ESP32 Based Audio Player

Project Overview

This project demonstrates how to build a DIY audio player using the ESP32 microcontroller and LM386 amplifier IC. The ESP32's built-in Digital-to-Analog Converter (DAC) is utilised to play audio files in WAV format through a speaker, creating a simple yet functional audio playback system.

Project Link: ESP32 Based Audio Player on CircuitDigest

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Features

• 🎵 Play audio files using ESP32's DAC capability
• 🔊 Audio amplification using LM386 IC
• 📁 Support for WAV audio format
• 🎚️ Adjustable volume control through potentiometer
• ⚡ Simple circuit with minimal components
• 🔄 Continuous audio playback loop

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Components Required

Component	Quantity	Description
ESP32 Development Board	1	Main microcontroller
LM386 Amplifier Module	1	Audio amplification
8Ω Speaker	1	Audio output
Jumper Wires	As needed	Circuit connections
Breadboard (Optional)	1	For prototyping

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Circuit Diagram

Pin Connections

LM386 Amplifier Module	ESP32 Pin
VCC	VIN (5V)
GND	GND
IN	GPIO 25 (DAC1)

Speaker Connection: Connect the 8Ω speaker to the output pins of the LM386 amplifier module.

Circuit Notes

• GPIO 25 is one of the two DAC (Digital to Analog Converter) pins on the ESP32
• The LM386 amplifier module amplifies the weak audio signal from the ESP32
• Volume can be adjusted using the potentiometer on the LM386 module

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Software Requirements

Arduino IDE Setup

1. Arduino IDE (version 1.8 or higher)
2. ESP32 Board Support - Install via Board Manager
3. XT_DAC_Audio Library - Download from XTronical

Audio Processing Tools

1. Audacity - For audio file conversion and processing (Download here)
2. HxD Hex Editor - For generating hex codes from WAV files (Download here)

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Audio File Preparation

Step 1: Audio Conversion with Audacity

1. Open your audio file in Audacity
2. Change the Project Rate to 16000 Hz (8000-16000 Hz recommended for ESP32)
3. Navigate to File > Export > Export as WAV
4. Select the following settings:
   • File Type: WAV (Microsoft)
   • Encoding: Unsigned 8-bit PCM
5. Save the file

Step 2: Generate Hex Code

1. Open the WAV file in HxD Hex Editor
2. Press Ctrl+A to select all hex code
3. Go to Edit > Copy as > C to copy in C language format
4. Paste the code into a header file named SoundData.h

SoundData.h Format

const unsigned int sample[] = {
    // Paste your hex code here
};

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Code Structure

Main Libraries

#include "SoundData.h"      // Contains audio data in hex format
#include "XT_DAC_Audio.h"   // DAC audio library

Key Objects

XT_Wav_Class Sound(sample);        // WAV file object
XT_DAC_Audio_Class DacAudio(25,0); // DAC audio player on GPIO 25

Setup Function

void setup() {
    Serial.begin(115200);  // Initialize serial for debugging
}

Loop Function

void loop() {
    DacAudio.FillBuffer();              // Fill audio buffer
    if(Sound.Playing==false)            // Check if sound finished
        DacAudio.Play(&Sound);          // Play sound again
}

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Installation & Usage

Step 1: Library Installation

1. Download and install the XT_DAC_Audio library
2. Place it in your Arduino libraries folder

Step 2: Prepare Your Audio

1. Convert your audio file to WAV format (16000 Hz, 8-bit PCM)
2. Generate hex code using HxD Hex Editor
3. Create SoundData.h file with the hex data

Step 3: Upload Code

1. Connect ESP32 to your computer via USB
2. Select the correct board and port in Arduino IDE
3. Upload the sketch to ESP32

Step 4: Hardware Setup

1. Connect the LM386 amplifier module to ESP32 as per the circuit diagram
2. Attach the speaker to the amplifier output
3. Power up the ESP32

Step 5: Testing

1. Once powered, the ESP32 will automatically start playing the audio
2. Adjust volume using the potentiometer on the LM386 module
3. Monitor serial output for debugging

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Code Implementation

#include "SoundData.h"
#include "XT_DAC_Audio.h"

XT_Wav_Class Sound(sample);
XT_DAC_Audio_Class DacAudio(25,0);

uint32_t DemoCounter=0;

void setup() {
    Serial.begin(115200);
}

void loop() {
    DacAudio.FillBuffer();
    if(Sound.Playing==false)
        DacAudio.Play(&Sound);
    Serial.println(DemoCounter++);
}

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Troubleshooting

Problem: Only Static Noise

Solutions:

• Verify the audio file is in correct format (16000 Hz, 8-bit PCM)
• Check all connections, especially GPIO 25 to amplifier IN pin
• Ensure hex code is properly formatted in SoundData.h
• Verify amplifier module is powered correctly

Problem: No Sound Output

Solutions:

• Check speaker connections
• Verify LM386 module is receiving power (VIN and GND)
• Test speaker with another audio source
• Ensure GPIO 25 is properly connected

Problem: Low Volume

Solutions:

• Adjust potentiometer on LM386 module clockwise
• Use a higher wattage speaker
• Check amplifier module power supply

Problem: Distorted Audio

Solutions:

• Reduce sample rate in Audacity (try 8000 Hz)
• Lower the volume on amplifier module
• Ensure power supply is stable

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Technical Specifications

• Microcontroller: ESP32
• DAC Pin Used: GPIO 25 (DAC1)
• Audio Format: WAV (Unsigned 8-bit PCM)
• Sample Rate: 8000-16000 Hz (recommended)
• Amplifier IC: LM386
• Speaker Impedance: 8Ω
• Power Supply: 5V via USB or external source

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How It Works

1. Audio Storage: The audio file is converted to a hex code and stored in program memory as an array
2. DAC Conversion: ESP32's DAC converts digital audio data to analog voltage signals on GPIO 25
3. Amplification: LM386 amplifies the weak analog signal from ESP32
4. Audio Output: The amplified signal drives the speaker to produce audible sound
5. Continuous Playback: The code continuously checks if audio has finished and replays it in a loop

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Limitations

• Memory Constraints: ESP32's limited RAM restricts the length of audio files
• Audio Quality: 8-bit, low sample rate audio provides basic quality
• Format Support: Only WAV format is supported
• Mono Output: Single channel audio only

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Future Enhancements

• Add SD card support for larger audio files
• Implement multiple track playback
• Add touch/button controls for play/pause/skip
• Integrate Bluetooth audio streaming
• Display track information on OLED screen
• Add equaliser functionality
• Battery power option with charging circuit

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Resources

• Project Tutorial: CircuitDigest ESP32 Audio Player
• XT_DAC_Audio Library: XTronical Website
• Audacity: Official Website
• HxD Hex Editor: Official Download
• ESP32 Datasheet: Espressif Documentation
• LM386 Datasheet: Texas Instruments.
• ESP32: ESP32 Projects

License

This project is open-source and available for educational and personal use. Please take a look at the original CircuitDigest article for specific licensing information.

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Contributing

You can fix this project and submit pull requests for improvements. Suggestions and bug reports are welcome!

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Acknowledgments

• Circuit Digest for the original project tutorial
• XTronical for the XT_DAC_Audio library
• ESP32 community for continued support and development

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Contact & Support

For questions or support regarding this project, please visit the original project page or refer to the CircuitDigest community forums.

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Happy Making! 🎵🔧