ESP32 Forum

Posted: **Thu Sep 19, 2019 9:29 am**

Hi

I wan't to play a sound file for a well timed period. I have for example a sound file of 20 seconds which I want to play for 5 milliseconds. Right now I'm using the following for this:

- ESP Wemos D32 pro (with SD card reader on board)
- i2s breakout: https://www.adafruit.com/product/3678
- i2s library (see attachment)

Please find my code below. It seems that I can only play the complete file or nothing. I can't stop the i2s.write() on a specific time. I also played around with the buffer, data[], .. but I can't get it right.
Any suggestions on how to solve this? I'm open to new libraries, idea's, ....

For the moment I solved the problem by making the sound files to the desired length. This is clearly not the most efficient way of reaching my goal.

Code: Select all

#include <WiFi.h>
#include "I2S.h"
#include <FS.h>
#include <SD.h>
#include <Wire.h>

#define SD_CS 4 // Chiçp select pin
#define AMP_SD 32 // Amplifier shut down pin

int intervalStartTime = 0;
int audioStartTime = 0;

const int offset = 0x2C;
char data[150016];

int number = 0;

void setup() {
  Serial.begin(115200);
  WiFi.mode(WIFI_OFF);
  pinMode(SD_CS, OUTPUT);
  digitalWrite(SD_CS, HIGH);

  pinMode(AMP_SD, OUTPUT);
  digitalWrite(AMP_SD, HIGH);

  if (!SD.begin(SD_CS)) {
    Serial.println("SD mount failed!");
  }
  else {
    Serial.println("SD mount succes!");
  }

  xTaskCreatePinnedToCore(output, "output", 10000, NULL, 1, NULL, 0);
  I2S_Init();

  File file = SD.open("/TB-250Hz.wav");  // 44100Hz, 16bit, stereo, linear PCM
  Serial.println(file.size());
  Serial.println(sizeof(char));
  file.seek(offset);
  file.readBytes(data, sizeof(data));
  file.close();
}

void output (void * parameters) {
  Serial.printf("Output loop pinned to core \t %d\n", xPortGetCoreID());
  for (;;) {

    // Play audio
    audioStartTime = millis();
    I2S_Write(data, sizeof(data));
    Serial.println(millis() - audioStartTime);
    while (millis() - audioStartTime < 5) {
      
    }

    Serial.println("..");
  }
}

void loop() {

}

ESP32 Forum

Play sound file for specific time

Play sound file for specific time