Here's the core idea behind a sound–light controlled lighting fixture (often called “sound-and-light switch”): the lamp turns on only when it's dark enough (light sensor says “night”) and a sound event (clap/voice/door noise) is detected. It then stays on for a short time and turns off. In modern electronics and energy-saving applications, the sound-and-light controlled delay switch circuit board is a widely used smart control module. The sound control is to collect sound through a columnar microphone and generate a pulse signal. The. This project demonstrates a basic sound-based automation system using an Arduino Uno and a relay module to control an AC bulb via clap detection. The described circuit serves as a.