ANTI-COLLISION SYSTEM FOR RAILWAYSPROJECT

ACKNOLEDGEMENT

First we would like to thank the omniscient, omnipotent, omnipresent God

by virtue of whom we are able to complete this project.

We are grateful to Mrs. Anamika Bhatia, our head of department for her

valuable guidance, support and co-operation extend by her. Then we would

like to thank Colonel Rakesh Sharma sir and our project coordinator and co-

coordinator for their kind cooperation, help and never ending support. We

would also like to thank Mr. Sudakar chauhan sir without whom our

project would not have been successful in all means.

We are also thankful to Mr. Kamal Ghanshala (Chairman, GEU Dehradun)

for providing us labs and facilities which proved to be very useful for our

project.

In the end, we convey our sincere thanks to all those people who directly or

indirectly helped us.

Aman Pant

Amit Bharti

Kumar Govind

1

ABSTRACT

In the recent time, we have seen a lot of railway accidents and yet Indian

Railways have not implemented any effective Anti-Collision System which

can avoid such type of accidents.

So, we come up with a project “Anti-Collision System (Railways)” which

can avoid such type of railway accidents.

In this project, we have used Microcontroller, LCD panel, Wireless

TransReceiver Unit (Zigbee), MAX 232, different IC’s and power supply.

Microcontroller is the heart of our project, it acts as an interface among

LCD, Motor, Max 232,Potentiometer,LED’s and Transreceiver (Zigbee).

2

CONTENTS

TABLE OF CONTENTS

1. Introduction

1.1 Introduction of project……….……………………………..….….9

2. Block Diagram……………..…………………………..……………10

2.2.1 Transmitter…………..…………………………………..…..102.2.2 Reciever…………………………………………………….. 11

3. Simulation Diagram……………………………………………….13

4. PCB Layout…………………………………..……………..………14

5. Components Description

5.1ATMEGA 8............................................................................16

5.2PIN DIAGRAM……………………………………………...19

5.3Block Diagram……………………………………………….20

5.4PIN Description………………………………………………21

6 TRANSISTOR………………………………………………………….26

7 TRANSRECIEVER…………………………………………………….27

8 LED……………………………………………………………………..30

9 CAPACITOR…………………………………………………………...31

10 DIODE………………………………………………………………….34

11 RESISTOR……………………………………………………………...37

12 MOTOR...………………………………………………………………39

13 LCD……………………………………………………………………..40

3

14 MAX 232……………………………………………………………….41

15 IC 7805………………………………………………………………….42

16 WORKING……………………………………………………………..43

17 Bibilography and refrence………………………………………………44

4

INTRODUCTION

The idea of antiocollision system for railways clicked to our mind,because

we have seen a lot of railway accidents recently in the past,yet railways have

not implemented any such system in their railway network.altough konkan

railway have patented a anticollison system and that is expected to come in

picture in 2014 still that is specifically meant for deccan railways and

doesn’t cater the need of whole Indian railway network.

17 rail accidents was reported in 2010 in which 5 alone takes place in UP

due to dense fog condition,out of which in 19 July 2010 – Sainthia train

collision occurred in Sainthia, West Bengal, India, when the Uttar Banga

Express collided with the Vananchal Express. Casualties stand at 63 people

dead and more than 165 people injured, with many still trapped in wreckage

and 8 May 2010 – West Bengal, the Gyaneshwari Express train collision, a

suspected Naxalite terrorist attack kills at least 170 people, was the

disastrous one.

To prevent such rail accidents and to provide safety to the millions of

passengers who suffer daily from trains we come up with the idea of

anticollision system for railways, it not only warns driver before condition of

collision but also automatically stop the train to prevent such collision.

