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Team Pishro-Nik and Ni
Chris Comack - Simon Tang - Joseph Tochka - Madison Wang
Car-to-Car Communication
for Accident Avoidance
March 5, 2009
Professor Pishro-NikAdvisor, Assistant Professor,
ECE
Professor NiAdvisor, Assistant Professor,
CEE
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Background Automobile accidents are both dangerous and costly
• Over 42,000 fatalities in the United States every year. • More than 2.9 Million injuries from 6.4 Million car accidents
annually.• Combined cost of 230+ Billion dollars per year. • Responsible for 5% of preventable deaths each year (JAMA).
Goal: To provide a system to reduce these rates by warning drivers before a collision happens. How?• Use GPS to track position and vehicle’s OBD-II port to monitor
speed and acceleration of vehicles.• Communicate this information among cars on the road via
Dedicated Short Range Communication in the 5.9GHz spectrum.Source: Mokdad AH, Marks JS, et al. (March 2004). "Actual causes of death in the United States, 2000". JAMA 291 (10): 1238–45.
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Scenario
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Scenario
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Review of Situations
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Proposed Solution
Use of Car to Car Communication
• Cars 2 & 3 emit audio warning indicating Car 1 is decelerating rapidly.
• The cars operators now have more time to respond to this dangerous situation, decreasing the risk of collision.
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Collision Detection Algorithm
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Design & Requirements
System must be scalable Track car’s location with GPS receiver Use OBD-II (on-board diagnostic connection) to
monitor speed, acceleration, and other information from car’s computer• Standard on all cars made after 1996 –
includes 150 million+ cars on the road in the U.S. today.
Communicate between vehicles using DSRC (Dedicated Short Range Communication) Transceiver
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Block Level Diagram
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GPS – Progress
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GPS – Problem
No GPS Coordinate in Response Message
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GPS – Progress
Process Response Correctly if there are GPS Coordinates
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GPS Statistics
Measure Latitude/Longitude in One Location Refreshes Coordinates
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Inputs & Outputs
Inputs:SPST Power Switch, two momentary push-buttons.
Outputs: Green LED indicator, red LED warning light, Piezoelectric element for audible warning.
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Data Collection
GPS coordinates updated at rate of 1 Hz. Time-stamp acquired from GPS at same rate. Heading, or compass direction, calculated from
comparing GPS location to previous coordinates. Speed information from Engine Control Unit
polled at approximately 10 Hz. Acceleration calculated from current and
previous velocity values. Control signal to monitor transceiver buffer;
above five data points received from other units at max. frequency possible.
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Data Transmission
Total processing time is minimized by performing heading and acceleration calculations before transmitting.
Minimal packet size allows frequent transmission of single packet containing all pertinent information.
Data transmitted after each update to prevent stale data. “Dead reckoning” also implemented to fill in the blanks between each GPS update.
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Software Flowchart
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Transceiver updates
Goals from last time • Confirm Range (at least 150 m)
• Tested at 160 m• Implement/confirm receiving functionality
To do• Integrate with GPS, OBD-II• Receive/send from multiple sources
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Ethernet Packet Structure
Header• 33 bytes• SRC/DST MAC addresses• SRC/DST IP addresses• Length
Other data and payload• Transceiver info
• Channel/power to send, etc.• Payload, padding, checksum
• Payload will include position, speed, timestamp, acceleration, and heading
• ~13 bytes
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PCB Progress
Currently only the layout for transceiver portion is done
Things to come• GPS interface (serial port)• OBD-II interface layout• Inputs & Outputs• Ship out design for manufacturing
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Price of individual PCB
NumberManufacturer Part Number Supplier Package Description
Quantity Price Total Total PCB Price
1 LT1086 Digikey TO-220 3.3V fixed regulator 1 4 4 89.231
2 LM340 Digikey TO-220 5V fixed regulator 1 1.74 1.74
3 ATMEGA128 Digikey TQFP-64 Microcontroller 1 15 15
4 ENC28J60-H Sparkfun 10-dipEthernet Controller header 1 35 35
5 Jtag connector 0
6 ELM327Elm Electronics 28-SOIC
OBD to RS232 interpreter 1 25.5 25.5
7 TCA1A226M8R Digikey 1206 22 uF cap 2 0.33 0.66
8 Magellan A12 Magellan GPS 0 100 0
9 Denso Transceiver Denso Transceiver 0 0
10 ECJ-2VB1E104K Digikey 805 0.1 uF cap 10 0.1 1
11 FMMT597TA Digikey sot-23 PNP BJT 3 0.54 1.62
12 MMBTA06-7 Digikey sot-23 NPN BJT 6 0.49 2.94
13 ERJ-6GEYJ472V Digikey 805 4.7k resistor 6 0.077 0.462
14 ERJ-6GEYJ473V Digikey 805 47k resistor 2 0.077 0.154
15 ERJ-6GEYJ471V Digikey 805 470 resistor 4 0.077 0.308
16 ERJ-6GEYJ103V Digikey 805 10k resistor 6 0.077 0.462
17 ERJ-6GEYJ223V Digikey 805 22k resistor 5 0.077 0.385
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PCB Progress