This is the 4th tutorial in the Controlling the LEDs series. In order to make this tutorial more familiar, the set-up of this project is similar to the third tutorial in this series about controlling multiple LEDs. But for this one, an array of LEDs shall be controlled using the sound module.

This fun activity is very simple to do and will only take a few minutes to set up!

This project recreates the audio spectrum bars commonly seen when playing music on a phone or a media player. Instead of visible square bars, a row of six LEDs lights up according to the sound intensity picked up by the microphone. It is a simple, beginner-friendly way to turn sound into light.

Gather everything below before you start. This is your checklist — names, models, and versions only.

You can buy all this hardware at Createlabz.

All required files are available in the project repository. Download the repository before proceeding to the Software Setup section.

Repository: github.com/createlabz/createlabz-public — arduino-upgradedStarterKit/SoundModuleLED

Here is what each component does and why it is part of this project.

When using a recorder from a mobile phone or playing music, an audio spectrum is usually noticed. This audio spectrum is often visualized as square bars. The bars vary according to the emitted sound. This tutorial will do the same thing. However, instead of having visible square bars as an output, the LEDs will be utilized to mimic the sound it picks up from the input. The key component in this project is the sound module.

The microphone sound sensor is a sound level detector module with an electric condenser microphone and a built-in potentiometer to adjust its sensitivity. This project makes use of the sound sensor available in the Upgraded Arduino Kit. Thus, this tutorial will be using the KY038 Microphone Module.

How It Works

Sensitivity (Potentiometer)

Six LEDs (blue, green, and red) act as the output of the project. Each LED is assigned a threshold value, so as the detected sound gets louder, more LEDs light up — mimicking an audio spectrum.

Wire the components to the board using the tables below.

Wiring Diagram

1. Place all the components on the breadboard.
2. Connect the sound module — Analog Out to A0, GND to GND, and +V to 5V.
3. Connect the positive leg of each LED to its assigned digital pin (13, 12, 11, 10, 9, 8).
4. Connect the other leg of each LED to GND through a resistor (220 ohm for the first five LEDs and 330 ohm for the sixth).
5. Adjust the potentiometer on the sound module as needed while testing.

Follow these steps in order. Do not skip any step.

1. Download and install the latest version of the Arduino IDE from arduino.cc.
2. Accept the default settings during installation.

Use exactly these settings in your IDE. Wrong settings will cause upload failures.

1. Download the project repository from the Project Repository note above.
2. Open the SoundModuleLED sketch (.ino) in the Arduino IDE.
3. Select the correct board and port.
4. Click Upload.

Copy each file below into the correct location as described in the Software Setup section. Read the Code Breakdown section to understand what each part does.

The code below shows how to check the Serial Monitor for the maximum and minimum threshold.

int ledblu1 = 13;
int ledblu2 = 12;
int ledgrn3 = 11;
int ledgrn4 = 10;
int ledred5 = 9;
int ledred6 = 8;

int soundMod = A0;
int soundOut = 0;

void setup() {
  pinMode(ledblu1, OUTPUT);
  pinMode(ledblu2, OUTPUT);
  pinMode(ledgrn3, OUTPUT);
  pinMode(ledgrn4, OUTPUT);
  pinMode(ledred5, OUTPUT);
  pinMode(ledred6, OUTPUT);

  pinMode(soundMod, INPUT);
  Serial.begin(9600);
}

void loop() {
  soundOut = analogRead(soundMod);

  Serial.println(soundOut); //This is done to know the min and max threshold for the sound sensor
}

The code below is the portion for controlling the LEDs.

// when the sensor detects a signal, LED flashes
// Once min and max threshold have been obtained, divide the values per LED

//Minimum Threshold
if (soundOut >= 495) {
  digitalWrite(ledblu1, HIGH);
}
else {
  digitalWrite(ledblu1, LOW);
}

if (soundOut >= 500) {
  digitalWrite(ledblu2, HIGH);
}
else {
  digitalWrite(ledblu2, LOW);
}

if (soundOut >= 510) {
  digitalWrite(ledgrn3, HIGH);
}
else {
  digitalWrite(ledgrn3, LOW);
}

if (soundOut >= 515) {
  digitalWrite(ledgrn4, HIGH);
}
else {
  digitalWrite(ledgrn4, LOW);
}

if (soundOut >= 520) {
  digitalWrite(ledred5, HIGH);
}
else {
  digitalWrite(ledred5, LOW);
}

//Max Threshold
if (soundOut >= 525) {
  digitalWrite(ledred6, HIGH);
}
else {
  digitalWrite(ledred6, LOW);
}

Here is what each part of the code does. Read this after uploading.

1. The program reads the sound level from the sound module using analogRead().
2. The value is printed to the Serial Monitor so the minimum and maximum thresholds can be observed.
3. Each LED turns on when the sound level reaches its assigned threshold.
4. Each LED turns off when the sound level drops below its assigned threshold.
5. The loop repeats, producing the audio-spectrum bar effect.

After uploading, verify each of the following to confirm the system is working correctly.

Once the code is uploaded, open the Serial Monitor by clicking the button on the upper right of the Arduino IDE.

The Serial Monitor will start printing the values taken from the sound module.

From this, take note of the lowest value when the room is silent and the highest value when the loudest sound is played.

Once the minimum and maximum thresholds are obtained, divide the values per LED. In the sample code, the thresholds used are 495, 500, 510, 515, 520, and 525.

This can still be adjusted. Another option for adjusting is by turning the potentiometer found on the sound module.

The image and video below show the working system. Use these to verify your output matches what is expected.

System Setup

Video Demonstration

The music reactive LED is a fun and easy project to do. We used a set-up similar to part 3 of the Controlling the LEDs series in hopes of giving a sense of familiarity. This project also tackled the basic functionality of the sound sensor, and the use of the Serial Monitor to obtain the minimum and maximum thresholds was also observed.

• Adjusting LED Brightness using a Potentiometer
• Adjusting LED Brightness using a Photoresistor
• Turning On/Off Multiple LEDs and Buzzer

• Split the sound into frequency bands (for example, using an FFT library) to display a true audio spectrum.
• Use an LED strip or RGB LEDs to create smoother color transitions.
• Add a potentiometer input so the sensitivity can be adjusted without editing the code.
• Combine the digital output of the sound module with the analog reading for more precise triggering.

The following references were used while building this project.

• Square Bars on Audio Spectrum
  https://community.fxhome.com/discussion/49382/square-bars-on-audio-spectrum
• KY038 Microphone Module and Arduino Example
  http://arduinolearning.com/code/ky038-microphone-module-and-arduino-example.php
• Arduino Sound Sensor with LED
  https://www.instructables.com/Arduino-Sound-Sensor-with-LED/
• KY-038 Microphone Sound Sensor Module
  https://sensorkit.en.joy-it.net/index.php?title=KY-038_Microphone_sound_sensor_module

• Nolf Ivan Labios

Quality Checked by:
• Elijah Joseph Orias
• Lukie-Mar Lonzaga
• Miles Darren Bagnol