Arduino Nano ESP32 - MP3 Player

In this guide, we'll discover how to create an MP3 player using an ESP32, an MP3 player module, a Micro SD Card, and a speaker. The MP3 files, which can be music or recorded audio, are kept on the micro SD Card. The Arduino Nano ESP32 will be programmed to send commands to control the MP3 player module which song to pick from the SD Card, convert it into sound, and then send that sound to the speaker. We'll dive into the following aspects:

Afterward, you can take the code a step further by incorporating a potentiometer or rotary encoder to adjust the volume.

Hardware Preparation

1×Arduino Nano ESP32
1×USB Cable Type-C
1×Serial MP3 Player Module
1×Micro SD Card
1×3.5mm Aux Speaker
1×Breadboard
1×Jumper Wires
1×(Recommended) Screw Terminal Adapter for Arduino Nano

Or you can buy the following sensor kit:

1×DIYables Sensor Kit 30 types, 69 units
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Overview of Serial MP3 Player Module and Speaker

Serial MP3 Player Module Pinout

A serial MP3 player module has three interfaces:

  • The interface to Arduino Nano ESP32 includes 4 pins:
    • RX pin: data pin, needs to be connected a TX pin of Arduino Nano ESP32
    • TX pin: data pin, needs to be connected a RX pin of Arduino Nano ESP32
    • VCC pin: power pin, needs to be connected to VCC (5V)
    • GND pin: power pin, needs to be connected to GND (0V)
  • The interface to the speaker is a 3.5mm Aux output female jack.
  • The interface to the Micro SD Card is a Micro SD Card Socket in the back of the module.
Serial MP3 Player Module Pinout

Speaker Pinout

A speaker usually has two interfaces:

  • Audio signal interface: it is 3.5mm Aux male connector that connects to the MP3 player module
  • Poweer interface: it can be USB, 5V power adapter or any other power interface

How It Works

To get started, make sure you have the following:

  • Gather a collection of songs or recorded audio that you want to play and store them on a micro SD Card.
  • Insert the micro SD Card into the MP3 player module.
  • Connect the MP3 player module to the Arduino Nano ESP32 and connect the speaker to the MP3 player module. Also, ensure the speaker is connected to a power source.

Each MP3 file on the micro SD Card gets a ID, starting from 0. Then, you can tell the Arduino Nano ESP32 to do various things with the MP3 player module, such as:

  • Play: Start playing the selected song.
  • Pause: Pause the song.
  • Play Next: Move to the next song.
  • Play Previous: Go back to the previous song.
  • Change Volume: Adjust how loud the music is.

When the MP3 player module gets a command, it reads the MP3 file from the micro SD Card, turns it into an audio signal, and sends that signal to the speaker using a 3.5mm Aux connection.

Wiring Diagram

The wiring diagram between Arduino Nano ESP32 and MP3 player module

This image is created using Fritzing. Click to enlarge image

Arduino Nano ESP32 Code - Play Music

The below code plays the first song stored on the Micro SD Card.

/* * This Arduino Nano ESP32 code was developed by newbiely.com * * This Arduino Nano ESP32 code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/arduino-nano-esp32/arduino-nano-esp32-mp3-player */ #include <SoftwareSerial.h> #define CMD_PLAY_NEXT 0x01 #define CMD_PLAY_PREV 0x02 #define CMD_PLAY_W_INDEX 0x03 #define CMD_SET_VOLUME 0x06 #define CMD_SEL_DEV 0x09 #define CMD_PLAY_W_VOL 0x22 #define CMD_PLAY 0x0D #define CMD_PAUSE 0x0E #define CMD_SINGLE_CYCLE 0x19 #define DEV_TF 0x02 #define SINGLE_CYCLE_ON 0x00 #define SINGLE_CYCLE_OFF 0x01 #define ARDUINO_RX D8 // Arduino Nano Pin connected to the TX of the Serial MP3 Player module #define ARDUINO_TX D7 // Arduino Nano Pin connected to the RX of the Serial MP3 Player module SoftwareSerial mp3(ARDUINO_RX, ARDUINO_TX); void setup() { Serial.begin(9600); mp3.begin(9600); delay(500); // wait chip initialization is complete mp3_command(CMD_SEL_DEV, DEV_TF); // select the TF card delay(200); // wait for 200ms mp3_command(CMD_PLAY, 0x0000); // Play mp3 //mp3_command(CMD_PAUSE, 0x0000); // Pause mp3 //mp3_command(CMD_PLAY_NEXT, 0x0000); // Play next mp3 //mp3_command(CMD_PLAY_PREV, 0x0000); // Play previous mp3 //mp3_command(CMD_SET_VOLUME, 30); // Change volume to 30 } void loop() { } void mp3_command(int8_t command, int16_t dat) { int8_t frame[8] = { 0 }; frame[0] = 0x7e; // starting byte frame[1] = 0xff; // version frame[2] = 0x06; // The number of bytes of the command without starting byte and ending byte frame[3] = command; // frame[4] = 0x00; // 0x00 = no feedback, 0x01 = feedback frame[5] = (int8_t)(dat >> 8); // data high byte frame[6] = (int8_t)(dat); // data low byte frame[7] = 0xef; // ending byte for (uint8_t i = 0; i < 8; i++) { mp3.write(frame[i]); } }

