference numerals on FIG. 7 are the
same as in FIG. 1 to show the correspondence between the two
circuits.
Power supply operating voltages are obtained across
the lines 42 and 37, and a voltage divider is provided there-
across including resistors 90, 91, 92, and 93. A resistor 94
and capacitor 95 are also connected across these power supply
lines, with the photocell 13 (in this embodiment a photore-
sistor) connected across the capacitor 95. A capacitQr 96 is
connected between the junction of resistor 94 and capacitor
95, and the junction between resistors 92 and 93. This same
junction is connected to the noninverting input of the ampli-
fier 53, which is one of a package of four such amplifiers in
a group, packaged for convenience, for example, in a DIP
package 89. The next op amp in the package is connected as
the threshold circuit 54, as in FIG~ 3. An op amp 97 is con-
nected as a part o the timer 15, which includes a resistor
98 and a capacitor 99. The last op amp 100 in the package is
connected as an amplif;er to drive the indicator LED diode 44
through a resistor 101 to the power supply terminal 41. A
resistor 102 connects this power supply terminal 41 to the
positive supply line 42.
The output o~ the timer amplifier 97 is connected
through a resistor 103 to the Triac driver 26, which includes
an opto-isolator device, namely, a light emitting diode 104
and a photodiac 105. This Triac driver 26 may be considered
an equivalent of the timer contacts 26 in FIG. 1, and is con-
nected between terminals 18 and 34.
The output of the timer amplifier 97 is also con-
nected through a diode 108 to a terminal 109, which is
~207~3~3
14
connected to the inverting input of amplifier 53. Terminal
109 is connected through a resistor 110 and a capacitor 111
to the negative power supply line 37. ~ resistor 112 and
capacitor 113 are connected in parallel from the output of
amplifier 53 to the terminal 109. A capacitor 11~ is con-
nected from the output of amplifier 53 to the negative supply
line 37~ A diode 115 is connected from the junction of
resistor 110 and capacitor 111 to a terminal 116, which is
connected to the positive supply line 42. A transistor llB,
with base left open, is connected between the terminal 116
and the negative supply line 37.
The power supply 30 is connected, as in FIG. 1, to
supply a positive DC operating potential at terminal 41. The
OFF switch 40 is connected between terminals 34 and 41, and
the ON switch 39 is connected between terminals 18 and 34.
The main terminals 35 and 36 of the Triac 27 are connected
across terminals 18 and 2g. A small series inductance 120 is
connected between terminals 18 and 28, and a parallel capaci-
tor 121 is connected across terminals 28 and 29. This induc-
tance and capacitance is for surge current protection to the
Triac 27. The gate of the Triac 27 is connected through a
resistor 122, and the Zener diode 31 to the terminal 34~
Terminals 12~ and 125 are connected by an optional jumper 126
in order to in~erconnect terminal 29 with a negative supply
line 37, The manual-automatic switch 43 has ~he wiper of the
switch connected to the inverting input of the timer ampli-
fier 97, and the automatic terminal 128 connected to a junc-
tion 129 between resistors 90 and 91 in the voltage divider.
The manual terminal 13Q of the switch 43 is connected to the
positive supply line 42. ~ junction 132 between resistors 91
and 92 on the voltage divider is connected to the noninvert-
ing input of amplifiers 54 and 10G. The inverting inputs of
these amplifiers 54 and 100 are connected to a line 133,
which is connected through a resistor 134 to the terminal
863
116. The diode 32 may be connected to conduct from terminal
34 to terminal 41 or, alternatively, may be connected to con-
duct between a terminal 135 and the terminal 41.
Operation
FIG. 7 illustrates one practical circuit which will
put into practice the objects of the invention. The circuit
11~ of FIG. 7 may be connected in either the wall switch
assembly of FIG. 5 or the desk-top assembly of FIG. 6. FIG.
