1. H-Bridge Motor Driver

2. 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

3. 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

4. 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!

5. 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!

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

7. 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)

8. 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

9. How it Works

10. 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

11. 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

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

13. Complete the H-Bridge lab in
Unit 12