//  Sketch by R. Jordan Kreindler, written September 2016, to rotate
//    a stepper motor, pause 3 seconds each 90 degrees of turn, and reverse
//    direction after each full revolution

int aPin      = 2; //IN1: first end of the blue and yellow stator coil
int bPin      = 3; //IN2: first end of the pink 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 pink and orange stator coil
int direction = 0;

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

int delay1 = 2; // The delay between each step
int delay2 = 3000; // The delay after each 90 degree turn

int count  = 0; // The number of steps
int numberOfRotations = 0; // The number of times the rotor has
//   turned 360 degrees

void setup() {
  Serial.begin(9600);
  Serial.print("Motor started \n");
  // Set all pins as output to send output signals from the Arduino
  //   UNO to the coil windings
  pinMode(aPin,      OUTPUT);
  pinMode(bPin,      OUTPUT);
  pinMode(aPrimePin, OUTPUT);
  pinMode(bPrimePin, OUTPUT);

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

void loop() {
  // Send current to
  // 1. The aPin, and the bPin
  // 2. Then to the bPin and the aPrimePin
  // 3. Then to the aPrimePin and the bPrime Pin
  // 4. Then the bPrimePin and the aPin.
  // Thus producing steps with two coils activated at the same time
  //   to increase torque.

  // 1. Energize the blue yellow, and pink orange stator coils
  digitalWrite(aPin,      HIGH);
  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

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

  // 4. Energize the blue yellow, and in reverse current direction
  //    the pink orange coils
  digitalWrite(aPin,      HIGH);
  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;
  Serial.print("Number of steps = ");
  Serial.print(count);
  Serial.print("    Angle Rotated = ");
  Serial.print((count / 2048.00) * 360);
  Serial.println(" Degrees");

  if (count%512  == 0 ) delay(delay2); 
  if (count%2048 == 0 ) {
    direction = numberOfRotations%2;
    numberOfRotations = ++numberOfRotations;
    Serial.print("numberOfRotations = ");
    Serial.println(numberOfRotations);
    Serial.println("\n");
    count = 0;
    Serial.print("\nDirection = ");
    if(direction == 0) {
      Serial.println("clockwise");
      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 {
      Serial.println("counter-clockwise");
      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
    }
  }
}