Automatic Railway Track Control

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AUTOMATIC RAILWAY TRACK CONTROL

A PROJECT REPORT

Submitted by

M.GOSPELSON (71005114011)

V.POONGUNDRAN (71005114031)

A.SIVASHANKAR (71005114051)

P.NIKHIL (71005114307)

in partial fulfillment for the award of the degree

of

BACHELOR OF ENGINEERING

IN

MECHANICAL ENGINEERING

KARPAGAM COLLEGE OF ENGINEERING

ANNA UNIVERSITY: CHENNAI 600 025

MAY 2008

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ANNA UNIVERSITY: CHENNAI 600 025

BONAFIDE CERTIFICATE

Certified that this project report “AUTOMATIC RAILWAY

TRACK CONTROL” is the bonafide work of “M.GOSPELSON,

V.POONGUNDRAN, A.SIVASHANKAR, P.NIKHIL”who

carried out the project work under my supervision.

SIGNATURE SIGNATURE

Dr.S.CHARLES Mr.E.BABURAJ

PROJECT GUIDE

HEAD OF THE DEPARTMENT PROFESSOR

MECHANICAL ENGINEERING MECHANICAL ENGINEERING

KARPAGAM COLLEGE OF KARPAGAM COLLEGE OF

ENGINEERING ENGINEERING

OTHAKKALMANADAPAM POST, OTHAKKALMANADAPAM POST,

COIMBATORE – 641 032. COIMBATORE – 641 032.

Submitted by the university examination VIVA-VOCE held on _________

Internal Examiner External Examiner

ACKNOWLEDGEMENT

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We express our sincere thanks to our respected principal

Dr.K.M.MohanaSundaram for the support he intended in carrying out the

project. We record gratitude to our Head of the Department Dr.S.Charles

for the help and support he extended during the complete phase of the

project. We are happy to owe our sincere thanks coupled with deep sense of

gratitude to our project guide Mr. E.BABURAJ for his enlighten persuasion

at every stage which helped us to bring out this project a successful one. We

also thank our project coordinator Mr.C.KRISHNARAJ for his constant

support.

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CONTENTS

CHAPTER TITLE PAGE NO

1 SYNOPSIS 1

2 INTRODUCTION 2

3 WORKING PRINCIPLE 4

4 BLOCK DIAGRAM 8

5 MICRO CONTROLLER 9

6 ENCODER 12

7 DECODER 13

8 RF TRANSMITTER 14

9 RF RECEIVER 16

10 CIRCUIT DIAGRAM 18

11 RELAYS 20

12 POWER SUPPLY 22

13 APPLICATION & ADVANTAGES 24

14 COST ESTIMATION 26

15 CONCLUSION 27

16 BIBLIOGRAPHY 28

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LIST OF DIAGRAMS

NO TITLE PAGE NO

1. BLOCK DIAGRAM 8

2. MICRO CONTROLLER 11

3. ENCODER CIRCUIT 12

4. DECODER CIRCUIT 13

5. RF.TRANSMITTER CIRCUIT 14

6. RF RECEIVER CIRCUIT 16

7. TRANSMITTER AND RECEIVER CIRCUIT 18

8 RELAY CIRCUIT 21

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SYNOPSIS

The project titled “AUTOMATIC RAILWAY TRACK CONTROL”

is based on Micro controller 89c51 for track changing in railways.

Presently track changing is done manually or with the help of

motors.Due to this, manual errors may take place. To overcome this

problem, automation in track changing is done.In this project the command

given by the system (magnet) is encoded by a micro controller and transmits

via Radio Freqency transmitter.The system placed near the track receives the

data and decodes it using another micro controller and decoder. This micro

controller will activate the corresponding relay according to the program and

the motor works.Limit switches are used to stop the motor.

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INTRODUCTION

The project “AUTOMATIC RAILWAY TRACK CONTROL’ is

aimed at providing full automation of railways. Also to provide secured

railway transportation.

