/*this works with both motors turning in unison, with the positive of each motor on the chip end of the motor connectors.
   * pin 12 goes to IN1, pin 8 goes to IN3. pin 12 & 8 are FORWARD when high and 9 & 13 LOW. 
   * see hookup image in lesson, I have the RIGHT motor going to MOTOR B
   */
  const int threshold = 50; //This is the threshold I chose based on previous experimenting in IR lesson, to deduce when we're close to an obstacle
  
void setup() {
  // put your setup code here, to run once:
  pinMode (13, OUTPUT); // setup our control pins as outputs.
  pinMode (12, OUTPUT);
  pinMode (11, OUTPUT);
  pinMode (10, OUTPUT);
  pinMode (9, OUTPUT);
  pinMode (8, OUTPUT);
  
}

void loop() {
  // put your main code here, to run repeatedly:
  //**start off by simply running forward at controlled speed in a straight line
  digitalWrite (12, HIGH); //set both right and left motors for forward rotation
  digitalWrite (13, LOW);  
  digitalWrite (8, HIGH);  
  digitalWrite (9, LOW);
  //drive forward on PWM, attempt a straight line for half a second
  analogWrite (11, 125);
  analogWrite (10, 125);
  if (analogRead (A0) < threshold) { //we've detected an obstacle, let's make a series of instructions backing up and turning then resuming forward movement
    analogWrite (11, 0); //first, stop all movement
    analogWrite (10, 0);
    delay (500); //let's just pause a second before we rotate
    digitalWrite (8, LOW); //set the right motor for reverse rotation
    digitalWrite (9, HIGH);  
    //rotate clockwise on the spot, so as not to back into anything
    digitalWrite (11, HIGH);
    digitalWrite (10, HIGH);
    delay (300); //we'll time a rotation of about 1/2 second
    digitalWrite (11, LOW); //stop both motors
    digitalWrite (10, LOW);
    delay (500); //let's just pause a second after rotation
    //we've finished the turn now, we'll just let the robot loop back to its forward movement
  }
}