5

BLOCK DIAGRAM

TRANSMITTER

L C D

6

ATMEL (8µC)

L C D MOTOR

SWITCHES

POTENTIOMETER

BATTERY

TRANSCEIVER

MAX 232

ATMEL (8 µc )

MAX 232

MOTOR

MAX 232

TRANSRECEIVER

RECEIVER

COMPONENTS USED

S.No Name Of Component Value/Type Quantity1. Microcontroller ATMEL 8 22. LCD Hitachi HD44780 23. Transistor 2N2222A 24. Crystal Oscillator 14.7456MHz 25. Driver/Receiver MAX-232 26. Transreceiver ZigBee 27. Voltage Regulator IC 7805 28. Potentiometer 100K 29. D.C Motor 6-12V 210. Electrolytic Capacitor 10µF,1000µF 8,211. Ceramic Capacitor 33µF 412. LED Red,Blue,Green 2,2,213. Diode 1N4007 214. Resistor .330K,1K 4,615. Switch Button,DPDT 4,216. Connector Programmable 117. Wires

7

BATTERY

SWITCHESPOTENTIOMETER

SIMULATION DIAGRAM

8

PCB LAYOUT(TOP VIEW)

PCB LAYOUT(BOTTOM VIEW)

9

10

COMPONENTS DESCRIPTION

ATMEGA 8

Features

• High-performance, Low-power AVR®

- 8-bit Microcontroller

• Advanced RISC Architecture

– 130 Powerful Instructions – Most Single-clock Cycle Execution

– 32 x 8 General Purpose Working Registers

– Fully Static Operation

– Up to 16 MIPS Throughput at 16 MHz

– On-chip 2-cycle Multiplier

• High Endurance Non-volatile Memory segments

– 8K Bytes of In-System Self-programmable Flash program

memory

– 512 Bytes EEPROM

– 1K Byte Internal SRAM

– Write/Erase Cycles: 10,000 Flash/100,000 EEPROM

– Data retention: 20 years at 85°C/100 years at 25°C (1)

– Optional Boot Code Section with Independent Lock Bits

11

• In-System Programming by On-chip Boot Program

– True Read-While-Write Operation

– Programming Lock for Software Security

• Peripheral Features

– Two 8-bit Timer/Counters with Separate Prescaler, one compare

•Six Channels 10-bit Accuracy

– Byte-oriented Two-wire Serial Interface

– Programmable Serial USART

– Master/Slave SPI Serial Interface

– Programmable Watchdog Timer with Separate On-chip

•Oscillator

– On-chip Analog Comparator

•Special Microcontroller Features

– Power-on Reset and Programmable Brown-out Detection

– Internal Calibrated RC Oscillator

– External and Internal Interrupt Sources

– Five Sleep Modes: Idle, ADC Noise Reduction, Power-save

•I/O and Packages

– 23 Programmable I/O Lines

– 28-lead PDIP, 32-lead TQFP, and 32-pad QFN/MLF

12

•Operating Voltages

– 2.7 - 5.5V (ATmega8L)

– 4.5 - 5.5V (ATmega8)

•Power Consumption at 4 Mhz, 3V, 25°C

– Active: 3.6 mA

– Idle Mode: 1.0 mA

– Power-down Mode: 0.5 µA

13

Pin Configurations

The ATmega8 is a low-power CMOS 8-bit microcontroller based on the

AVR RISC architecture.

By executing powerful instructions in a single clock cycle, the ATmega8

achieves throughputs approaching 1 MIPS per MHz, allowing the system

designer to optimize power consumption versus processing speed.

14

BLOCK DIAGRAM

15

Pin Descriptions

VCC :-Digital supply voltage.

GND:- Ground.

16

Port B(PC7..PB0) :- is an 8-bit bi-directional I/O port with internal pull-up

resistors (selected for each bit). The Port B output buffers have symmetrical

drive characteristics with both high sink and source capability. As inputs,

Port B pins that are externally pulled low will source current if the pull-up

resistors are activated. The Port B pins are tri-stated when a reset condition

becomes active,even if the clock is not running.