The main components are

1. Micro controller

2. Encoder

3. Decoder

4. Radio Frequency transmitter

5. Radio Frequency receiver

6. Limit switches

7. DC motor

8. Magnetic sensor

MICRO CONTROLLER

The micro controller used is of 89c51 series. The main feature

of 89c51 micro controller is that it has a 8 Bit CPU optimized for control

application. Also it has a bi-directional and individually addressable I/O

lines.

ENCODER

Encoder is a combinational logic circuit that performs reverse

encoder function. It accepts an active level on one of its input and produce

an output code.

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DECODER

Decoder is a logic circuit that accepts sets of inputs that

represents a binary number and activates only the output that corresponds to

that input number.

RF TRANSMITTER

The RF transmitter transmits the received signal to the receiver

circuit placed near the track changer. The range of this transmitter lies

between 100 to500 meters.

RF RECEIVER

It receives the signal from the transmitter.

LIMIT SWITCHES

Limits switches are used to stop the running motor.

The need of this project is to avoid manual errors in track

changing. The magnetic sensor placed on the track activates the RF

transmitter. The transmitter in turn sends the signal from the train to the

system placed near the track changer. The system decodes and transmits the

signal to the micro controller and the micro controller activates the relay

switches there by the motor works and the track changes. This concept can

be directly applied to the real track system.

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WORKING PRINCIPLE

The project Automatic Wireless Railway track control is mainly

based on micro controller 89c51. As the name suggests it is concerned with

automatic changing of railway track.

Here there are two circuits; one of them is located on the train

and the other one near the place of track change. The circuit on train consists

of a micro controller, encoder, and an ‘RF’ transmitter. The consists various

codes for different trains. These codes are transmitted to the micro

controller. The micro controller sends these codes to the encoder, which

converts it into digital form. These digital signals are transmitted to another

circuit placed near the track by and ‘RF’ transmitter.

The circuit placed near the track consists of ‘RF’ receiver,

decoder, limit switches, micro controller, relay drivers and a motor. The

‘RF’ receivers receive the digital datas sent by the train and transmit it to

the decoder, which decodes the codes into analog form. These codes are

then fed to the micro controller. The micro controller controls the relay

drivers to drive the motors. The limits switches are provided to control the

DC motor.

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PROGRAM

// controlling a stepper motor

#include <stdio.h> //

#include <reg420.h> //

#include <ctype.h> //

#include "serial.h"

void main()

char o;

int i;

InitSerialHardware();

do

o = getchar();

if(isspace(o)) continue;

o = toupper(o);

if(o == 'S')

puts(" Stop");

P1 = 0;

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if (o == 'L')

puts(" Left");

TMOD = 0x20;

TCON = 0x40;

TH1 = 0xF9;

TL1 = 0xF9;

PCON = 0x80;

SCON0 = 0x50;

if (o == 'R')

puts(" Right");

SCON0 = 0x50;

PCON = 0x80;

TL1 = 0xF9;

TH1 = 0xF9;

TCON = 0x40;

TMOD = 0x20;

else continue;

while (1); /*continues loop */

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printf("a"); // transmit a along with CR & LF.

For stopping the motor

if(o == 'S')

puts(" Stop");

P1 = 0;

goto exit; //put this label at the end of program with a while(1) loop.

//before the last braces of main function

exit:

while(1);

//this will stop

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BLOCK DIAGRAM

TRANSMITTER CIRCUIT

RECEIVER CIRCUIT

Magnetic

Sensor

Micro

controller

Encoder

RF TX

RF RX

Decoder

Limit Switch

Limit Switch

Relay Driver

Relay Driver

Micro

controller

Motor

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MICRO CONTROLLER

INTRODUCTION

A Micro Controller consists of a powerful CPU tightly coupled with

memory RAM, ROM, or EPROM, various I/O features such as Serial

ports, Parallel Ports, Timer/ Counters, Interrupt Controller, Data

Acquisitions interfaces- Analog to Digital Converter (ADC), Digital to

Analog Converter (ADC), everything integrated onto a single Silicon Chip.

It does not mean that any micro controller should have al the above

said features on chip, Depending on the need and area of application for

which it is designed. The on chip features present in it may or may not

include all the individual section said above.

