if (this->pin_count == 4) {
    switch (thisStep) {
      case 0:    // 1100
      digitalWrite(motor_pin_1, HIGH);
      digitalWrite(motor_pin_2, HIGH);
      digitalWrite(motor_pin_3, LOW);
      digitalWrite(motor_pin_4, LOW);
      break;
      case 1:    // 0110
      digitalWrite(motor_pin_1, LOW);
      digitalWrite(motor_pin_2, HIGH);
      digitalWrite(motor_pin_3, HIGH);
      digitalWrite(motor_pin_4, LOW);
      break;
      case 2:    //0011
      digitalWrite(motor_pin_1, LOW);
      digitalWrite(motor_pin_2, LOW);
      digitalWrite(motor_pin_3, HIGH);
      digitalWrite(motor_pin_4, HIGH);
      break;
      case 3:    //1001
      digitalWrite(motor_pin_1, HIGH);
      digitalWrite(motor_pin_2, LOW);
      digitalWrite(motor_pin_3, LOW);
      digitalWrite(motor_pin_4, HIGH);
      break;