Arduino sketch for unipolar stepper motors (to be used with uln2803)

gistfile1.ino

int motorPins[] = {11, 10, 9, 8};
int count = 0;
int count2 = 0;
int delayTime = 500;
int val = 0;
int ledPin = 13;

void setup() {
  Serial.begin(9600);
  pinMode(ledPin, OUTPUT);
  for (count = 0; count < 4; count++) {
    pinMode(motorPins[count], OUTPUT);
  }
}

void moveForward() {
  if ((count2 == 0) || (count2 == 1)) {
    count2 = 16;
  }
  count2>>=1;
  for (count = 3; count >= 0; count--) {
    digitalWrite(motorPins[count], count2>>count&0x01);
  }
  delay(delayTime);
}

void moveBackward() {
  if ((count2 == 0) || (count2 == 1)) {
    count2 = 16;
  }
  count2>>=1;
  for (count = 3; count >= 0; count--) {
    digitalWrite(motorPins[3 - count], count2>>count&0x01);
  }
  delay(delayTime);
}

void loop() {
  val = analogRead(0);
  Serial.println(val);
  if (val > 540) {
    // move faster the higher the value from the potentiometer
    delayTime = 50 * (1023 - val) / 483;
    moveForward();
  } else if (val < 484) {
    // move faster the lower the value from the potentiometer
    delayTime = val * 50 / 484; 
    moveBackward();
  } else {
    delayTime = 1024;
  }
}