Any microcomputer system requires memory to store a sequence of

instructions making up a program, parallel port or serial port for

communicating with an external system, timer/ counter for control purpose

like generating time delays, Baud rate for the serial port, apart from the

controlling unit called the Central Processing Unit.

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ADVANTAGES OF MICROCONTROLLERS

1. If a system is developed with a microprocessor, the designer has to

go for external memory such as RAM, ROM or EPROM and

peripherals and hence the size of the PCB will be large enough

to hold all the required peripherals . But, the micro controller has got all

these peripheral facilities on a single chip so development of a similar

system with a micro controller reduces PCB size and cost of the design.

One of the major differences between a micro controller and a

microprocessor is that a controller often deals with bits, not bytes as in the

real world application, for example switch contacts can only be open or

close, indicators should be lit or dark and motors can be either turned on or

off and so forth.

INTRODUCTION TO ATMEL MICROCONTROLLER

SERIES : 89C51 Family, TECHNOLOGY: CMOS

The major Features of 8- bit Micro controller ATMEL 89C51:

• 8 Bit CPU optimized for control applications

• Extensive Boolean processing (Single – bit Logic ) capabilities

• On- Chip Flash Program Memory

• On- Chip Data RAM

• Bi- directional and Individually Addressable I/O Lines

• Multiple 16- Bit timer / Counters

• Full Duplex UART

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• Multiple Source/ Vector/ Priority Interrupt Structure

• On- Chip Oscillator and clock circuitry.

• On- Chip EEPROM

• SPI Serial Bus Interface

• Watch Dog Timer

MICROCONTROLLER CIRCUIT

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ENCODER

An encoder is a combinational logic circuit that performs reverse

decoder function and encoder accepts an active level on one of its input and

produce an output code.

An encoder has a number of input lines only one of which is activated

at a given time and produces an N bit output code depending on which input

is activated.

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DECODER

A decoder is a logic circuit that accepts sets of inputs that represents a

binary number and activates only the output that corresponds to that input

number. In other words decoder looks at its input and determines which

binary number is present there and activities the one output that corresponds

to that number all other output remains deactivate.

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RF TRANSMITTER

Circuit operation

RF transmitter circuit is given. This circuit can be operated on a 9V

D.C Supply source. The signals are passed on from the signal unit

connected in the circuit to the base of the transistor Q1(BF494) through the

capacitor C1 (0.1). Q1 is a NPN transistor and its collector is given positive

supply through the coil L1.Its emitter is connected to the ground through

the resistance R3 (100E) while its base is given the forward supply through

the resistance R2 (68K). Other than this, the signal unit is given the positive

supply through the resistance R1 (1k8). This resistance functions as the

load resistance here and generates the audio signals together with the signal

unit. These audio signals are given to the base of the transistor Q1 (BF494)

through the capacitor C1(0.1).

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The coil L1 connected at its collector can be made by giving 5 turns

of 24 SWG wire on a base of 0.5 cm diameter. A capacitor C3 (12pf) has

also been connected between the collector and the emitter of the transistor

Q1. This capacitor triggers the oscillations. As soon as the audio signal is

received at the base then the transistor starts to oscillate and it generates

Radio frequency, which is given to the antenna through the capacitor C4

(1kpf ) and transmitted. The range of this transmitter lies between

100meters to 500 meters.

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RF RECIEVER

Circuit Operation

IC CxA1019S is 30-pin DIL IC manufactured by Sony, Facility to

connect a tuning indicator has also been provided in this IC apart from the

various sections built within the IC. A 10.7MHz ceramic filter has been used

in this circuit in place of the IFTs. This is a single chip AM/FM Radio IC.

An audio output section is also built within the IC apart from all the

necessary sections for the AM/FM radio. The signal at the IC pin no.24 is

given to the pin-1 of the volume control and the pin 2 of the volume control

is connected to the audio output section. This section is not shown in the

given circuit.

