//  Sketch by R. Jordan Kreindler, written September 2016, to rotate
//     a stepper motor, pause 1 seconds each 180 degrees of turn, reverse
//     direction after each full revolution. Turn on red LED if clockwise
//     rotation and green LED if counter-clockwise

int aPin      = 2; //IN1: first end of the blue and yellow stator coil
int bPin      = 3; //IN2: first end of the white and orange stator coil
int aPrimePin = 4; //IN3: second end of the blue and yellow stator coil
int bPrimePin = 5; //IN4: second end of the White and orange stator coil
int redLED    = 6; // redLED on if rotor turning clockwise
int greenLED  = 7; // greenLED on if rotor turning counter-clockwise
int count     = 0; // The number of turns
int delay1    = 15; // Delay between steps
int delay2 = 1000; // Pause at 180 degrees
int direction = 2; // Direction flag: 0 = clockwise; else = counter-clockwise
int numberOfRotations = 0;

// We do not connect IN5, IN6, or IN7

void setup() {

  // Set all pins as output to send output signals from the Arduino
  //   UNO to the coil windings of the stator
  pinMode(aPin,      OUTPUT);
  pinMode(bPin,      OUTPUT);
  pinMode(aPrimePin, OUTPUT);
  pinMode(bPrimePin, OUTPUT);
  // Set LED pins for output
  pinMode(redLED,    OUTPUT);
  pinMode(greenLED,  OUTPUT);

  // Start with all coils off
  digitalWrite(aPin,      LOW);
  digitalWrite(bPin,      LOW);
  digitalWrite(aPrimePin, LOW);
  digitalWrite(bPrimePin, LOW);
}

void loop() {
  direction = numberOfRotations % 2;
  if (direction == 1) {
    digitalWrite(redLED,   LOW);
    digitalWrite(greenLED, HIGH);
  }
  else {
    digitalWrite(greenLED, LOW);
    digitalWrite(redLED,   HIGH);
  }

  // Send current to the apin, and then the bpin
  //   then reverse the current and send reversed current
  //   to aPrimePin and then bPrimePin.

  // 1. Energize the blue yellow stator coil
  digitalWrite(aPin,      HIGH);
  digitalWrite(bPin,      LOW);
  digitalWrite(aPrimePin, LOW);
  digitalWrite(bPrimePin, LOW);
  // Allow some delay between energizing the coils to allow
  //  the stepper rotor time to respond.
  delay(delay1); // So, delay1 microseconds

  // 2. Reverse current direction and energize the blue yellow stator coil
  digitalWrite(aPin,      LOW);
  digitalWrite(bPin,      LOW);
  digitalWrite(aPrimePin, HIGH);
  digitalWrite(bPrimePin, LOW);
  // Allow some delay between energizing the coils to allow
  //  the stepper rotor time to respond.
  delay(delay1); // So, delay1 microseconds

  // 3. Energize the blue yellow stator coil
  digitalWrite(aPin,      LOW);
  digitalWrite(bPin,      HIGH);
  digitalWrite(aPrimePin, LOW);
  digitalWrite(bPrimePin, LOW);
  // Allow some delay between energizing the coils to allow
  //  the stepper rotor time to respond.
  delay(delay1); // So, delay1 microseconds

  // 4. Reverse current direction and energize the white orange stator coil
  digitalWrite(aPin,      LOW);
  digitalWrite(bPin,      LOW);
  digitalWrite(aPrimePin, LOW);
  digitalWrite(bPrimePin, HIGH);
  // Allow some delay between energizing the coils to allow
  //  the stepper rotor time to respond.
  delay(delay1); // So, delay1 microseconds

  count = count + 4;

  if (count == 100) delay(delay2);
  if (count == 200) {
    delay(delay2);
    numberOfRotations = ++numberOfRotations;
    count = 0;
    if (direction == 0) {
      aPin      = 5; //IN1: first end of the blue and yellow stator coil
      bPin      = 4; //IN2: first end of the pink and orange stator coil
      aPrimePin = 3; //IN3: second end of the blue and yellow stator coil
      bPrimePin = 2; //IN4: second end of the pink and orange stator coil
    }
    else {
      aPin      = 2; //IN1: first end of the blue and yellow stator coil
      bPin      = 3; //IN2: first end of the pink and orange stator coil
      aPrimePin = 4; //IN3: second end of the blue and yellow stator coil
      bPrimePin = 5; //IN4: second end of the pink and orange stator coil
    }
  }
}