Port C (PC5..PC0) :- Port C is an 7-bit bi-directional I/O port with internal

pull-up resistors (selected for each bit). The Port C output buffers have

symmetrical drive characteristics with both high sink and source capability.

As inputs, Port C pins that are externally pulled low will source current if

the pull-up resistors are activated. The Port C pins are tri-stated when a reset

condition becomes active, even if the clock is not running.

Port D (PD7..PD0) :- Port D is an 8-bit bi-directional I/O port with internal

pull-up resistors (selected for each bit). The Port D output buffers have

symmetrical drive characteristics with both high sink and source capability.

As inputs, Port D pins that are externally pulled low will source current if

the pull-up resistors are activated. The Port D pins are tri-stated when a reset

condition becomes active,even if the clock is not running.

RESET (Reset input):- A low level on this pin for longer than the

minimum pulse length will generate a reset, even if the clock is not running.

The Shorter pulses are not guaranteed to generate a reset.

17

AVCC:- AVCC is the supply voltage pin for the A/D Converter, Port C

(3..0), and ADC (7..6). It should be externally connected to VCC, even if the

ADC is not used. If the ADC is used, it should be connected to VCC through

a low-pass filter.

AREF:- AREF is the analog reference pin for the A/D Converter.These pins

are powered from the analog supply and serve as 10-bit ADC channels.

Basic Function:- The main function of the CPU core is to ensure correct

program execution. The CPU must therefore be able to access memories,

perform calculations, control peripherals, and handle interrupts.

18

Interfacing Of Data Bus With Different Units

19

In order to maximize performance and parallelism, the AVR uses a Harvard

architecture with separate memories and buses for program and data.

Instructions in the Program memory are executed with a single level

pipelining. While one instruction is being executed, the next instruction is

pre-fetched from the Program memory. This concept enables instructions to

be executed in every clock cycle.

The Program memory is In-System Reprogrammable Flash memory.The

fast-access Register File contains 32 x 8-bit general purpose working

registers with a single clock cycle access time. This allows single-cycle

Arithmetic Logic Unit (ALU) operation. In a typical ALU operation, two

operands are output from the Register File, the operation is executed, and the

result is stored back in the Register File in one clock cycle.

Six of the 32 registers can be used as three 16-bit indirect address register

pointers for Data Space addressing enabling efficient address calculations.

One of the these address pointers can also be used as an address pointer for

look up tables in Flash Program memory. These added function registers are

the 16-bit X, Y and Z-register.The ALU supports arithmetic and logic

operations between registers or between a constant and a register. Single

register operations can also be executed in the ALU.After an arithmetic

operation, the Status Register is updated to reflect information about the

result of the operation.The Program flow is provided by conditional and

unconditional jump and call instructions, able to directly address the whole

address space. Most AVR instructions have a single 16-bit word format.

Every Program memory address contains a 16- or 32-bit instruction.

20

Program Flash memory space is divided in two sections, the Boot program

section and the Application program section. Both sections have dedicated

Lock Bits for write and read/write protection. The SPM instruction that

writes into the Application Flash memory section must reside in the Boot

program section.During interrupts and subroutine calls, the return address

Program Counter (PC) is stored on the Stack. The Stack is effectively

allocated in the general data SRAM, and consequently the Stack size is only

limited by the total SRAM size and the usage of the SRAM. All user

programs must initialize the SP in the reset routine (before subroutines or

interrupts are executed). The Stack Pointer SP is read/write accessible in the

I/O space.The data SRAM can easily be accessed through the five different

addressing modes supported in the AVR architecture.The memory spaces in

the AVR architecture are all linear and regular memory maps.

A flexible interrupt module has its control registers in the I/O space

with an additional global interrupt enable bit in the Status Register. All

interrupts have a separate Interrupt Vector in the Interrupt Vector table. The

interrupts have priority in accordance with their Interrupt Vector position.

