This Arduino Light sensor circuit is a simple example that shows you how to connect light sensors such as photoresistors, photodiodes, and phototransistors, to an Arduino. The module provides two outputs: a digital output (LOW/HIGH) and an analog output. You'll. This tutorial is a comprehensive, practical guide to the LM393 Light Detection Sensor Module (Leobot Product #222). If you are interested in reading the. Light detection is a fundamental aspect of many projects, ranging from automatic light switches to regulated lighting systems. It is an analog component, with values ranging between 0 and.