EMERGENCY VEHICLE ALERT SYSTEM

ECE 495C Digital Systems Senior Design Project ProposalTeam #3 Spring 2008

January 09, 2008

Overview

An emergency vehicle alert system would provide indication to motorists of the presence of an emergency vehicle such as police, fire trucks, and ambulances in their vicinity. The system is activated when the sirens of the emergency vehicle are turned on. The emergency vehicle is equipped with a GPS receiver to mark its location, and an RF transmitter to broadcast the vehicle type (fire, police, medical, other) and its present GPS location to surrounding vehicles. Individual motorists are equipped with a GPS receiver of their own, and an RF receiver. The RF receiver will detect when an emergency vehicle broadcast is being made, and thus an emergency vehicle is in the area. An RF front end will demodulate the transmitted data. A local microcontroller will calculate the distance, relative location, and direction of travel of the emergency vehicle from their present vehicle location by comparing the transmitted and local GPS data. An LCD screen and speakers will alert the motorist of an emergency vehicle’s presence.

System Block Diagram I

Emergency Vehicle System (Transmitter)

GPS Receiv

er

Microcontroller

FSK/PSK/ASK RF

Transmitter

Keypad ID

LCD Vehicle / System Info

Display

Power Supply

Activation Switch

System Block Diagram II

Motorist Vehicle System (Receiver)

GPS Receiv

er

Microcontroller

FSK/PSK/ASK RF Receiver

Alert Speakers

LCD Warning Display

Power Supply

Power Switch

Additional Possibilities / Features Create secure open-channel communications broadcast. Such

an application may allow police to key in the license plate number of an offender, encrypt and broadcast the plate number and the offender’s unit would signal that they have been flagged to be pulled over. (FUN!)

Only allow use of transmitter by authorized individuals. May need to enter identification number to unlock with keypad or other means such as programmed RFID tag, fingerprint scanner, etc.

Programmable transmission range. Interface with commercial GPS receiver map software to

somehow overlay location of emergency vehicle on display screen.

Technical Challenge – How to handle multiple transmissions / multiple emergency vehicles.

Technical Challenges & Risks Determine how to handle multiple emergency vehicle alert

transmissions. Require multiple frequency bands? FCC regulations for mid-range power (i.e. ~0.5 mile radius)

RF broadcasting. Determination of appropriate transmission modulation

scheme. GPS receiver reliability Transmission interference Requires two microcontrollers

Project Positives

Compact and efficient mechanical design very possible. Tractable, interesting, but sufficiently difficult. GPS receivers have well-defined NMEA RS-232 serial output code

standards for microcontroller interfacing. Short range (~500 ft) RF transcievers readily available and

inexpensive for possible senior design course prototyping purposes.

Numerous possibilities for user interfaces. May use inexpensive and simple keypads and LCD screens that have been well documented and used in the past or may venture into larger displays.

Easy power supply design! Tap into vehicle 12 VDC power and use voltage regulator to step down to 5 V for all components. No need for battery backup circuit or AC to DC conversion from wall outlet.

Good amount of analog and digital work with reasonable number of interfacing devices.