Note: Descriptions are shown in the official language in which they were submitted.
CA 02591099 2007-06-08
EMERGENCY VEHICLE ALERT SYSTEM
BACKGROUND OF THE INVENTION
[0001] This invention relates to apparatus for detection of selected sound
frequency signals emitted by sirens of emergency vehicles or warning signals
from vehicles such as trains. The new apparatus may detect a selected sound
frequency signal spectrum emitted by various siren or warning sound sources
from at least two distinct distances from a sensor to provide a user with a
waming of the presence of an emergency vehicle and the relative distance of
the
emergency vehicle.
[00021 Various types of emergency vehicle siren detection systems may
be currently known; however, these systems tend to be complicated, elaborate
apparatus. The system may involve digital signal processing and programming
as part of the detection and differentiation process for detecting sirens of
emergency vehicles. There may be a need for a simple, easy to apply siren or
warning signal detection system.
SUMMARY OF THE INVENTION
[0003] The present invention is directed to apparatus for detection of
selected sound frequency signals emitted by waming devices of vehicles. A
sensor may sense a selected sound frequency signal spectrum and may be in
communication with multiple operational amplifiers. The operational amplifiers
may be biased to detect a warning device sound source within 50 feet and
within
1,500 feet of the sensor. The detection of a waming device sound source may
be communicated to a waming indicator to activate the warning indicator.
[0004] These and other features, aspects and advantages of the present
invention will become better understood with reference to the following
drawings,
description and claims.
1
CA 02591099 2007-06-08
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] Figure 1 illustrates a schematic of the emergency vehicie alert
system according to an embodiment of the invention;
Figure 2 illustrates a traffic roadway and vehicles according to an
embodiment of the invention.
DETAILED DESCRIPTION
10006] The following detailed description represents the best currently
contemplated modes for carrying out the invention. The description is not to
be
taken in a limiting sense, but is made merely for the purpose of illustrating
the
general principles of the invention.
[0007] Referring to Figures 1 and 2, an emergency vehicle alert system 40
may have four audio frequency selection or detection circuits to detect
selected
sound frequency spectrum signals that may be transmitted by emergency
vehicles 50, such as, ambulances, police cars, fire engines and the like, that
may
use roadways for travel. Two of the detection circuits with operational
amplifiers
20, 24 may be biased to detect the presence of low frequency spectrum sound
attributabie to warning devices or sirens used by emergency vehicles 50. Two
detection circuits with operational amplifiers 22, 26 may be biased to detect
the
presence of high frequency spectrum sound attributabie to sirens of emergency
vehicles 50.
[0008] The sensing element for the audio sound waves of a warning
device or sirens may be a microphone 30 that may be in communication with the
operational amplifiers 20, 22, 24, 26 to transmit the desired signal level for
the
received audio sound frequencies that are to be detected. A prototype circuit
using operational amplifiers LM324M was fabricated and tested. Other
operational amplifier type may also be used with appropriate selection of
other
circuit components.
2
CA 02591099 2007-06-08
[0009] The operational amplifiers 20, 22, 24, 26 may also be biased to
detect a received audio sound frequency at 1,500 feet or less and at 50 feet
or
less. In Figure 1, the Interconnection of components and the operational
amplifiers 20, 22, 24, 26 may be selected for biasing amplifier 20 to detect
low
frequency spectrum sound attributable to a siren source that may be 50 feet or
less distance from the sensor 30. Operational amplifier 24 may be biased to
detect low frequency spectrum sound attributable to a siren source that may be
1,500 feet or less distance from sensor 30. This combination may allow early
waming of an emergency vehicle 50 emitted low frequency siren sound waves at
1,500 feet distance and a heightened alert warning when the emergency vehicle
50 may be within 50 feet of the sensor 30. Such a staged waming system that
may provide waming of the presence and relative distance may allow a vehicle
52 driver time to react to avoid any danger associated with the emergency
vehicle 50 movement.
[0010] Similarly, the operational amplifier 22 may detect high frequency
audio sound within 50 feet and the operational amplifier 26 may detect high
frequency audio sound within 1,500 feet. A warning indicator 32 that may be
connected to the operational amplifiers 20, 22, 24, 26 to have a repetitive
low
speed flashing illumination when a siren is detected within 1,500 feet of
sensor
30 and to have a repetitive high speed flashing illumination when a siren is
detected within 50 feet of sensor 30. A variable rate warning indicator 32
compatible with the circuitry of Figure 1 may be selected to produce the
desired
effect.
[0011] The emergency vehicle alert system 40 may be connected to the
vehicle 52 electrical power system and may be mounted adjacent the steering
column on the dash board to facilitate waming of the vehicle 52 driver. The
emergency vehicle alert system 40 may also have a back up power source in the
event the vehicle 52 power source may be interrupted. The sensor 30 may be
mounted external to the vehicle 52 interior to improve sensor detection of
siren
sound waves.
3
CA 02591099 2007-06-08
[00121 The system 40 has been described relative to emergency vehicle
50 sound detection as for example a sound emitted by a siren; however, other
waming sound signals such as a train whistle may also be detected. By
selection of appropriate component values in the illustrated circuit for bias
and
operation of the operational amplifiers 20, 22, 24, 26 a train whistle or
other
vehicle warning sound may be detected. This additionai electronic circuitry
may
be housed in a common receiver unit with a siren alert system. A separate
waming indicator 32 may be located on the receiver unit to identify the type
of
sound detected.
[0013] While the invention has been particularly shown and described with
respect to the illustrated embodiments thereof, it wifi be understood by those
skilled in the art that the foregoing and other changes in form and details
may be
made therein without departing from the spirit and scope of the invention.
4
