How to Use ESP32 for I2S Audio Playback and Recording with DAC and Mic

Introduction

The ESP32 is a versatile microcontroller that supports I2S (Inter-IC Sound) for audio playback and recording. In this tutorial, we will explore how to set up the ESP32 to play audio using an external I2S DAC and record audio using a microphone in PCM format. By following these steps, you’ll be able to create your own audio applications using the ESP32.

Prerequisites

• Basic knowledge of Arduino IDE and ESP32 programming.
• ESP32 board.
• External I2S DAC (e.g., PCM5102).
• I2S microphone (e.g., INMP441).
• Jumper wires for connections.
• Arduino IDE installed with ESP32 board support.

Parts/Tools

• ESP32 Development Board
• External I2S DAC (PCM5102)
• I2S Microphone (INMP441)
• Jumper Wires
• Computer with Arduino IDE

Steps

1. Wiring the Components
   • Connect the I2S DAC to the ESP32:

     
     Pin ESP32      | Pin DAC
     ----------------|--------
     GPIO 25 (BCK)  | BCK
     GPIO 26 (LRCK) | LRCK
     GPIO 27 (DATA) | DATA
     GND             | GND
     VCC             | VCC
                     

   • Connect the I2S microphone to the ESP32:

     
     Pin ESP32       | Pin Microphone
     -----------------|---------------
     GPIO 22 (BCK)   | BCK
     GPIO 23 (LRCK)  | LRCK
     GPIO 21 (DATA)  | DATA
     GND              | GND
     VCC              | VCC
                     

2. Setting Up the Arduino IDE
   1. Open the Arduino IDE.
   2. Install the required libraries:
      • Navigate to Sketch > Include Library > Manage Libraries…
      • Search for and install the Arduino I2S library.
3. Writing the Code
   1. Create a new sketch and include the necessary libraries:

      
      #include <I2S.h>
      #include <driver/i2s.h>
                      

   2. Define the I2S configuration:

      
      void setup() {
          I2S.begin(I2S_PHILIPS_MODE, 44100, I2S_BITS_PER_SAMPLE_16BIT);
      }
                      

   3. Implement audio playback:

      
      void playAudio() {
          // Example buffer with audio data
          uint8_t audioData[512]; // Fill this buffer with PCM data
          I2S.write(audioData, sizeof(audioData));
      }
                      

   4. Implement audio recording:

      
      void recordAudio() {
          uint8_t audioData[512];
          I2S.read(audioData, sizeof(audioData));
          // Process audioData as needed
      }
                      

4. Uploading the Code
   • Connect the ESP32 to your computer via USB.
   • Select the correct board and port in the Arduino IDE:
   • Click on Upload to compile and upload your code.
5. Testing the Setup
   • Open the Serial Monitor to see debug messages.
   • Trigger the audio playback and recording functions to test functionality.

Troubleshooting

• Issue: No sound from DAC
  • Check your wiring connections to ensure they are correct.
  • Verify the power supply to the DAC.
  • Ensure that the audio data being sent is valid PCM data.
• Issue: No audio recording
  • Confirm that the microphone is powered properly.
  • Check the microphone connections and ensure they match the code.
  • Use a logic analyzer to check if data is being read from the microphone.

Conclusion

In this tutorial, we successfully set up the ESP32 for I2S audio playback and recording using an external I2S DAC and microphone. By following the steps outlined, you can create your own audio projects and expand your understanding of audio processing with the ESP32 microcontroller.