I'm trying to make an audio streamer by using SPH0645 I2S MEMS mic and ESP32 DevKit. I found 2 code, First one is achieved by using MAX9814 Electret mic. The second one is I2S audio streaming but to ESP32 not from ESP32. I want to combine these 2 codes to make I2S streaming to the server. I wrote the working code done with analog output, I2S sample can be checked from link. If you help me to convert analog code to digital, I will be glad.

Streaming I2S Audio on ESP32

Streaming Audio from ESP32

/* Audio streamer with ESP32 and Adafruit elected microphone board. 
 * Created by Julian Schroeter.
#include <Arduino.h>
#include <WiFi.h>
#include <driver/adc.h>

#define AUDIO_BUFFER_MAX 800

uint8_t audioBuffer[AUDIO_BUFFER_MAX];
uint8_t transmitBuffer[AUDIO_BUFFER_MAX];
uint32_t bufferPointer = 0;

const char* ssid     = "YOUR SSID";
const char* password = "YOUR PASSWORD";
const char* host     = "YOUR SERVER IP ADDRESS";

bool transmitNow = false;

WiFiClient client;

hw_timer_t * timer = NULL; // our timer

void IRAM_ATTR onTimer() {
  portENTER_CRITICAL_ISR(&timerMux); // says that we want to run critical code and don't want to be interrupted
  int adcVal = adc1_get_voltage(ADC1_CHANNEL_0); // reads the ADC
  uint8_t value = map(adcVal, 0 , 4096, 0, 255);  // converts the value to 0..255 (8bit)
  audioBuffer[bufferPointer] = value; // stores the value
  if (bufferPointer == AUDIO_BUFFER_MAX) { // when the buffer is full
    bufferPointer = 0;
    memcpy(transmitBuffer, audioBuffer, AUDIO_BUFFER_MAX); // copy buffer into a second buffer
    transmitNow = true; // sets the value true so we know that we can transmit now
  portEXIT_CRITICAL_ISR(&timerMux); // says that we have run our critical code

void setup() {

  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {

  Serial.println("WiFi connected");
  Serial.println("MY IP address: ");
  adc1_config_width(ADC_WIDTH_12Bit); // configure the analogue to digital converter
  adc1_config_channel_atten(ADC1_CHANNEL_0, ADC_ATTEN_0db); // connects the ADC 1 with channel 0 (GPIO 36)

  const int port = 4444;
  while (!client.connect(host, port)) {
    Serial.println("connection failed");

  Serial.println("connected to server");

  timer = timerBegin(0, 80, true); // 80 Prescaler
  timerAttachInterrupt(timer, &onTimer, true); // binds the handling function to our timer 
  timerAlarmWrite(timer, 125, true);


void loop() {
  if (transmitNow) { // checks if the buffer is full
    transmitNow = false;
    client.write((const uint8_t *)audioBuffer, sizeof(audioBuffer)); // sending the buffer to our server
  • You need the esp-adf audio library.
    – Mike
    Jun 9 '20 at 22:53

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