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fawaz_final_viva.zipWhite Line Follower.pptx
White Line Follower
By
Fawaz Alanazi
Fawaz
motor control
Motor Control
The H bridge was chosen as a method of controlling the motors as it supplies efficient control over forwards and backwards on each motor.
The image shows a basic diagram of a h bridges when all the switches are open there is no current going through the H bridge and the motor does not move.
The diagram above shows the 4 switching elements namely low side left, low side right, high side left and high side right. The motor changes its direction according to the element that is switched on. For example, if the switch of high side left and low side right is turned on then the motor will rotate forward as with the flow of the current to the ground through motor coil.
the h-bridge is preferred for interfacing DC motor with the microcontroller for the control of direction of the rotation and speed of the motor. H-bridge the name is derived from the real shape of the circuit of the motor. The h-bridge has 4 switching elements which are shown.
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H -BRIDGE
It is an electronic circuit which enable voltage to be applied across a load in either direction.
It allows a circuit full control over standard electronic DC motor. That is with an H- bridge , logic chip
H- bridges are available as integrate circuits.
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How the motor operates
The red line shows the current path if the top right and the bottom left switches are closed. This will send the motor spinning in one direction for example forward. If the opposite switches were to be closed then the motor would go into reverse.
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table for direction
| H BRIDGE INPUT PIN | ||||
| Direction | 1 | 2 | 3 | 4 |
| FWD | 1 | 0 | 0 | 1 |
| REV | 0 | 1 | 1 | 0 |
| LEFT | 1 | 0 | 0 | 0 |
| RIGHT | 0 | 0 | 0 | 1 |
H-bridge driver IC L293D
The outputs in L293D are motors which consist of 2 inputs and 2 outputs each. Motor 1 has the input 1 and 2 and motor 2 has the inputs 3 and 4. Likewise, the motor 1 has outputs 1 and 2 and motor 2 has outputs 3 and 4. Logic 1 and enable 1 will enable the inputs 1 and 2 and outputs 1 and 2 which means motor 1. Furthermore, enable 2 will enable inputs and outputs 3 and 4 which are motor 2.
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L293D
It is a dual H-bridge motor driver.
Can control two motors.
16 pins.
Out put current of 600 mA and peak output current 1.2 per channel.
Power supply can be as large as 36 volts.
for protection of circuit from back EMF output diodes are included within the L293D.
Circuit Connections
Pin 1 and 9 are the 2 enable pins in which pin 1 enables motor 1 and pin 9 enables motor 2. The L293D has four output pins connected to its input terminals and various logics can be provided to control the motor’s direction. The motor 1 would be connected across output 1 and 2 which are pin 3 and 6 while the motor 2 would be connected across output 3 and 4 which are pins 11 and 14. Pins 4, 5, 12 and 13 are connected to the ground while pins 16 and 8 are connected to VCC=5V.
The diagram below shows the L293D’s circuit connections.
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Questions
