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SUBMITTED BY LENIN C
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WELCOME
AUTOMATIC LEVEL CROSSING
SUBMITTED BY LENIN C
INTRODUCTION
• Railways - cheapest mode of transportation .• Aims to avoid accidents. • Using simple electronic components- automate the control of
railway gates.
• Indicator light - alert the motorists about approaching train.
BLOCK DIAGRAM
PIC 16F877A
MICROCONTROLLER
POWER SUPPLY UNIT
TRANSMITTER RECEIVER
UNIT
GATE CONTROL UNIT
BLOCK DIAGRAM DESCRIPTION
1.POWER SUPPLY UNIT
• Consists of transformer, Bridge rectifier & regulator.• Power supply -230V ac single phase .• Output - rectifier circuit.• Regulator 7805 provide 5V –microcontroller operation.
2. TRANSMITTER RECEIVER UNIT
2 powerful IR transmitters and two receivers.IR LED Fixed at 2 KM.Sensor along the train direction -‘foreside sensor’ , other - ‘aft side sensor’.
3.GATE CONTROL UNIT
Consists of motor driver, H Bridge and DC motor.Major components used - PIC microcontroller 16F877A, ULN
2803 and 30 rpm geared DC motor.DC motor controls gate opening and closing.Driver IC 2803 decodes the coding - conveys necessary data to
DC motor.
START
GATE OPENS, GREEN SIGNAL FOR ROAD USERS
IF TRAIN REACHES SENSOR1
GATE CLOSES, BUZZER SOUNDS RED SIGNAL FOR ROAD USERS
YES
NO
IF TRAIN REACHES SENSOR2
GATE OPENS, BUZZER STOPS, GREEN LIGHT FOR ROAD USERS
STOP
FLOWCHART
YES
NO
SCHEMATIC DIAGRAM FOR GATE CONTROL UNIT
CIRCUIT DIAGRAM
CIRCUIT DIAGRAM DESCRIPTION
1.POWER SUPPLY UNIT
Step down transformer-reduce high voltage. Rectifier -ac to dc . Regulator -regulates output , avoid fluctuations.
Input filter -remove harmonics and ripples.Output filter –remove ripples in output.
2. IR TRANSMITTER
•IR LED series with resistor. •IR LED- detection. •IR led - constantly emits light.•Power consuming.•Optimized for low ranges.
3. IR RECEIVER
Detects transmitted IR pulses . • Train crosses sensor, output transits
to low state. • IR light falls , emitter to collector
voltage increases. • More light intensity - more voltage
drop. • As voltage drop increases- output of
op-amp high.
4.PIC MICROCONTROLLER
• PIC 16F877A- 40 pin IC• Crystal oscillator- 16 MHz• Input pins - RA0 & RA1• Output - port B pins• RA0 low – outputs 0 1 0 1 sequence – rotate motor
clockwise.• RA1 low – RA1 high – outputs 1 0 1 0 sequence – rotate
motor anticlockwise.
PIC DESCRIPTION
5. DC MOTOR
•30 RPM geared DC motor. •Simple electromagnetism.•DC motor – clockwise direction – gate closes.•DC motor – anticlockwise direction – gate opens.•Forward and reverse operation - changing the direction of current.
6.ULN - 2803
•Motor driver IC.•No VCC pin.•Decodes coding - conveys data to DC motor•Port B drives DC motor through ULN2803.•PIC outputs 0 1 0 1- ULN outputs 1 0 1 0 - one terminal of DC motor to VCC- other terminal to gnd -DC motor rotates clockwise and viceversa.
OPERATION
Two pairs of IR sensors .Gate operated by DC motor.DC motor interfaced to ULN2803. Train arrives sensor1- DC motor rotates forward – gate closes-
red signal glow-buzzer beeps. Train reaches sensor2- DCmotor rotates reverse- gate opens -
green signal glow-buzzer stops.
START
INITIALIZE RA0 & RA1
RED LIGHT GLOWS, BUZZER STARTS, GATE CLOSED
IF RA0=
0
IF RA1=
0
GREEN LIGHT GLOWS, BUZZER STOPS , GATE OPENS
IF RA1=1
STOP
1
1
PROGRAM FLOWCHART
YES
YES YES
NO
NO
NO
ADVANTAGES
Accidents are avoided.High accuracy.No time lag.
DISADVANTAGES
Regular assessment of safety performance.Motor requires 223v ac power supply. REMEDY: Using solar cell batteries.
SCOPE OF PROJECT
Better working of INDIAN RAILWAY. User friendly. Can be expanded according to demand. Additional modules can be added .
CONCLUSION
Improving safety level crossings. Priority of safety enhancement .
REFERENCES
SITESwww.scribd.comwww.google.com
THANK YOU