Load up the following sketch onto your Arduino.
/*
Adafruit Arduino - Lesson 15. Bi-directional Motor
*/
int enablePin = 11;
int in1Pin = 10;
int in2Pin = 9;
int switchPin = 7;
int potPin = 0;
void setup()
{
pinMode(in1Pin, OUTPUT);
pinMode(in2Pin, OUTPUT);
pinMode(enablePin, OUTPUT);
pinMode(switchPin, INPUT_PULLUP);
}
void loop()
{
int speed = analogRead(potPin) / 4;
boolean reverse = digitalRead(switchPin);
setMotor(speed, reverse);
}
void setMotor(int speed, boolean reverse)
{
analogWrite(enablePin, speed);
digitalWrite(in1Pin, ! reverse);
digitalWrite(in2Pin, reverse);
}
Pins are defined and their modes set in the 'setup' function as normal.
In the loop function, a value for the motor speed is found by dividing the analog reading from the pot by 4.
The factor is 4 because the analog reading will be between 0 and 1023 and the analog output needs to be between 0 and 255.
If the button is pressed, the motor will run in forward, otherwise it will run in reverse. The value of the 'reverse' variable is just set to the value read from the switch pin. So, if the button is pressed, this will be False, otherwise it will be True.
The speed and reverse values are passed to a function called 'setMotor' that will set the appropriate pins on the driver chip to control the motor.
