 	moveBothMotors(0, forward, 0, forward);
 
 	// print the calibration minimum values measured when emitters were on
-	for (byte i = 0; i < sizeof(sensorPins); i++)
+	for (unsigned char i = 0; i < sizeof(sensorPins); i++)
 	{
 		Serial.print(qtra.calibratedMinimumOn[i]);
 		Serial.print(' ');

	pinMode(13, OUTPUT);

	//init LEDs
	for (byte i = 0; i < sizeof(ledPins); i++)
	{
		pinMode(ledPins[i], OUTPUT);
	}

#pragma region "Diagnostics"
void printSensorValues()
{
	for (unsigned char i = 0; i < sizeof(sensorPins); i++)
	{
		Serial.print(sensorValues[i]);
		Serial.print('\t');
