Vehicle Anti Collision Using Ultrasonic Signals

VEHICLE ANTI COLLISION USING ULTRASONIC SIGNALS

ABSTRACT:

The aim of the project is to avoid vehicle collision. Nowadays so many accidents are

happening in the roads. This will create time loss for passengers, huge traffic in the road

and life loss for the accident person and vehicle damage. We can avoid these things by

using ultrasonic anti-collision instrument. This instrument is fixed in front side of the

vehicle. If any vehicle comes near by this vehicle immediately this instrument will give

alarm and it will stop the vehicle.

COMPONENTS USED

Power Supply : 5v DC

Micro controller : AT89S52

Buzzer : Freq-1 to 18 kHz (5v-12Vdc)

LCD : 2*16 characters

Relay

Ultrasonic transmitter and receiver.

SOFTWARE USED:

Embedded C

WORKING PRINCIPLE

The vehicle collision can be avoided by using this project. Opposite vehicles are sensed

by using ultrasonic signals. The microcontroller switching on the ultrasonic transmitter

and receive the output signal of ultrasonic receiver. By doing distance measurement

calculation the system can find out the distance of opposite vehicle from our vehicle. If

the distance is our set value, the controller will energize braking system. The buzzer will

give warning beep. The beep duration is depends upon the distance between the two

vehicles.

BLOCK DIAGRAM

COMPONENT APPLICATIONS:

POWER SUPPLY:

The microcontroller and other devices get power supply from AC to Dc adapter through

voltage regulator. The adapter output voltage will be 12V DC non regulated. The 7805

voltage regulators are used to convert 12 V to 5VDC.

DC OutputAC Power

AC/DC Adapter

Regulator (7805)

Filter

Micro Controller (AT89S52)

Relay Driver

RELAY

Buzzer

Buzzer Driver

Buzzer OSC

LCD (Display)

LCD Glass

LCD Driver

Battery

Ultrasonic Transmitter

Ultrasonic Receiver

Brake System

Vital role of power supply in ‘Vehicle anti-collision using ultrasonic signals’

The adapter output voltage will be 12V DC non regulated. The 7805/7812 voltage

regulators are used to convert 12 V to 5V/12V DC.

MICRO CONTROLLER-AT89S52

The AT89S52 is a widely available in market, cost effective, low power and high-

performance CMOS 8-bit microcontroller with 8K bytes of in-system programmable

Flash memory. The device is manufactured using Atmel’s high-density nonvolatile

memory technology and is compatible with the industry- standard 80C51 instruction set

and pin out.

Features:

8K Bytes of In-System Programmable (ISP) Flash Memory

Endurance: 1000 Write/Erase Cycles

4.0V to 5.5V Operating Range

256 x 8-bit Internal RAM

32 Programmable I/O Lines

Full Duplex UART Serial Channel

Fully Static Operation: 0 Hz to 33 MHz

Description

The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller

with 8K bytes of in-system programmable Flash memory. The device is manufactured

using Atmel’s high-density nonvolatile memory technology and is compatible with the

industry- standard 80C51 instruction set and pin out. The on-chip Flash allows the

program memory to be reprogrammed in-system or by a conventional nonvolatile

memory programmer. By combining a versatile 8-bit CPU with in-system programmable

Flash on a monolithic chip, the Atmel AT89S52 is a powerful microcontroller, which

provides a highly-flexible and cost-effective solution to many, embedded control

applications. The AT89S52 provides the following standard features: 8K bytes of Flash,

256 bytes of RAM, 32 I/O lines, Watchdog timer, two data pointers, three 16-bit

timer/counters, a six-vector two-level interrupt architecture, a full duplex serial port, on-

chip oscillator, and clock circuitry. In addition, the AT89S52 is designed with static logic

for operation down to zero frequency and supports two software selectable power saving

modes. The Idle Mode stops the CPU while allowing the RAM; timer/counters, serial

port, and interrupt system to continue functioning. The Power-down mode saves the

RAM contents but freezes the oscillator, disabling all other chip functions until the next

interrupt or hardware reset.

3.1.3 Pin Configuration:

Fig (3.1)

3.1.3.1 Descriptions of the pins being used:

RxD / P 3.0 (Pin 10):

This pin is used for receiving data serially during serial communication. This pin is

connected to RxD (Pin 12) of MAX 232.

TxD / P 3.1 (Pin 11):

This pin is used for transmitting data serially during serial communication. This pin is

connected to TxD (Pin 11) of MAX 232.

