Street Light ON OFF Starter with Photocell Sensor A street light ON/OFF starter with a photocell sensor is a system that automatically controls the operation of street lights based on the ambient light level. The photocell sensor, also known as a photoresistor or light-dependent resistor (LDR), detects the amount of light present in the environment and triggers the street lights to turn ON or OFF accordingly. Join CNC family for more life hacks with electricity and technical stuffs. #cncelectric