The lower the Interrupt Vector address, the higher the priority.The I/O

memory space contains 64 addresses for CPU peripheral functions as

Control Registers, SPI, and other I/O functions. The I/O Memory can be

accessed directly, or as the Data Space locations following those of the

Register File, 0x20 - 0x5F.

21

TRANSISTOR

The transistor’s function is to amplify an electric current. Many different

kinds of transistors are used in analog circuits, for different reasons. This is

not the case of digital circuits. In a digital circuit, only two values matters,

on and off. The amplification ability of transistor is not relevant in digital

circuit. In many cases, a circuit is built with integrated circuits (ICs).

Transistors are often used in digital circuits as buffer to protect ICs. For

example, when powering an electromagnetic switch (called a ‘relay’), or

when controlling a light emitting diode (In any case).

Two different symbol are used for the transistor.

PNP Type

22

NPN Type

The name (standard part number) of the transistor, as well as the type and

the way it is used is shown below.

2SAXXXX PNP type high frequency

2SBXXXX PNP type low frequency

2SCXXXX NPN type high frequency

2SDXXXX NPN type low frequency

The direction of the current flow differs between the NPN and PNP type.

When the power supply is the side of positive (plus), the NPN type is easy to

use.

TRANSRECEIVER

Here we are using zigbee transreceiver for wireles communication.

ZigBee is the specification of a low-cost, low-power wireless

communications solution, meant to be integrated as the main building block

of ubiquitous networks. It is maintained by the ZigBee Alliance, which

develops the specification and certifies its proper implementation. ZigBee

builds upon the physical layer and medium access control defined in IEEE

standard 802.15.4 for low-rate WPAN's. The specification goes on to

complete the standard by adding four main components: network layer,

23

application layer, ZigBee device objects (ZDO's) and manufacturer-defined

application objects which allow for customization and favor total

integration. These are responsible for a number of tasks, which include

keeping of device roles, management of requests to join a network, device

discovery and security. Its network layer natively supports three types of

topologies: both star and tree typical networks and generic mesh networks.

Every network must have one coordinator device, tasked with its creation,

the control of its parameters and basic maintenance. Within star networks,

the coordinator must be the central node.

The main functions of the network layer are to enable the correct use of the

MAC sublayer and provide a suitable interface for use by the next upper

layer, namely the application layer. The routing protocol used by the

Network layer is AODV. In order to find the destination device, it

broadcasts out a route request to all of its neighbors. The neighbors then

broadcast the request to their neighbors, etc until the destination is reached.

Once the destination is reached, it sends its route reply via unicast

transmission following the lowest cost path back to the source.

Once the source receives the reply, it will update its routing table for the

destination address with the next hop in the path and the path cost.

The application layer is the highest-level layer defined by the specification,

and is the effective interface of the ZigBee system to its end users. It

comprises the majority of components added by the ZigBee specification:

both ZDO and its management procedures, together with application objects

defined by the manufacturer, are considered part of this layer.

24

Zigbee protocol stack

As one of its defining features, ZigBee provides facilities for carrying out

secure communications, protecting establishment and transport of

cryptographic keys, cyphering frames and controlling devices. It builds on

the basic security framework defined in IEEE 802.15.4. This part of the

architecture relies on the correct management of symmetric keys and the

correct implementation of methods and security policies.

25

LIGHT EMITTING DIODE (LED)

Light emitting diode must be chosen according to how they will be used,

because there are various kinds. The led are available in several colours. The

most common colours are red and green, but there are even blue ones.

The device on the far right in the photograph combines a red LED and green

LED in one package. The component lead in the middle is common to both

LED’s as for the remaining two leads; one side is for green, the other for the

red LED. When both are tuned ON simultaneously, it becomes orange.

When an LED is new out of package, the polarity of the device can be

determined by looking at the leads. The longer leads are the anode sides, and

the shortest one is the cathode side. The polarity of an LED can also be

determined using a resistor meter or even a 1.5 V battery.

