LDR Sensor

Measures ambient light level using a photoresistor whose resistance falls as light increases. The analogue output gives a continuous reading for tracking brightness through the day, while the digital output trips at a threshold set by the onboard potentiometer — useful for switching a light on at dusk. Cheap, simple and reliable for relative light sensing, though it is not calibrated in lux and its response varies between individual sensors. Both analogue level and adjustable digital threshold; Ideal for automatic night lighting; Very low cost and simple to use; Indicator LED shows threshold state