task main()
{
  int lowIR = 1000; //Arbitrary high number so the calibration will work
  int highIR = 0;

  //Auto-calibration ended by button press. The button will begin the line following.
  //During this time, the robot should be moved so that it sees both black and white -
  //you could 'scan' it across the line.
  while(!SensorValue[button]) {
    if(SensorValue[centerIR] > highIR) {
      highIR = SensorValue[centerIR];
      } else if(SensorValue[centerIR] < lowIR) {
      lowIR = SensorValue[centerIR];
    }
  }

  //Set threshold as the average of light and dark.
  int threshold = (lowIR + highIR) / 2;

  // Light following loop
  while(true)
  {
    // RIGHT sensor sees dark:
    if(SensorValue(rightIR) > threshold)
    {
      // counter-steer right:
      motor[leftServo]  = 40;
      motor[rightServo] = 0;
    }
    // CENTER sensor sees dark:
    if(SensorValue(centerIR) > threshold)
    {
      // go straight
      motor[leftServo]  = 40;
      motor[rightServo] = 40;
    }
    // LEFT sensor sees dark:
    if(SensorValue(leftIR) > threshold)
    {
      // counter-steer left:
      motor[leftServo]  = 0;
      motor[rightServo] = 40;
    }
  }
}