INT0 / P 3.2 (Pin 12):

This pin is used to receive laser signal. Laser receiver is connected to this pin.

INT1 / P 3.3 (Pin 13):

This pin is used to send laser signal. Laser transmitter is connected to this pin.

P 3.4 – P 3.7 (Pin 14 – 17):

These pins are used to send data sequence to rotate the stepper motor in clock wise

and anti clock wise direction.

XTAL1 and XTAL2 (Pin 19 and Pin 18):

These two pins are used to connect external quartz crystal to microcontroller.

Vss (Pin 20):

This pin is connected to ground.

EA / Vcc (Pin 31):

This pin is connected to Vcc, because the chip contains internal ROM.

P 0.7 (Pin 32):

This pin is used to make the buzzer produce audible sound. This pin is connected to

buzzer.

P 0.2 – P0.5 (Pin 34 – 37):

These pins are used to transfer data from microcontroller to LCD 16 * 2.

These pins are connected to Pins 11 –14 of LCD 16 * 2.

P 0.1 (Pin 38):

This pin is used to enable LCD 16 * 2. This pin is connected to pin 6 of

LCD 16 * 2.

P 0.0 (Pin 39):

This pin is used to select the register of LCD 16 * 2. This pin is connected to pin 4 of

LCD 16 * 2.

Vcc (Pin 40):

This pin is used to provide power supply for microcontroller. This pin is connected to

+5 volts.

3.1.4 Specifications of our project:

In this project we are using Timer 1 in mode 2. As mode 2 is an auto reload mode.

M1=1 and M0=0

TMOD:

Timer 1 Timer 0

GATE C/T M1 M0 GATE C/T M1 M0

0 0 1 0 0 0 0 0

To communicate serially, the baud rate has to be set. In our project configuring the

TMOD and SCON registers is setting a baud rate of 2400bps.

To generate a baud rate of 2400 bps, the TH1 is loaded with 0xf4(decimal value: -3).

And then Timer 1 should be started by making TR1 = 1.

SM0 SM1 SM2 REN TB8 RB8 TI RI

0 1 0 1 0 0 0 0

SCON:

Here SCON register is assigned a value 50H.

That is we are using serial mode 1 hence SM0=0 and SM1=1. Since we want the

microcontroller to both transfer and receive data, REN must be set to 1.

3.1.5 Block Diagram

.

Fig (3.2)

Vital role of Micro controller-AT89S52 in ‘Vehicle anti-collision using ultrasonic

signals’

The microcontroller switching on the ultrasonic transmitter and receive the output signal

of ultrasonic receiver. By doing distance measurement calculation the system can find out

the distance of opposite vehicle from our vehicle. If the distance is our set value, the

controller will energize braking system.

Oscillator and Clock circuit:

The heart of the 89s52 is the circuitry that generates the clock pulses by which all

internal operations are synchronized. Pins XTAL1 and XTAL2 are provided for

connecting a resonant network to form an oscillator. Typically, a quartz crystal and

capacitors are employed as shown in figure. The crystal frequency is the basic

internal clock frequency of the micro controller.

To calculate the time any particular instruction will take to be executed the

number of cycle, C needs to be found out, the time to execute that instruction is then

found by multiplying C by 12 and dividing the product by the crystal frequency:

T inst = (C*12d)/(crystal frequency)

An 11.0592 MHz crystal is connected to XTAL1 and XTAL2 to yield a cycle

frequency of 921.6 KHz, which can be divided evenly by standard communication

rates of 19200, 9600, 4800,2400, 1200, and 300 Hz.

3.1.7 Memory Organization

89s52 devices have a separate address space for Program and Data Memory. Up

to 64K bytes each of external Program and Data Memory can be addressed.

3.1.7.1 Program Memory

If the EA pin is connected to GND, all program fetches are directed to external

memory. On the AT89S52, if EA is connected to VCC, program fetches to addresses

0000H through 1FFFH are directed to internal memory and fetches to addresses 2000H

through FFFFH are to external memory.

3.1.7.2 Data Memory

The AT89S52 implements 256 bytes of on-chip RAM. The upper 128 bytes

occupy a parallel address space to the Special Function Registers. This means that the

upper 128 bytes have the same addresses as the SFR space but are physically separate

from SFR space. When an instruction accesses an internal location above address 7FH,

the address mode used in the instruction specifies whether the CPU accesses the upper

128 bytes of RAM or the SFR space. Instructions, which use direct addressing access of

the SFR space. For example, the following direct addressing instruction accesses the SFR

at location 0A0H (which is P2).