8 illustrates how this circuit llA might be connected in the
wall switch assembly of FIG. 5 to control the lamp load 19
from the voltage source connected at terminals 28 and 29. In
this circuit, ~umper 126 connects terminals 124 and 125. In
this connection, the circuit llA controls the room illumina-
tion and a major portion of the room, or a portion selected
by rotating cylinder ~8, would be the field of view 20. When
a person enters the room, he depresses the ON switch 39 for a
short period of time, for example one-hal second. In the
circuit of FI~. 7, it will be noted that this interconnects
terminals 18 and 34 to energize the gate of the Triac 27 and
cause it to fire r thus establishing a closed circuit between
terminals 28 and 29. This will illuminate the lamp 19. The
small spikes of voltage 46 shown in FIG. 2 are those estab-
lished by the Zener diode 31, and these are passed to the
power supply 30 to establish a d.c~ operating voltage at the
terminal 41 and through resistor 102 on the positive d.c.
conductor 42. The capacitor 33 may be large for a large
filtering capacity, so that an essentially d.c. voltage is
applied to the conductor 42~ The transistor 118, with an
open base connection, is connected to operate in the Zener
mode for a regulating fun~tion of maintaining a substantially
63
16
constant voltage on the conductor 42, e.g., 7 volts. This
voltage is applied to the voltage divider 91, 92~ 93, to
establish the operating conditions of the four op amps in the
package 890 The resistors 90 and 91 may be of relatively
large value compared to the resistance value of resistors ~2
and 93. Thust the potential at terminal 136 may be low, for
example, only about 2 volts. The photocell 13 in this embod-
iment is a photoresistor having a high impedance when dark
and a considerably lower impedance when light strikes the
photocell. Initial application of light on this photocell ~s
passed as a pulse of li~h~ through the capacitor 96 to the
amplifier 53. The feedback resistor 11~ may be of a very
large resistance value for a high gain of this amplifier.
The light pulse is therefore amplified as a voltage aOc.
pulse on the output of the amplifier 53. The amplifier 54 is
used as a threshold detector and the potential of terminal
132 might be a low voltage, for example, 2 to 3 volts. The
capacitor 99 may be of large value and resistor 98 may be of
large value for establishing an RC time constant of two to
fi~e minutes.
Upon closing the ~N switch 39 and conduction of
Triac 27, the capacitor 9~ immediately starts to charge at
terminal 137, slowly, through resistor 98 from terminal 116.
This initially is a lower positive voltage on the noninvert-
ing input of op amp 97 than on the inverting input from ter-
minal 1~9 of the voltage divider. Consequently, op amp 97
has a negative output on line 55 to turn on the LED 104 and
turn on the photodiac 105 r which keeps the Triac 27 turned
on. All this occurs within a few cycles of the 60 Hertz
applied power and then the person entering the room may
remove his finger from the momentary close ON switch 39 and
the room lights will stay energized.
The motion being detected within the room will cause
variations of impedance on the photoresistor 13. The normal
~Z~7t~3
17
variations on this resistor caused by changes of illumina-
tion, for example, the 120 Hertz variations Erom fluorescent
lamps on a 60 Hertz power supply, will be filtered out by the
capacitor 95, so they will not be passed by capacitor 96.
However, motion changes within the room through the imaging
means 21 and image distortion means ~4 will cause voltage
changes to be passed by ~he capacitor 96 to the amplifier
53O These motion changes are therefore trans~ormed into an
alternating voltage wave on the output of this amplifier 53.
Since the feedback resistor 112 is a very large resistance,
for example, 10 megohms, the amplifier 53 has a very high
gain. Consequently, the alternating voltage output of the
amplifier 53 will be applied to the threshold ~etector 54 on
the inverting input thereof, and these alternating voltage
waves will have portions exceeding the threshold established
by the potentia~ at voltage divider terminal 132.
When such threshold is exceeded, the output transis-
tor of the threshold detector op amp 54 will be saturated,
and hence have an impedance of only 2 or 3 ohms r which will
immediately discharge the capacitor 99. This is a resetting
or restarting o the timer 15 by the discharge of the capaci-
tor 99~ B~ this means, the noninverting input of the timer
op amp 97 will normally, with room illumination and movement
within the room, be at a positive potential less than that
established on the inverting input from the voltage divider
terminal 129. This potential might be 5 to 6 volts posi-
tive. This positive voltage on the inverting input estab-
lishes a large negative voltage on the output of op amp 97 to
maintain the ~ED 104 illuminated t the photodiac 105 conduct-
ing t and ~riac 27 conducting. As each movement within the
room is d~tected~ this again discharges the capacitor g9, or
i~ effect restarts or resets the timer 15. ThuS, as long as
the room is occupied, the slight movements of the occupants
or movements made by objects moved by the occupants will be
7863
18
detected by the circuit llA to keep capacïtor 9g discharged
and the Triac 27 energized for continued room illumination.