The IC pin no.27 is the positive supply pin, which is given +6V

supply through a resistance R4 (56E). This supply is filtered by the

capacitor C1 (1000MF/16V). IC pin no.7 &8 are connected to the oscillator

section and a coil L1 is connected at the pin no.8. A capacitor C3 (39PF) and

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a button trimmer B1 (15pf) are connected parallel to this coil L1. This

trimmer selects the desired frequency. RF coil L2 is connected at the IC pin

no.10 and a capacitor C7 (33pf) and a button trimmer B2(15pf) are

connected in parallel to this coil.

IC pin no.9 is the RF ground pin. RF coils, the oscillator and the

related components are all connected at this pin. Antenna coil L3 is

connected at the IC pin.no.13 through a capacitor C9 (lkpf) and a capacitor

C10 (27pf) is connected in parallel to this coil. A telescopic antenna is

connected from the center point of the capacitor C9 and coil L3. Tuning

indicator LED is connected to it for filtration. Positive supply is given to the

anode of the LED through a resistance R3 (920E). The IC pin no.

1,2,3,4,5,12,14,19,21 and 30 are the dc ground pins. IC pin no.9 is the RF

ground pin.

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TRANSMITTER

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RECEIVER

R.F. RECEIVER

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RELAYS

A relay is a switch worked by an electromagnet. It is useful if we want

a small current in one circuit to control another circuit containing a device

such as a lamp or electric motor which requires a large current, or if we

wish several different switch contacts to be operated simultaneously.

When the controlling current flows through the coil, the soft iron core

is magnetized and attracts the Lo shaped soft iron armature .This rocks on

its pivot and opens, closes or changes over, the electrical contacts in the

circuit being controlled it closes the contacts.

The current needed to operate a relay is called the pull- in current and

the dropout current in the coil when the relay just stops working. If the coil

resistance R of a relay is 185Ω and its operating voltage V is 12V, the pull-

in current I is given by:

I = V = 12 =0.065A= 65mA

R 185

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RELAY CIRCUIT

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POWER SUPPLIES

The ac voltage, typically 220V rms, is connected to a transformer,

which steps that ac voltage down to the level of the desired dc output. A

diode rectifier then provides a full- wave rectified voltage that is initially

filtered by a simple capacitor filter to produce a dc voltage. This resulting dc

voltage usually has some ripple or ac voltage variation.

A regulator circuit removes the ripples and also remains the same dc

value even if the input dc voltage varies, or the load connected to the output

dc voltage changes. This voltage regulation is usually obtained using one of

the popular voltage regulator IC units.

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+5V POWER SUPPLY

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APPLICATION

1. It can be used at major railway crossings

2. It can be applied were there is an heavy rail traffic

3. Can be made as an integral part of metro railways.

4. Can be made as a part of complete automation & modernization of

railway system.

ADVANTAGES

1. Reduction of railway accidents.

2. Avoid manual error in track changing

3. Reduction of reasonable delay in train timings

4. Less cost of manufacturing & more accurate in function .

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COST ESTIMATION

Materials required for Structure : Rs. 170.00

Purchase of Electric Goods : Rs.1758.00

Circuit Elements : Rs. 640.00

Paint Materials : Rs. 150.00

Miscellaneous : Rs.2000.00

Total Material Cost : Rs.4718.00

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ESTIMATION OF LABOUR COST

Soldering : Rs.20.00

Cutting : Rs.20.00

Drilling : Rs.50.00

Welding : Rs.50.00

Painting : Rs.60.00

Assembling : Rs.200.00

Table Labour Cost : Rs.400.00

Total Cost : Cost Estimation + Labour Cost

: 4718 +400

: Rs.5118.00

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CONCLUSION

Thus this project has tremendous potential in the field of rail

transportation. By this project we can ensure safe journey for the

passengers. This project can be modified easily and has great

potential for up

gradation.

FUTURE ENHANCEMENTS

The system can be used operate multiple tracks. We can increase

the range of signal transmission .This system can be also be used to

record the information of train passed. Alarm signals can be in

planted.

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BIBLIOGRAPHY

REFERENCE BOOKS

1. Electronic Circuits: fundamentals applications by Mike Tony

2. Power electronics by S.K.Raja

3. Encoders and Decoders by Carl James

4. PSG design data book

WEBSITES

1. Wikipedia.org

2. Microcontroller.com

3. Atmel.com