Download H-Bridge

H-Bridge Motor Driver
1
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
2
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
3
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!
4
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!
5
How it Works
• The H-Bridge consists
of 4 transistors in an
“H” configuration
• Transistors are
switches that the
Arduino can open and
close
6
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)
7
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
8
How it Works
9
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
10
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
11
Wiring
• All motor drivers have
similar pins, although
their location on the
board might differ
12
LAB
Complete the H-Bridge lab in
Unit 12
13