When the occupant leaves the room and does not turn
off the lights by means of the OFF switch 40, then no further
motion will be detected within the room. This discontinuance
of motion will be detected by the circuit llA because there
will no longer be any a.c. variations to amplifier 53 and no
longer any discharging of capacitor 99 through the threshold
detector 54O This means that throu~h the large value resis-
tance 98, the capacitor 99 will slowly charge. When the
potential across this capacitor 99 reaches the 5 or 6-volt
value of terminal 129 of the voltage divider, then the timer
op amp 97 will time out by switching from a negative output
to a positive output. This turns off the LED 104 and turns
off the photodiac 105 and Triac 27.
The initial turnoff of the room lights is a change
of illumination which will be detected by the circuit llA
because th~ large capacitor 33 is still charged as a part of
the power supply. The lights might turn on again except for
the circuit established by diodes 108 and 115. Initial posi-
tive output of the timer op amp 97 on the output line 55, for
turn-off, is passed by diode 108 and this voltage at the d.c.
supply ~oltage of seven volts, for example, will drive the
amplifier 53 heavily negative at its output on line 133.
This helps to discharge the capacitor 33 through resistors
13~ and 1~2. The positive voltage supplied through diode 108
also starts to charge capacitor 111 and so diode 115 will
discharge this capacitor 111 through transistor 118. This
diode 115 also has the function of permitting the circuit to
be turned on quickly by the manual switch 3g, once it has
been turned off~ It establishes the discharge of capacitor
99, so it is below its threshold value, and hence the circuit
may be turned on quickly.
7f3~3
19
FIG. 9 shows how the circuit llA of FIG. 7 may be
used in the desk-top switch assembly such as that shown in
FIG. 6. The cord and plug assembly 82 is connected between
terminal 23 and one terminal of the electrical outlet 31.
The other terminal of this outlet 81 is connected to terminal
18. An external eapacitor 139 may be connected between this
terminal 18 and terminal 135, with the diode 32 connected
between this terminal 135 and terminal 41.
The capaeitor 139 may have a 120-volt rating for a
117-volt a.c. input, altho~gh if it is a 230-volt a.c. input
this capacitor 139 is rated accordingly at 25~ volts, for
example. ThiS capacitor supplies energy to the circuit llA
in parallel with the outlet 81l and does so through the diode
32.
This desk-top assembly of FIG. 6 may be used to con-
trol a desk lamp, for example, or some appliance such as an
electric typewriter, with such lamp or appliance plugged into
the outlet 81. Assume that the desk-top unit of FIG. 6 is
not controlling any illumination within the room, i.e., not
controlling a desk~lamp, but is controlling only an electric
typewriter. ~lso assume that there is sufficient illumina-
tion in the room for the oecupants. Then when the typewriter
is turned on, this establishes an electrical circuit through
the outlet 81 so that a potential is applied on terminal 18,
and from this terminal, through capacitor 139 and diode 32,
the circuit llA is energized so that thi~ circuit will be
responsive to movement within the room and will also be
responsive to discontinuance of this movementl so that two to
five minute~ later, the Triac ~7 will cease conduction and
turn off the electric typewriter.
It will be noted that the indicating LED diode 44
will be flashing each time motion has been detected to
provide an indication of proper operation of the circuit 11.
7~3
The manual-automatic switch 130 is an option which
may be provided if desired. The circuit has been described
with this switch 43 in the automatic position, but when the
switch is changed to the manual position, the circuit is
operable manually merely by pressing the ON or OFF switches
39 or 40, respectively.
The motion detector 11 has contained therein the
timer 15 so that an output signal is produced when no motion
has been detected for a given period of time after the last
detected motion. This signal is used to turn off the lights
in a room, for example, or to turn off som~ electrical appli-
ance. Each time motion is detected, the timer 15 is restart-
ed or reset and begins to count time again from time zero.
