H-Bridge Motor Driver

Applications The H-Bridge is used to control larger amounts of power The H-Bridge is also used to change the direction of current flow

Motor Application A motor’s direction is determined by the direction of current flow An H-Bridge allows us to change polarity without physically unplugging and switching the motor wires

Motor Application A wheelchair motor requires: 24 volts, 4 amps (24x4 = 96 watts) The Arduino digital pins provide: 5 Volts, .04 amps (5 x .04 = 0.2 watts) That’s 4,800 digital Arduino pins!

Motor Application A larger power source is needed to drive the motor We just want the Arduino to control the flow For this we can use a H-Bridge motor driver!

How it Works The H-Bridge consists of 4 transistors in an “H” configuration Transistors are switches that the Arduino can open and close

How it Works Closing switches S1 and S4 forces the electricity to flow left to right ‘Close’ a switch by connecting it to a HIGH Arduino pin 2 Arduino pins are needed (S1 + S4 and S2 + S3)

How it Works Closing switches S2 and S3 forces the electricity to flow right to left The power being used to operate the H-Bride is DIFFERENT than that being used to power the motor

How it Works

Wiring The Vcc pin is for supply that will power the motors The green terminals are for 2 motors The 4 male pins go to Arduino digital pins. Two per motor

Wiring We require a separate 5v source to power the transistor The button to the right allows the chip to “steal” power from the larger VCC motor supply In this case the +5v is not needed

Wiring All motor drivers have similar pins, although their location on the board might differ

Complete the H-Bridge lab in Unit 12