dcmotorexample.ino

#define enA 9
#define in1 6
#define in2 7
#define button 4
int rotDirection = 0;
int pressed = false;
void setup() {
  pinMode(enA, OUTPUT);
  pinMode(in1, OUTPUT);
  pinMode(in2, OUTPUT);
  pinMode(button, INPUT);
  digitalWrite(in1, LOW);
  digitalWrite(in2, HIGH);
}
void loop() {
  int potValue = analogRead(A0);
  int pwmOutput = map(potValue, 0, 1023, 0 , 255);
  analogWrite(enA, pwmOutput);
  if (digitalRead(button) == true) {
    pressed = !pressed;
  }
  while (digitalRead(button) == true);
  delay(20);
  if (pressed == true  & rotDirection == 0) {
    digitalWrite(in1, HIGH);
    digitalWrite(in2, LOW);
    rotDirection = 1;
    delay(20);
  }
  if (pressed == false & rotDirection == 1) {
    digitalWrite(in1, LOW);
    digitalWrite(in2, HIGH);
    rotDirection = 0;
    delay(20);
  }
}