26

When using a test meter to determine polarity, set the meter to a low

resistance measurement range. Connect the probe of the meter to the LED. If

the polarity is correct, the LED will glow. If the LED does not glow, switch

the meter probes to the opposite leads on the LED.

CAPACITORS

A capacitor can store charge and its capacity to store charge is called

capacitance. Capacitors consists of two conducting plates, separated by an

insulating material (known as dielectric). The two plates are joined with two

leads. The dielectric could be air, mica , paper ceramic, polyester,

polystyrene etc. The dielectric gives name to the capacitor. Like paper

capacitor, mica capacitor etc.

Types of capacitors :

27

Capacitor can be broadly classified in two categories, i.e., Electrolytic

capacitor and Non-Electrolytic capacitor as shown in the figure above.

Electrolytic Capacitor:

Electrolytic capacitors have an electrolyte as a dielectric. When such an

electrolyte is charged, chemical changes take place in the electrolyte. If it’s

one plate is charged positively, same plate must be charged positively in the

future. We call such capacitor as polarized. Normally we see electrolytic

capacitor as polarized capacitor and the leads are marked with positive or

negative on the can. Non-electrolytic capacitors have dielectric material such

28

as paper, mica or ceramic. Therefore, depending upon the dielectric, these

capacitor are classified.

Mica Capacitor:

It is sandwich of several thin metal plates separated by thin sheet of mica.

Alternate plates are connected together and leads attached for outside

connections. The total assembly is encased in a plastic capsule or Bakelite

case. Such capacitor have small capacitance value (50 to 500pf) and high

working voltage (500V and above). The mica capacitors have excellent

characteristics under stress of temperature variation and high voltage

application. These capacitor are now replaced by ceramic capacitor.

Ceramic Capacitor:

Such capacitor have disc or hollow tabular shaped dielectric made of

ceramic material such as titanium dioxide and barium titanic. Thin coating

of silver compound is deposited on both sides of dielectric disc, which acts

as capacitor plates. Leads are attached to each sides of the dielectric disc and

whole unit is encapsulated in a moisture proof coating. Disc type capacitors

have very high value up to 0.001uf. Their working voltage range from 3V to

60000V. These capacitor have very low leakage current. Breakdown voltage

is very high.

THE DIODE:

29

Diode are polarized, which means that they must be inserted into the PCB

the correct way round. This is because an electric current will only flow

through them in one direction (like air will only flow one way through a tyre

valve). Diode have two connections, an anode and a cathode. The cathode is

always identified by a dot, ring or some other mark.

The PCB is often marked with a +sign for the cathode end. Diodes come in

all shapes and sizes. They are often marked with a type number. Detailed

characteristics of a diode can be found by looking up the type number in a

data book. If you know how to measure resistance with a meter then test

some diodes. A good one has low resistance in one direction and high in

other. They are specialized type of diode available such as the zener and

light emitting diode (LED).

30

CHARACTERSTICS OF DIODES:

When a small voltage is applied to the diode in the forward direction, current

flows easily. Because the diode has a certain amount of resistance, the

voltage will drop slightly as current flow through the diode. A typical diode

causes a voltage drop about 0.6-1V (VF) (In the case of silicon diode almost

0.6V). This voltage drop needs to be taken into consideration in a circuit

which uses many diodes in series. Also, the amount of current passing

through the diodes must be considered.

When voltage is applied in the reverse direction through a diode, the diode

will have a great resistance to current flow. Different diodes have different

characteristics when reverse-biased. A given diode should be selected

depending on how it will be used in the circuit.

31

The current that will flow through a diode biased in the reverse direction will

vary from several mA to just µA, which is very small.

Voltage regulation diode (Zener Diode):

The circuit symbol is

It is used to regulate voltage, by taking advantage of the fact that Zener

Diodes tend to stabilize at a certain voltage when that voltage is applied in

the opposite direction.