Detailed Instructions

Arduino Nano ESP32 Code - Play Music with control buttons

The below code is an upgrade of the previous code. It adds foyr buttons to let you interact with MP3 player.

/* * This Arduino Nano ESP32 code was developed by newbiely.com * * This Arduino Nano ESP32 code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/arduino-nano-esp32/arduino-nano-esp32-mp3-player */ #include <SoftwareSerial.h> #include <ezButton.h> #define CMD_PLAY_NEXT 0x01 #define CMD_PLAY_PREV 0x02 #define CMD_PLAY_W_INDEX 0x03 #define CMD_SET_VOLUME 0x06 #define CMD_SEL_DEV 0x09 #define CMD_PLAY_W_VOL 0x22 #define CMD_PLAY 0x0D #define CMD_PAUSE 0x0E #define CMD_SINGLE_CYCLE 0x19 #define DEV_TF 0x02 #define SINGLE_CYCLE_ON 0x00 #define SINGLE_CYCLE_OFF 0x01 #define ARDUINO_RX D8 // Arduino Nano Pin connected to the TX of the Serial MP3 Player module #define ARDUINO_TX D7 // Arduino Nano Pin connected to the RX of the Serial MP3 Player module SoftwareSerial mp3(ARDUINO_RX, ARDUINO_TX); ezButton button_play(D2); // create ezButton object for pin D2 ezButton button_pause(D3); // create ezButton object for pin D3 ezButton button_next(D4); // create ezButton object for pin D4 ezButton button_prev(D5); // create ezButton object for pin D5 void setup() { Serial.begin(9600); mp3.begin(9600); delay(500); // wait chip initialization is complete mp3_command(CMD_SEL_DEV, DEV_TF); // select the TF card delay(200); // wait for 200ms button_play.setDebounceTime(50); // set debounce time to 50 milliseconds button_pause.setDebounceTime(50); // set debounce time to 50 milliseconds button_next.setDebounceTime(50); // set debounce time to 50 milliseconds button_prev.setDebounceTime(50); // set debounce time to 50 milliseconds } void loop() { button_play.loop(); // MUST call the loop() function first button_pause.loop(); // MUST call the loop() function first button_next.loop(); // MUST call the loop() function first button_prev.loop(); // MUST call the loop() function first if (button_play.isPressed()) { Serial.println("Play mp3"); mp3_command(CMD_PLAY, 0x0000); } if (button_pause.isPressed()) { Serial.println("Pause mp3"); mp3_command(CMD_PAUSE, 0x0000); } if (button_next.isPressed()) { Serial.println("Play next mp3"); mp3_command(CMD_PLAY_NEXT, 0x0000); } if (button_prev.isPressed()) { Serial.println("Play previous mp3"); mp3_command(CMD_PLAY_PREV, 0x0000); } } void mp3_command(int8_t command, int16_t dat) { int8_t frame[8] = { 0 }; frame[0] = 0x7e; // starting byte frame[1] = 0xff; // version frame[2] = 0x06; // The number of bytes of the command without starting byte and ending byte frame[3] = command; // frame[4] = 0x00; // 0x00 = no feedback, 0x01 = feedback frame[5] = (int8_t)(dat >> 8); // data high byte frame[6] = (int8_t)(dat); // data low byte frame[7] = 0xef; // ending byte for (uint8_t i = 0; i < 8; i++) { mp3.write(frame[i]); } }

The wiring diagram for the above code:

The wiring diagram between Arduino Nano ESP32 and MP3 player speaker

This image is created using Fritzing. Click to enlarge image

Now, you can modify the projects to add more functions, for example:

Video Tutorial

Function References