This document describes an anti-collision system for unmanned railway crossings that uses GPS receivers in trains to track locations and prevent collisions. When trains get within a minimum distance, both will stop. Infrared sensors activate gate controls when a train reaches a specific spot. Train locations are sent via GSM modem to a server and displayed to alert drivers. The system uses a microcontroller, sensors, transmitters, receivers and other hardware to monitor trains and control gates for increased safety.

2. INTRODUCTION
Embedded System is a combination of
hardware and software used to achieve a single
task. It is a computer system that monitor
respond to, or control an external environment.
Environment are connected to systems through
sensors, actuators and other I/O interfaces.
Embedded system must meet timing and other
constraints imposed on it by environment

3. 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.

7. 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

8. PIN DIAGRAM

9. 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

10. OBSTACLE SENSOR
Modulated IR transmitter
Ambient light protected IR receiver
3 pin easy interface connectors
Indicator LED
Up to 12 inch range for white object
Can differentiate between dark and light colours

11. 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.

12. RELAY DIAGRAM

13. 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.

14. PIN DIAGRAM RF & TF

15. 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

16. GSM MODEM
It is a specialized type of modem which accepts a SIM
card
operates over a subscription to a mobile operator
It is used for sending and receiving SMS and MMS
messages.
From the mobile operator perspective, a GSM modem
looks just like a mobile phone.

17. IR LED
An IR LED, also known as IR transmitter
It 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

18. PIN DIAGRAM OF IR LED

19. 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

21. DECODER
18 PIN DIP
8 ~ 12 Address Pins and 0 ~ 4 Data Pins
Easy Interface with an RF of IR
transmission medium
Minimal External Components
Capable of Decoding 12 bits of Information

23. ANTI COLLISION DEVICE
The Anti Collision Device is a form of Automatic
train protection
ACDs have knowledge embedded intelligence
They take inputs from GPS satellite system for
position updates
It act as a watchdog in the dark as they constantly
remain in lookout for other train bound ACDs

24. 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

25. SENDING THE MESSAGE
To send the SMS message, type the following
command:
AT+CMGS="+31638740161" <ENTER>

26. 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>

27. 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>

28. SCOPE FOR ADVANCEMENT
Train information is transmitted
to next station and road traffic

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

30. ADVANTAGES
Pre information of train arrival.
System placed within locomotive of the
train.
Accident avoidance.
Safety and quality of service.

31. DISADVANTAGES
Cost is high.
cannot work at power failure.