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.