This document describes the design of a CAN-based accident avoidance system for vehicles. It uses ultrasonic sensors to detect objects and the LPC2129 microcontroller to process sensor readings and transmit data via CAN protocol. If an obstacle is detected, the system will trigger alarms and automatically apply emergency braking to prevent accidents. The system is intended to increase road safety by warning distracted drivers or taking evasive action if drivers cannot respond in time to potential collisions.

2. Content:
1. Introduction
2. Literature survey
3. Need and objective
4. Block diagram of system
5. Ultrasonic sensor
6. Lpc2129
7. Controller area network protocol
8. System based some pictorial view
9. Conclusion
10. Application

3. INTRODUCTION
 It is an embedded system based application. The main design aspect
of CAN Based accident avoidance system project is to avoid the
accidents by using CAN protocol. This Project describes a design of
effective accident avoidance system that detects an automotive / vehicle /
car condition in traveling with the help of ultrasonic sensors and this
signal can be used to switch off the apply emergency hand brake or disc
brake with the help of which accident can be avoided.

4. LITERATURE REVIEW
ABS
ADVANCE
SYSTEMS
FOUND IN
CARS
EBD
PARKING
SENSORS
CRUISE
CONTROL

5. NEED
In Present scenario maximum number of deaths is due to
accidents main reason for accidents are due to negligence of
drivers. In order to solve this problem we use can based
accident avoidance system which will collect traffic
information surrounding moving car and inform to driver in the
form of alarm.

6. LPC 2129 POWER
SUPPLY
CAN
TRANSMITTER
ULTRASONIC
SENSOR
POWER LPC2129
SUPPLY
LCD BUZZER
CAN RECEIVER
TRANSMITTER SECTION
RECEIVER SECTION

7. CAN BASED ACCIDENT AVOIDANCE SYSTEM

8. ULTRASONIC SENSORS
An ultrasonic sensor transmit ultrasonic waves into
the air and detects reflected waves from an object.
There are many applications for ultrasonic sensors,
such as in intrusion alarm systems, automatic door
openers and backup sensors for automobiles.

9. FEATURES
 Object detection includes zero range objects
 2.5V to 5.5V supply with 2mA typical current draw
 Readings can occur up to every 50mS, (20-Hz rate)
 All interfaces are active simultaneously
 9600Baud rate
 It detect object from 0 inches to 254 inches with resolution of
1 inch
 Sensor operates at 42KHz
 Cost $ 25 per unit

10. ARM7TDMI PROCESSOR
The ARM7TDMI core is a member of the ARM family of
general-purpose 32-bit Microprocessors. The ARM family offers high
performance for very low power Consumption and small size. The
ARM architecture is based on Reduced Instruction Set Computer
(RISC) principles.
This simplicity gives:
 A high instruction throughput
 An excellent real-time interrupt response
 A small, cost-effective, processor macro cell.

11. OVERVIEW OF LPC2129 MICROCONTROLER:

12. Technical specification
Program Flash 256 KB
Clock Crystals • 12.0000 MHz crystal for maximum
execution speed and standard CAN bit
rates (5 x PLL = 60 Mhz CPU clock)
Dimensions 55 x 58 mm
Power On-board low-dropout voltage and
reset generation
• Generates +3.3V and +1.8V from a
+5V supply
• +3.3V available for external circuits,
up to 300 mA
• Power supply: 5 VDC
Data Memory
16 KB

13. CAN CONTROLER:
 Controller Area Network (CAN) is an advanced serial bus system that efficiently
supports distributed control system with a very high level of security
 With the use of CAN, point - to - point wiring is replaced by one serial bus
connecting to all control systems
 The CAN protocol uses the data link layer and the physical layer in the ISO_OSI
model
 The CAN protocol handle bus accesses according to the concept called “Carrier
Sense Multiple Access with arbitration on message priority ". This arbitration Concept
avoids collisions of messages whose transmission was started by more than one node
simultaneously and makes sure the most important message is sent first without time loss
 If two or more bus nodes start their transmission at the same time after having found
the bus to be idle, collision of the messages is avoided by bitwise arbitration. Each node
sends the bits of its message identifier and monitors the bus level

14.  In CAN protocol, two versions are available. They are version
2.0A CAN and version 2.0B CAN. Version 2.0A is original CAN
specifications specify an 11 bit identifier which allows 2^11(=2048)
different message identifiers and is known as standard CAN. Version
2.0B CAN contain 29 bit identifiers which allows 2^29 (over 536
million) message identifiers
 CAN has the following properties:
 Prioritization of messages
 Guarantee of latency times
 Configuration flexibility
 Multicast reception with time synchronization
 System wide data consistency
 Error detection and error signaling

15. Message Priority Assignments (Reprinted from
ISO 11783-3 5.2.1):
Priority Field Number Priority Level
000 0 - Highest
001 1
010 2
011 3
100 4
101 5
110 6
111 7 – Lowest

18. APPLICATION:
 Used as a Warning System to avoid Collision in National Highways
 Used by Police to Track the speed of the approaching vehicles
Used to detect an object in Extreme conditions like Fog and misty areas
 Can be implemented in Robotic Applications
 Can be used in large vehicles like Trucks and buses
 Can be implemented in Aircraft and aerospace electronics
 Can be used in Passenger and cargo trains

19. CONCLUSION
This project CAN BASED ACCIDENT AVOIDANCE
SYSTEM is intended for secure and smooth journey. The car/
vehicle itself is aware of its movement. If the driver himself is
not concentrating on driving or any other parameters, which
may cause damage to vehicle as well a life, this intelligent car/
vehicle warn the driver regarding the danger ahead