Emergency Vehicle Detection System

Nikhil VidyasagarAditya Jain

Michael Bianchi

Objective

• This project involved the construction of an emergency vehicle (EMV) detection system that can be used to warn hearing-impaired drivers of approaching emergency vehicles.

• In addition to aiding the hearing impaired, the device will also help preoccupied drivers recognize the presence of emergency vehicles when listening to music or when the windows are closed.

Background• The Optical Emitter is used by emergency

vehicles to initiate pre-emptive traffic sequences at intersections. These pre-emptive sequences are used to clear the intersection and give the emergency vehicle priority.

• Sirens emit sound in a defined frequency range and follow peculiar, yet recognizable, auditory patterns. These patterns include: Wail, Yelp, Piercer, and Hi-Lo– Hi-Lo has two frequency components at ~1100 Hz

(High) and ~1000 Hz (Low)

Introduction

• System will warn drivers of approaching emergency vehicles

• Will take advantage of both Siren and the Optical Emitter in its detection scheme

• Will be using LabVIEW to implement detection algorithm (proof-of-concept)

Benefits

• Reduce emergency vehicle related accidents

• Alert hearing impaired drivers of an approaching emergency vehicle

• Alert distracted/preoccupied drivers of any approaching emergency vehicles

Features

• Autonomous • Low Power Consumption • Accurate • Reliable • Affordable Price

High Level Block Diagram

Hardware

IR Receiver

• The infrared sensor will be used to detect the IR signal of approaching emergency vehicles.

• The implementation circuit is included in the IR module. This circuit will amplify the incoming infrared signal and also provide noise rejection.

Microphone

The microphone will monitor the audio space in the vicinity of the passenger’s vehicle.

Pre-Amplifier

• This circuit amplifies the microphone signal to about 23x the input from the condenser microphone.

IR Emitter

The initial emitter used for testing was built using a large IR Photodiode array and a clocking circuit set to 14 Hz.

TOMAR Optical Emitter

The TOMAR STROBECOMII EMIT3B was used for final testing. It emits an optical signal at 14.035 Hz + or – 0.5 Hz.

Hardware Components

Software

Siren Detection Flow Chart

Siren Detection

Placement of Microphones

• Microphones would be placed on side-view mirrors (some weather-proofing might be needed)

• Placement in side-view mirrors would provide access to wiring that would be able to display presence of siren in the vehicle cabin

Siren Detection Considerations: Echoes

• Echoes are just time-shifted, attenuated versions of the original signal

• The frequency content of the echo does not change, thus any echoes will actually help in the detection of a siren

Siren Detection Considerations: Doppler Effect

•V is the velocity of waves in the medium (sound travels at 345 m/s in air)•Car/Ambulance moving at 56 mph = 25 m/s•Relative to speed of sound in air, there will not be a huge shift in frequency•Accounted for in detection algorithm by having ranges for frequency detected

Testing the Siren Detection

• Must not output any false positives• Must be able to detect siren in the

presence of other noise • Three main tests

– Ideal Siren Signal (directly fed into LabVIEW)

– Random Noisy Signal (music, etc.)– Siren Signal with Noise (must detect)

Ideal Siren Frequency Content

Noisy Signal Frequency Content

Siren with Noisy Signal Frequency Content

IR Detection Flow Chart

Optical Emitter Detection

Placement of IR receiver

• Possible placement would be on roof of vehicle

• Multiple IR receivers would be placed to make sure line-of-sight is achieved

Testing the IR Detection

• Must detect IR signal from the transmitter (14 Hz signal)

• Must not detect IR signal outside of 14 Hz range

• Two main tests– Must detect when IR transmitter is used– Must not detect when other IR

transmitter device (remote control, etc.) is used

Actual IR Signal

Remote Control IR Signal

Future Extensions

• Be able to detect all types of sirens that are emitted

• Use the Doppler Effect to determine which direction the emergency vehicle is coming from– Frequency is upshifted if source is

moving towards receiver– Frequency is downshifted if source if

moving away from receiver

Commercial Extensions

• Final product (with LabVIEW algorithm on hardware) can be marketed as an addition to most GPS systems– Would be most likely a firmware update

for GPS systems with some sort of sensor pack

– Show location of emergency vehicle on the GPS screen

Ethics

• The overall goal of this project is to improve the lives of individuals who use it. Advanced notice of emergency vehicle presence will hopefully help to reduce the number of accidents involving emergency vehicles en route. However, certain aspects of this project may be abused.

• The device may be used to avoid law enforcement personnel or receive advanced notice of their presence.

• Also, the infrared transmitter that was used to test the IR detection capabilities of this system may be used to illegally alter traffic flow patterns or otherwise compromise pre-emptive traffic control systems. Effort was made to ensure that the transmitter was not used for any purpose outside of testing the EMV detection system.

• In short, the benefits of this device outweigh the possible risks of abuse.

Thanks!

• Dr. C. D. Schmitz• Professor Steven J. Franke• Professor Douglas Jones • Professor Gary Swenson• TA: Mary DeRoo• ECE 445 Support Staff• ECE Parts Shop

Questions???