Code:
/*
ESP32 I2S Microphone Sample
esp32-i2s-mic-sample.ino
Sample sound from I2S microphone, display on Serial Plotter
Requires INMP441 I2S microphone
*/
// Include I2S driver
#include <driver/i2s.h>
// Connections to INMP441 I2S microphone
#define I2S_WS 3
#define I2S_SD 4
#define I2S_SCK 2
// Use I2S Processor 0
#define I2S_PORT I2S_NUM_0
// Define input buffer length
#define bufferLen 64
int16_t sBuffer[bufferLen];
void i2s_install() {
// Set up I2S Processor configuration
const i2s_config_t i2s_config = {
.mode = i2s_mode_t(I2S_MODE_MASTER | I2S_MODE_RX),
.sample_rate = 44100,
.bits_per_sample = i2s_bits_per_sample_t(16),
.channel_format = I2S_CHANNEL_FMT_ONLY_LEFT,
.communication_format = i2s_comm_format_t(I2S_COMM_FORMAT_STAND_I2S),
.intr_alloc_flags = 0,
.dma_buf_count = 8,
.dma_buf_len = bufferLen,
.use_apll = false
};
i2s_driver_install(I2S_PORT, &i2s_config, 0, NULL);
}
void i2s_setpin() {
// Set I2S pin configuration
const i2s_pin_config_t pin_config = {
.bck_io_num = I2S_SCK,
.ws_io_num = I2S_WS,
.data_out_num = -1,
.data_in_num = I2S_SD
};
i2s_set_pin(I2S_PORT, &pin_config);
}
void setup() {
// Set up Serial Monitor
Serial.begin(115200);
Serial.println(" ");
delay(1000);
// Set up I2S
i2s_install();
i2s_setpin();
i2s_start(I2S_PORT);
delay(500);
}
void loop() {
// False print statements to "lock range" on serial plotter display
// Change rangelimit value to adjust "sensitivity"
int rangelimit = 3000;
Serial.print(rangelimit * -1);
Serial.print(" ");
Serial.print(rangelimit);
Serial.print(" ");
// Get I2S data and place in data buffer
size_t bytesIn = 0;
esp_err_t result = i2s_read(I2S_PORT, &sBuffer, bufferLen, &bytesIn, portMAX_DELAY);
if (result == ESP_OK)
{
// Read I2S data buffer
int16_t samples_read = bytesIn / 8;
if (samples_read > 0) {
float mean = 0;
for (int16_t i = 0; i < samples_read; ++i) {
mean += (sBuffer[i]);
}
// Average the data reading
mean /= samples_read;
// Print to serial plotter
Serial.println(mean);
}
}
}
