ESP32 - Sound Sensor

The sound sensor has the capability to detect the presence of sound in its surroundings. It can be utilized to create trendy sound-responsive projects like lights that activate with a clap or a pet feeder that responds to sound.

In this tutorial, we will learn how to use the ESP32 and a sound sensor to detect sound. We will delve into the following:

Following that, you have the flexibility to modify the code to trigger an LED or a light (using a relay) upon sound detection, or even enable a servo motor to rotate.

Hardware Used In This Tutorial

1×ESP-WROOM-32 Dev Module
1×USB Cable Type-C
1×Sound Sensor
1×Jumper Wires
1×(Optional) 5V Power Adapter for ESP8266
1×(Recommended) ESP32 Screw Terminal Adapter

Or you can buy the following sensor kit:

1×DIYables Sensor Kit 30 types, 69 units
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Introduction to Sound Sensor

The sound sensor can be used to detect sound in the surrounding environment. You can adjust the sensitivity of the detection by using the built-in potentiometer.


The sound sensor includes three pins:

  • VCC pin: needs to be connected to VCC (3.3V to 5V)
  • GND pin: needs to be connected to GND (0V)
  • OUT pin: is an output pin: HIGH if quiet and LOW if sound is detected. This pin needs to be connected to ESP32's input pin.
Sound Sensor Pinout
image source:

The sound sensor has a handy built-in potentiometer that lets you easily adjust its sensitivity. Additionally, it comes with two LED indicators:

  • One LED indicator shows the power status.
  • Another LED indicator indicates the sound state, turning on when sound is detected and off when it's quiet.

How It Works

The module includes a convenient built-in potentiometer that allows you to adjust the sound sensitivity. Here's how the output pin of the sensor behaves:

  • When sound is detected, the output pin is set to LOW.
  • When sound is not detected, the output pin is set to HIGH.

Wiring Diagram

ESP32 Sound Sensor Wiring Diagram

This image is created using Fritzing. Click to enlarge image

If you're unfamiliar with how to supply power to the ESP32 and other components, you can find guidance in the following tutorial: How to Power ESP32.

How To Program For Sound Sensor

  • Initializes the ESP32 pin to the digital input mode by using pinMode() function. For example, pin GPIO18
pinMode(18, INPUT);
  • Reads the state of the ESP32 pin by using digitalRead() function.
int soundState = digitalRead(18);

ESP32 Code - Detecting the sound

/* * This ESP32 code is created by * * This ESP32 code is released in the public domain * * For more detail (instruction and wiring diagram), visit */ #define SENSOR_PIN 18 // ESP32 pin GPIO18 connected to the OUT pin of the sound sensor int lastState = HIGH; // the previous state from the input pin int currentState; // the current reading from the input pin void setup() { // initialize serial communication at 9600 bits per second: Serial.begin(9600); // initialize the ESP32's pin as an input pinMode(SENSOR_PIN, INPUT); } void loop() { // read the state of the the ESP32's input pin currentState = digitalRead(SENSOR_PIN); if (lastState == HIGH && currentState == LOW) Serial.println("The sound has been detected"); else if (lastState == LOW && currentState == HIGH) Serial.println("The sound has disappeared"); // save the the last state lastState = currentState; }

Quick Instructions

  • If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE.
  • Copy the above code and open with Arduino IDE
  • Click Upload button on Arduino IDE to upload code to ESP32
  • Clap your hand in front of the sound sensor
  • See the result on Serial Monitor.
The sound has been detected The sound has disappeared The sound has been detected The sound has disappeared
Autoscroll Show timestamp
Clear output
9600 baud  

Please keep in mind that if you notice the LED status remaining constantly on or off, even when there is sound present, you may need to adjust the potentiometer to fine-tune the sound sensitivity of the sensor.

Now, we have the freedom to personalize the code and make it trigger an LED or a light when sound is detected. We can even make a servo motor rotate according to the sound input. For more detailed guidance and step-by-step instructions, you can refer to the tutorials provided at the end of this tutorial.


If you encounter any issues with the sound sensor's functionality, please consider the following troubleshooting steps:

  • Reduce vibrations: Mechanical vibrations and wind noise can affect the sound sensor's performance. To minimize these disturbances, try mounting the sound sensor on a stable surface.
  • Consider the sensing range: Keep in mind that this particular sound sensor has a limited sensing range of approximately 10 inches. For accurate readings, try producing sound closer to the sensor.
  • Check the power supply: Ensure that the power supply is clean and free from noise, as the sound sensor is sensitive to power supply interference due to its analog nature.

Video Tutorial

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Function References