MOV 0A0H, #data

Instructions that use indirect addressing access the upper 128 bytes of RAM. For

example, the following indirect addressing instruction, where R0 contains 0A0H,

accesses the data byte at address 0A0H, rather than P2 (whose address is 0A0H).

MOV @R0, #data

Note that stack operations are examples of indirect addressing, so the upper 128 bytes of

data RAM are available as stack space.

3.2 LIQUID CRYSTAL DISPLAY (LCD)

LCD is a single-line, 16-character unit. This is a standard unit available in market.

Interface with micro controller is accomplished via four data lines D7-D4 & two control

lines RS & EN. Using these six lines, micro controller displays all messages & telephone

numbers. The signal names used here are the same as used by the LCD module/driver

manufacturers.

Some LCD modules come with additional one or two pins. These extra pins are

used for backlighting. There is no fixed standard for the additional pins. LCD controller

is a flexible controller & can be used with 8-bit or 4-bit micro controller. In 4-bit mode,

only D4-D7 are used, leaving D0-D3 open.

To avoid problems, extra delays in software are provided after every write

command so that before writing another command/data, LCD module should be ready

(not busy). Further, only four data lines (D4-D7) have been used while the other four data

lines (D0-D3) are left disconnected. Thus even though we are using an 8-bit micro

controller, the LCD module has been interfaced for 4-bit mode. Again, to save pin count,

RS line is shared with SDA (serial data) line for memory (IC3) since at any given

moment micro controller will either interface with the LCD module or the memory, and

this does not affect the system operation Liquid Crystal Displays have materials, which

combine the properties of both liquids and crystals. LCD consists of two glass panels,

with the Liquid Crystal material sand witched in between them. The inner surfaces of the

glass plates are coated with transparent electrodes, which define the character, symbols or

patterns to be displayed.

The LCDs are lightweight with only a few millimeters thickness. Since the LCDs

consume less power, they are compatible with low power electronic circuits and can be

powered for long durations. The LCDs don’t generate light and so light is needed to read

the display. By using backlighting, reading is possible in the dark. The LCDs have long

life and wide operating temperature range. A brighter display can be obtained by

providing backlighting.

LCD has single line display, Two-line display and four-line display.

Two-line display

LCDs can add a lot to your application in terms of providing an useful interface for the

user, debugging an application or just giving it a "professional" look. The most common

type of LCD controller is the Hitachi 44780 which provides a relatively simple interface

between a processor and an LCD. Using this interface is often not attempted by

inexperienced designers and programmers because it is difficult to find good

documentation on the interface, initializing the interface can be a problem and the

displays themselves are expensive. In our project we used two-line display.

Vital role of LCD in ‘Vehicle anti-collision using ultrasonic signals’

Used to display the distance between the vehicles.

80 8F

C0 CF

3.2.1 Microcontroller and LCD interactions:

Microcontroller interacts with LCD to display data on it. Port 0 pins are used

to

interact with the LCD.

P 0.0: is connected to Register Select (RS) pin i.e. Pin 4 of LCD.

If P 0.0 = 0, instruction commands code register is selected, allowing the user

to send a command such as clear display, cursor at home etc.

If P 0.0 = 1, the data register is selected, allowing the user to send data to be

displayed on to the LCD.

P 0.1:is connected to Enable (EN) pin i.e. Pin 6 of LCD.

The LCD to latch information presented on its data pins uses the enable pin.

When data is supplied to data pins, a high-to-low pulse must be applied to this

pin in order for the LCD to latch in the data present at the data pins. This pulse

must be a minimum of 450ns wide.

P 0.2: is connected to Data pin bit 0 (LSB) pin i.e. Pin 11 of LCD.




The microcontroller provides data on P 0.2 – P 0.5 pins to LCD.

