Keyestudio ESP32 - 7.Code Explanation; Project 21: Sound Controlled LED; 1. Description; 2. Working Principle

To Next Page

To Previous Page

ESP32 Starter Kit

7.Code Explanation

Read the analog value of photoresistor by setting the pin.

9.2.24 Project 21: Sound Controlled LED

1. Description

Sound controlled LED is a device used to detect sound in a way that controls the brightness of LED, which is composed

of a Arduino board and some components. It can connect to multiple sensors such as microphones. It converts sound

to changing voltage signal to be received by Arduino to control the LED on and oﬀ.

2. Working Principle

When detecting a sound, the electret ﬁlm in microphone vibrates, which changes the capacitance and generates a subtle

change of voltage.

Next, we make use of LM386 chip to build a proper circuit to amplify the detected sound up to 200 times, which can

be adjusted by a potentiometer. Rotate it clockwise to enlarge the times.

9.2. Scratch Project 279