The output signal from the timer will occur only if the
intervals between motions of the objects within the field of
view are greater than the preset time interval. This may be
two to five minutes, for e~ample. Since this motion detector
11 utilizes only "yes" or "no" type information corresponding
to the presence or discontinuance of motion, this detector
can utilize the simple and inexpensive motion detector shown
in FIGS. 1 and 7. Motion detectors known from the prior art
can detect motion as well as direction, speed, etc., and
therefore often are relatively complicate~. The present
invention, there~ore, utilizes a circuit which is relatively
simple and reliable, yet inexpensive and requiring no tuning,
and one which ~an be made relatively sensitive to detect
small amounts of motion within the field of view. Addition-
ally, the shields or blinds Ç9 and 80 can select the desired
~ield of view and, at the same time, can shield the photosen-
sitive means 13 from ambient light, such as light from a
window or overhead room illumination lights. This means that
the photosensitive means 13 is responsive primarily to
re~lected light from objects within the field of view 20.
~IU7~
21
The image distortion means 24, 21~ and 13A, or 21B
and 13B is one which breaks the imaye into several different
areas which affect the photosensitive means 13. The imaging
means can include one or several lenses or one or several
pinholes, so that any objects or subjects moving within the
field of view establish light modulations on the surEace o~
the photosensitive means 13 and, consequently, a pulse is
produced by the detector 14.
The power supply 30 establishes an operating voltage
for the operation of the electrical circuit or any part
thereof without the necessity for supplying a separate pair
of conductors to this power supply. This power supp~y 30
obtains its energy from the motion detector circuit 11 it-
self, so that only connections of the detector circuit ~o the
volta~e supply terminals 28 and to the load terminals 18 are
required. Accordingly, the motion detector of FIGS. 1, 3 and
7 is powered while the load lg is powered and the motion
detector circuit 11 does not consume any energy during the
OFF condition. The motion detector 11 is turned on manually
by the ON switch 39, and thereby the load 19 is energized
from the voltage supply terminals 28. While people are in
the vicinity of the switch and these people are moving, their
every motion produces the output signals from the motion de-
tector 14, which returns the timer 15 to the starting posi-
tion. Once the person has left the room or the field o~ view
~0, then when the timer times out, the load 19 is de-
energized and also the power supply 30 is de-energized so it
does not consume any power. FIG. 5 shows how the motion
detector may be built into the ordinary wall switch and FIG.
6 illustrates how the mo~ion detector may be housed in a
desk-top type of housing to monitor the motion of a person at
the desk or at a workbench. Also, the motion detector 11 may
be built directly into the electrical appliance, such as the
3~Z~786~
22
electric typewriter, electric desk lamp, or electric solder-
ing iron used at a workbench, and thus can become a part of
these electrical appllances, thus making them not only more
energy-efficient, but also safer in terms of fire, etc.
The circuit of the motion detector of ~IG. 1 may be
constructed in several ways, with FIG. 7 illustrating one
practical circuit which has been constructed and satisfactor-
ily operated. As an example, the values of the circuit com-
ponents in FIG. 7 may be as follows:
Ref._No. Component Value ~2~
13 photoresistor Cl 700
26 opto-coupler MOC 3020
27 Triac lR 106 Bl
31 Zener diode lN 714 A
32 diode lN 4001
89 quad op amp 2M 33g
108 diode lN 914
115 diode lN 914
118 transistor 2N 4916
120 inductance l00~UH
12Q78G3
23
Ref. No. Component Value Type
33 filter capacitor50 mfd 15V
capacitor .2 mfd lOV
96 capacitor 1.0 mfd
99 capacitor 50 mfd aluminum
111 capacitor 10 mfd
113 capacitor .01 mfd
114 capacitor .1 mfd
121 capacitor .1 mfd 200V
139 capacitor .1 mfd 120V or 250V
resistor 1 megohm
91 resistor 1.5 megohm
92 resistor 220 K ohm
93 resistor 550 K ohm
94 resistor 68 K ohm
98 resistor 4.7 megohm
101 resistor 3.3 K ohm
102 resistor 1.2 K ohm
103 resistor 3.3 K ohm
110 resistor 10 K ohm
112 resistor 10 megohm
122 resistor 100 ohms
134 resistor 47 K ohm
The present disclosure includes that contained in
the appended claims, as well as that of the foregoing de-
scription. Although this invention has been described in its
preerred form with a certain degree of particularity, it is
understood that the present disclosure of the preferred form
lZ~ 3
24
has been made only by way of example and that numerous
changes in the details of the circuit and the combination and
arrangement of circuit elements may be resorted to without
departing from the spirit and scope of the invention as
hereinafter claimed.
