/* seek.nqc
 *
 * Drive towards a bright light.  As long as the light
 * sensor sees a bright light, drive forward.  Otherwise
 * try to find the light first by spinning in place.
 * After 3 seconds of spinning, try driving forward
 * to a new location and then continue spinning.
 */
  
// motors and sensors
#define LEFT    OUT_A
#define RIGHT   OUT_C
#define EYE     SENSOR_2

// timing
#define SEEK_MAX_TIMER      30  // 3 seconds
#define SEEK_FWD_TIME       100 // 1 second

// threshold for light sensor
#define THRESHOLD   65

task main()
{
	// setup sensor and start driving
	SetSensor(EYE, SENSOR_LIGHT);
	OnFwd(LEFT+RIGHT);
	
	while(true)
	{
		// wait until too dark
		until(EYE < THRESHOLD);
		
		// start spinning and reset timer
		PlayTone(440, 10);
		Rev(LEFT);
		ClearTimer(0);
		
		while(EYE < THRESHOLD)
		{
			if (Timer(0) > SEEK_MAX_TIMER)
			{
				// spent too long spinning...
				// move forward a bit
				Fwd(LEFT);
				Wait(SEEK_FWD_TIME);
				
				// continue spinning and reset timer
				Rev(LEFT);
				ClearTimer(0);
			}
		}
		
		// found the light, resume
		PlayTone(880, 10);
		Fwd(LEFT);
	}
}