Light emitting diode:

The circuit symbol is

This type of Diode emits light when current flows through it in the forward

direction (Forward biased).

Variable capacitance diode :

The circuit symbol is

32

The current does not flow when applying the voltage of the opposite

direction to the diode. In this condition, the diode has a capacitance like the

capacitor. It is a very small capacitance. The capacitance of the diode

changes when changing voltage. With the change of this capacitance, the

frequency of the oscillator can be changed.

RESISTORS:

The flow of charge (or current) through any material, encounter an opposing

force similar in many respect to mechanical friction. This opposing force is

called resistance of the material. It is measured in ohms. In some electric

circuits resistance is deliberetly introduced in the form of resistor.

Resistors are of following types:

1. Wire wound resistors.

2. Carbon resistors.

3. Metal film resistors.

Wire Wound Resistors:

Wire wound resistors are made from a long (usually Ni-Chromium) wound

on a ceramic core. Longer the length of the wire, higher is the resistance. So

depending on the value of resistor required in a circuit, the wire is cut and

wound in a ceramic core. This entire assembly is coated with a ceramic

metal. Such resistors are available in power of 2 watts to several hundred

33

watts and resistance value from 1 Ohm to 100K Ohms. Thus wire wound

resistors are used for high currents.

Carbon Resistor:

Carbon resistors are divided into three types:

a.

Carbon composition resistors are made by mixing carbon grains with

binding material (glue) and module in the forms of rods. Wire leads are

inserted at the two ends. After this an insulating material seals the resistor.

Resistor are available in power rating of 1/10, 1/8, 1/4, 1/2, watts and value

from 1 ohm to 20 ohms.

b.

Carbon film resistors are made by deposition carbon film on a ceramic rod.

They are cheaper than carbon composition resistors.

c.

Cement film resistors are made of thin carbon coating fired onto a solid

ceramic substrate. The main purpose is to have more precise resistance

values and greater stability with heat. They are made in a small square with

leads.

Metal Film Resistor:

They are also called thin film resistors. They are made of thin metal coating

deposited on a cylindrical insulating support. The high resistance values are

34

not precise in value; however, such resistors are free of induction effect that

is common in wire wound resistors at high frequency.

Variable resistors:

Potentiometer is a resistor where value can be set depending on the

requirement. Potentiometer is widely used in electronic systems. Examples

are volume control, tons control, brightness and contrast control of radio or

T.V. sets.

Fusible Resistors:

These resistors are wire wound type and are used in T.V. circuits for

protection. They have resistance of less than 15 ohms. Their function is

similar to a fuse made flow off whenever current in the circuit exceeds the

limit.

MOTORS:

Motor is an electromechanical device or digital motor as it can move in

discrete steps and traverse through 360 degrees. Now a days many computer

peripherals contain one or more motors.

35

The two main characteristics of motors are synchronism and constant step

size. The brushed DC electric motor generates torque directly from DC

power supplied to the motor by using internal commutation, stationary

permanent magnets, and rotating electrical magnets. Like all electric motors

or generators, torque is produced by the principle of Lorentz force, which

states that any current-carrying conductor placed within an external

magnetic field experiences a torque or force known as Lorentz force.

Advantages of a brushed DC motor include low initial cost, high reliability,

and simple control of motor speed. Disadvantages are high maintenance and

low life-span for high intensity uses. Maintenance involves regularly

replacing the brushes and springs which carry the electric current, as well as

cleaning or replacing the commutator. These components are necessary for

transferring electrical power from outside the motor to the spinning wire

windings of the rotor inside the motor.

LCD:

A liquid crystal display (LCD) is a thin, flat electronic visual display that

uses the light modulating properties of liquid crystals(LCs). LCs do not emit

light directly.it is an electronically-modulated optical device made up of any

number of pixels filled with liquid crystals and arrayed in front of alight

source (backlight) or reflector to produce images in colour or monochrome.