P 0.5

P 0.4

P 0.3

P 0.2

P 0.1

P 0.0

Microcontroller

D7

D6

D5

D4LCD

EN

RS

Fig (3.3)

3.2.2 Hardware Configuration

The initial equates are

RS EQU P0.0 (PORT-0)

EN EQU P0.1

DATA0 EQU P0.2

DATA1 EQU P0.3

DATA2 EQU P0.4

DATA3 EQU P0.5

3.2.3 Interfacing the LCD

4-bit Interface Mode

Function set

RS RW DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 0 0 0 0 1 0 X X X X0 0 0 0 1 0 X X X X0 0 N F X X X X X X

Power on

Wait for more than 30ms after VDD rises to 4.5v

Wait for more than 3ms



Initialization end

3.2.3 Cursor addresses for LCD

16 x 2 LCD

80 81 82 83 84 85 86 through 8FC0 C1 C2 C3 C4 C5 C6 through CF

Display ON/OFF ControlRS RW DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB00 0 0 0 0 0 X X X X0 0 1 D C B X X X X

Display Clear

RS RW DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB00 0 0 0 0 0 X X X X0 0 0 0 0 1 X X X X

Entry Mode SetRS RW DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB00 0 0 0 0 0 X X X X0 0 0 1 I/D SH X X X X

BUZZER:

The buzzer subsystem produces a 2 KHz audible tone when powered. The buzzer will

sound when the signal coming into the driver is high. It must be connected to a transistor,

Darlington or transducer driver subsystem.

The buzzer is connected between the supply rail (+V) and the input signal. This acts as

load on the driver. When the input signal coming into the buzzer subsystem is low, a

potential difference across the buzzer causes current to flow. It is this flow of current

that causes the buzzer to sound.

Vital role of Buzzer in ‘Vehicle anti-collision using ultrasonic signals’

The buzzer will give warning beep. The beep duration is depends upon the distance

between the two vehicles.

RELAY:

http://www.marconiect.org/display.php?document_id=85



The relay subsystem is an electrically-operated switch. The relay switches when the

signal coming into the driver is high. It must be connected to a Darlington or transducer

driver subsystem.

The relay coil is connected between the supply rail (+V) and the input signal. This acts as

load on the driver. When the input signal coming into the relay subsystem is low, a

potential difference across the relay coil causes current to flow. It is this flow of current

that causes contacts to switch.

Vital role of Relay in ‘Vehicle anti-collision using ultrasonic signals’This is used to switch ON/OFF the brake unit. This operating voltage is 12V DC.

ULTRASONIC RAYS:

Ultrasonic is acoustic energy in the form of waves having a frequency above the human

hearing range. Ultrasonic can be used to locate objects by means similar to the principle

by which radar works. High-frequency acoustic waves reflect from objects, even

comparatively small ones, because of the short wavelength. The distance to an object can

be determined by measuring the delay between the transmission of an ultrasonic pulse

and the return of the echo.

Applications

Ultrasonic is used in electronic, navigational, industrial, and security applications.

It is also used in medicine to view internal organs of the body.

Ultrasonic security systems are also popular among automobile owners. These

devices detect motion in the immediate vicinity of a vehicle.

Ultrasonic is used in industry to analyze the uniformity and purity of liquids and

solids.

Ultrasonic is used to observe the condition and behavior of fetuses prior to birth.

Subminiature ultrasonic cleaning instruments are used by some dentists during

routine examinations.



Ultrasonic can be used in sonar systems to determine the depth of the water in a

location, to find schools of fish, to locate submarines, and to detect the presence

of SCUBA divers.

ULTRASONIC TRANSDUCER (Transmitter and Receiver)

Ultrasonic TXR is used to transmit ultra sonic signals. Ultrasound is used in electronic,

navigational, industrial, and security applications. It is also used in medicine to view

internal organs of the body. Ultrasound can be used to locate objects by means similar to

the principle by which radar works. High-frequency acoustic waves reflect from objects,

even comparatively small ones, because of the short wavelength. The distance to an

object can be determined by measuring the delay between the transmission of an

ultrasound pulse and the return of the echo.

APPLICATIONS OF THIS PROJECT:

Distance measurement

Vehicle anti-collision

SOFTWARE DETAILS

6.1 Keil u Vision 2 IDE:

Keil u Vision 2 IDE (Integrated Development Environment) is a windows based

front end for the C compiler and assembler. Keil u Vision 2 is used for writing embedded

C programs.

Embedded C is a high level language, which includes many aspects of ANSI C

programming Language. Standard libraries are altered or enhanced to add the

peculiarities of an embedded target processor.

6.2 C x 51 cross compiler:

C X 51 is a cross compiler to compile C program for your target 89s52

environment and provides several extensions to ANSI standard C to support the elements

of 89s52 architecture. These C programs are referred as embedded C program.

The software used to program Kiel u Vision 2 embedded C is a high level language,

which includes many aspects of the ANSI C programming language.

Documents

Vehicle Anti Collision Using Ultrasonic Signals