This project is a light control switch system. The main idea is to use a photoresistance sensor module to detect the ambient light level and, based on this detection, control a relay module. Hello, welcome to the SunFounder Raspberry Pi & Arduino & ESP32 Enthusiasts Community on Facebook! Dive deeper into Raspberry Pi, Arduino, and ESP32 with fellow enthusiasts. There are component fact sheets, information on calculating resistor and capacitor values, ce. Light activating and deactivating switches are simple to build when you are provided with a LDR (sensing element) and 555 (switch activator). LED is. Light Controlled Switch or Light Operated Switch (LOS) is electronic switch/relay that makes switching (on/off) based on light condition.