1. Arduino Motor Lab Inspired by NYU ITP project
CTY SAR FCPS
Shawn Lupoli, Elliot Tan

2. Let’s understand what we are working with…

3. How to change a Motor’s Directions?
Working with a DC motor, which is a high-current DC load
Can reverse the direction of the current in the motor using an H-bridge
H-bridge is a circuit that enables voltage to be applied in either direction

4. Visual of the H-Bridge

5. Get the motor running, then turn the motor’s direction with a switch
Goal
Get the motor running, then turn the motor’s direction with a switch

6. Programming the Motor Turn

7. Motor Part 1 Initializing global variables Setup()
Need a switch input, H-bridge leg1 (pin 2, 1A), H-bridge leg2 (pin7, 2A), and an H-bridge enable pin
“const int switchPin = 2” , “const int motor1Pin = 3” , “const int motor2Pin = 4” , “const int enablePin = 9”
Setup()
pinMode(pin, mode) – configures the specified pin to behave either as an input or an output
digitalWrite(pin, value) – write a HIGH or LOW value to a digital pin

8. Motor Part 2 Loop() Functions Things to consider digitalWrite()
What happens when “digitalRead(switchPin) == High” ?
What happens if this is not true?

9. CODE

10. Building the Motor circuit

11. Supplies 1 Arduino Leonardo board 1 breadboard
7 short wires (2 red, 5 black)
6 medium wires (3 brown, 2 red, 1 black)
2 long wires (1 red, 1 black)
1 H-Bridge
1 switch
1 9V battery
1 resistor (1 kΩ)
1 motor
* Notes:
Wires are 22 or 24 AWG, solid
Short wires = 5 cm
Medium wires = 12 cm
Long wires = 16 cm

12. Diagram of Motor Circuit

13. Connecting Code and Circuit

14. Putting it All Together
UPLOAD!
Remember to check for the flashing RX and TX lights, and a “Successful upload” message in your console
Understanding the process
First, set up constants for the switch pin, the two H-bridge pins, and the enable pin of the H-bridge
Second, set all pins for the H-bridge as outputs, and the pin for the switch as input
Third, turn the motor on by setting the enable pin high so the H-bridge turns the motor on
Fourth, read the switch in loop(). If input = “high”, turn the motor one way by making one H-bridge pin high and the other low. If input = “low” reverse the states of the two H-bridge pins.

15. Troubleshooting Make sure the H-bridge is in the right place!
Check connection of wires between battery and circuit board!
Questions?