INTRODUCTIONEmbedded System is a combination ofhardware and software used to achieve a singletask. It is a computer system that monitorrespond to, or control an external environment.Environment are connected to systems throughsensors, actuators and other I/O interfaces.Embedded system must meet timing and otherconstraints imposed on it by environment

SYNOPSIS

The project aims at designing Anti-Collision System and controlling unmanned Railway crossings. The anti-collision system is implemented by fitting GPS receiver in each train. Each train will compare the GPS co-ordinates sent by the neighboring trains with its own GPS co-ordinate system. When the difference between the trains coming in same GPS co-ordinate reaches minimum level, then both trains will stop. When the train reaches the spot where the IR sensors are placed the close command for gate control system is activated. The received location will send form the server in the form of GSM modem and the server will response the position of the train. The information will be send from the main server with the location of the train. The control of unmanned railway crossing is implemented by placing display as well as alarm indicator in the train so that they can find the each train location in the same track about few kilometers before the crossing area.

MICROCONTROLLER The AT89C51 is a low-power, high-

performance CMOS 8-bit microcomputer It has 4Kbytes of Flash programmable

and erasable read only memory (PEROM).

AT89C51 is a powerful microcomputer which providesa highly-flexible and cost-effective

PIN DIAGRAM

FEATURES • 128 x 8-bit Internal RAM • 32 Programmable I/O Lines • Two 16-bit Timer/Counters • Six Interrupt Sources • Programmable Serial Channel • Low-power Idle and Power-down

Modes • Fully Static Operation: 0 Hz to 24

MHz

OBSTACLE SENSORModulated IR transmitterAmbient light protected IR receiver3 pin easy interface connectorsIndicator LEDUp to 12 inch range for white objectCan differentiate between dark and light

colours

RELAY

A relay is an electrical switch that opens and closes

By the control of another electrical circuit it works.

The switch is operated by an electromagnet to open or close one or many sets of contacts.

It can able to control an output circuit of higher power than the input circuit.

RELAY DIAGRAM

RF TRANSMITTER &RECEIVER The transmitter/receiver (Tx/Rx) pair operates at a

frequency of 434 MHz

An RF transmitter receives serial data and transmits it wirelessly through RF through its antenna

The transmission occurs at the rate of 1Kbps - 10Kbps

The transmitted data is received by an RF receiver operating at the same frequency as that of the transmitter.

PIN DIAGRAM RF & TF

RS 232 Highly Reliable for 24x7 operation

with SMPS power supply adapter / Matched Antenna

Status of Modem Indicated by LED

Simple to Use & Low Cost

Quad Band Modem supports all GSM operator SIM cards

GSM MODEMIt is a specialized type of modem which

accepts a SIM cardoperates over a subscription to a mobile

operatorIt is used for sending and receiving SMS and

MMS messages.From the mobile operator perspective, a GSM

modem looks just like a mobile phone.

IR LEDAn IR LED, also known as IR transmitterIt is a special purpose LED that transmits

infrared rays in the range of 760 nm wavelength.

It is made of gallium arsenide or aluminium gallium arsenide

IR receivers, are commonly used as sensors

PIN DIAGRAM OF IR LED

ENCODER 18 PIN DIP Operating Voltage : 2.4V ~ 12V Low Power and High Noice

Immunity CMOS Technology Low Standby Current and Minimum

Transmission Word Built-in Oscillator needs only 5%

Resistor Easy Interface with and RF or an

Infrared transmission medium

DECODER

18 PIN DIP8 ~ 12 Address Pins and 0 ~ 4 Data

PinsEasy Interface with an RF of IR

transmission mediumMinimal External ComponentsCapable of Decoding 12 bits of

Information

ANTI COLLISION DEVICE

The Anti Collision Device is a form of Automatic train protection

ACDs have knowledge embedded intelligenceThey take inputs from GPS satellite system

for position updatesIt act as a watchdog in the dark as they

constantly remain in lookout for other train bound ACDs

SEND SMS USING AT COMMANDS

Some advanced GSM modems like WaveCom and Multitech, support the SMS text mode

This mode allows you to send SMS messages using AT commands, without the need to encode the binary PDU field of the SMS first.

This is done by the GSM modem

SENDING THE MESSAGE

To send the SMS message, type the following command:

AT+CMGS="+31638740161" <ENTER>

SETTING UP THE MODEM

If the modem contains a SIM card with is secured with a PIN code, we have to enter this pin code first:

AT+CPIN="0000" <ENTER> 

CHECK YOUR GSM MODEM SUPPORT SMS TEXT MODE

To check if your modem supports this text mode, you can try the following command:

AT+CMGF=1 <ENTER>

SCOPE FOR ADVANCEMENT

Train information is transmitted to next station and road traffic

USES

Used on unmanned railway crossing.Advanced train arrival information.Time duration setting.

ADVANTAGES

Pre information of train arrival.System placed within locomotive of

the train.Accident avoidance.Safety and quality of service.

DISADVANTAGES

Cost is high.cannot work at power failure.