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.
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Embedded System Controls Unmanned Railway Crossings
1.
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.
4.
5.
6.
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
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.
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.
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
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
20.
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
22.
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>