Transcript Comprehensive Design Review (CDR) Presentation

March 5, 2009
Car-to-Car Communication
for Accident Avoidance
Team Pishro-Nik and Ni
Chris Comack - Simon Tang - Joseph Tochka - Madison Wang
Professor Pishro-Nik
Advisor, Assistant Professor, ECE
Electrical and Computer Engineering
Professor Ni
Advisor, Assistant Professor, CEE
1
Background
 Automobile accidents are both dangerous and costly
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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.
Electrical and Computer Engineering
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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.
Electrical and Computer Engineering
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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
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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
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GPS interface (serial port)
OBD-II interface layout
Inputs & Outputs
Ship out design for manufacturing
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Price of individual PCB
Number
Manufacturer Part
Number
Quantit
y
Price
Supplier
Package
Description
Total
1 LT1086
Digikey
TO-220
3.3V fixed regulator
1
4
4
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-dip
Ethernet Controller
header
1
35
35
5 Jtag connector
Total PCB Price
89.231
0
6 ELM327
Elm
Electronics
7 TCA1A226M8R
Digikey
8 Magellan A12
9 Denso Transceiver
OBD to RS232
interpreter
28-SOIC
1
25.5
25.5
1206 22 uF cap
2
0.33
0.66
Magellan
GPS
0
100
0
Denso
Transceiver
0
805 0.1 uF cap
0
10 ECJ-2VB1E104K
Digikey
11 FMMT597TA
Digikey
sot-23
12 MMBTA06-7
Digikey
sot-23
13 ERJ-6GEYJ472V
Digikey
805 4.7k resistor
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
Electrical and Computer Engineering
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0.1
1
PNP BJT
3
0.54
1.62
NPN BJT
6
0.49
2.94
6 0.077
0.462
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PCB Progress
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