Each pixel of an LCD typically consists of a layer of molecules aligned

between two transparent electrodes, and two polarizing filters, the axes of

36

transmission of which are (in most of the cases) perpendicular to each other.

With no actual liquid crystal between the polarizing filters, light passing

through the first filter would be blocked by the second (crossed) polarizer. In

most of the cases the liquid crystal has double refraction.

Before applying an electric field, the orientation of the liquid crystal

molecules is determined by the alignment at the surfaces of electrodes.

Table of Pin Description of LCD :

MAX-232:

37

The MAX232 is an integrated circuit that converts signals from an RS-

232 serial port to signals suitable for use in TTL compatible digital logic

circuits. The MAX232 is a dual driver/receiver and typically converts the

RX, TX, CTS and RTS signals.

The drivers provide RS-232 voltage level outputs from a single + 5 V

supply via on-chip charge pumps and external capacitors. This makes it

useful for implementing RS-232 in devices that otherwise do not need any

voltages outside the 0 V to + 5 V range, as power supply design does not

need to be made more complicated just for driving the RS-232 in this case.

When a MAX232 IC receives a TTL level to convert, it changes a TTL

Logic 0 to between +3 and +15 V, and changes TTL Logic 1 to between -3

to -15 V, and vice versa for converting from RS232 to TTL.

The MAX232 is a dual driver/receiver that includes a capacitive voltage

generator to supply EIA-232 voltage levels from a single 5-V supply.

RS232 Line Type & Logic Level

RS232 Voltage

TTL Voltage to/from MAX232

38

Data Transmission (Rx/Tx) Logic 0

+3 V to +15 V 0 V

Data Transmission (Rx/Tx) Logic 1

-3 V to -15 V 5 V

Max-232(operating circuit)

39

40

IC 7805 :

Three terminal positive fixed voltage regulators:

These voltage regulators are monolithic integrated circuits designed as fixed

voltage. These regulators employ internal current limiting, thermal

shutdown, and safe area compensation. With adequate heat sinking they can

deliver output current in excess of 1.0A. Although designed primarily as

fixed voltage regulator, these devices can be used with external component

to obtain adjustable voltages and currents.

41

WORKING:

The two blocks represent the two trains having Anti-Collision System.

ACD (ANTICOLLISION DEVICE) consists of a microcontroller,LCD panel and Wireless Communication Unit,Potentiometer,button switches,transistor,LED etc.

If the two trains are on same track,heading towards each other and if it comes in the range of transreceiver then the red LED will glow and a warning message is displayed on the LCD panel and both the trains will automatically stop.

If the two trains are on same track moving in the same direction then ACD will check for speed and if the speed of rear end train is more then the rear end train will automatically stop without affecting the front end train .

The rear end train will not move until any of the train changes the track.

As ACD will detect the collision, the red LED will glow and a warning message is displayed on the LCD panel.

The green LED indicates the smooth movement of trains.

42

BIBILOGRAPHY AND REFRENCE

Through Books and Magzine

1. INTEGERATED ELECTRONICS (TMH edition 1991) By Jacob Millman

& Christos C. Halkias

2. Kenneth J. Ayala “The 8051 Microcontroller – Architecture,

Programming and application”.

3. James W. Stewart “The 8051 Microcontroller – Hardware, Software

and Interfacing (Pearson).

4. Raj Kamal “Microcontrollers: Architecture, Programming,

Interfacing and System Design” Pearson edition 2005

5. Muhammad Ali Mazidi, Janice Gillispie Mazidi and Rolin D. McKinlay

The 8051 Microcontroller and Embedded Systems ( PHI of India Ltd.,

New Delhi 2nd Edition 2006.

Through Internet :

1. www.datasheet.com

2. www.electronicsforyou.com

43

3. www.coolcircuit.com

4. www.williamsonlabs.com

5. www.wikipedia.com

6. www.fairchildsemi.com

7. www.datasheetcatalog.com

44