ESP32 Forum

Posted: **Thu Dec 30, 2021 4:52 am**

I am using an ESP32 to build a toy project. The toy has a shooting sound activated by a button/trigger (GPIO input).
I am using this library and examples for some test code to see if I can get the performance or responsiveness I am looking for with the sound effects over I2S:
https://github.com/schreibfaul1/ESP32-audioI2S/wiki

I have two problems:
1) Lag/delay from the time the user presses the button until the sound is heard is delayed (~1 second)
2) If the user presses the button before the sound is finished playing I need to start the sound over again at the beginning.

What I have tried:
I originally started using the DFplayer mp3 module https://www.robotshop.com/en/dfplayer-m ... uTEALw_wcB but I quickly ran into issue #1. Too much delay between the time the user presses the button and when the short sound clip is played. It also took too long to issue a new command over the I2C to start playing the file over again if the user presses the button before the play is over.

Next, I tried to using I2S with a MAX98357A chip combined with WAV files located on an SD card. The lag issue was improved somewhat but still some delay in playing the file initially. However, for issue #2, I can seem to rapidly reset the play to the beginning to give rapid shot sound effects.

https://www.aliexpress.com/item/3304366 ... 85648d69e4

I was going to try just running the sound effect out of RAM but I haven't found a ton of great libraries that support playing WAVs direct from memory and I am not sure it would even help with my two issues.

MY QUESTION:

Based on what I am trying to do. What is the best way to get very low latency sound effects using the ESP32? Essentially, I have a gunshot.wav file and for single shot effect I want to quickly play it when a button is pressed followed by some other sound effects, but I need some pretty low latency for a positive experience. If the user rapidly presses the button I want to just keep restarting the sound effect.

Here is some example code I was using for testing:

Code: Select all

#include "Audio.h"
#include "SD.h"
#include "FS.h"

// Digital I/O used
#define SD_CS          5
#define SPI_MOSI      23
#define SPI_MISO      19
#define SPI_SCK       18
#define I2S_DOUT      25
#define I2S_BCLK      27
#define I2S_LRC       26

Audio audio;
const int ctrl_trigger = 4; // trigger, GND=fire

boolean old_button = false;

void setup(){
    pinMode(ctrl_trigger,INPUT_PULLUP);
    pinMode(SD_CS, OUTPUT);
    digitalWrite(SD_CS, HIGH);
    SPI.begin(SPI_SCK, SPI_MISO, SPI_MOSI);
    Serial.begin(115200);
    SD.begin(SD_CS);
    audio.setPinout(I2S_BCLK, I2S_LRC, I2S_DOUT);
    audio.setVolume(8); // 0...21
    audio.forceMono(true);
    
}

void loop(){

  audio.loop();

if (old_button != (digitalRead(ctrl_trigger)==LOW)){
    
    if (audio.isRunning()){
      audio.setAudioPlayPosition(0);
    }
    else {audio.connecttoFS(SD, "01_shot_umt.wav");}
  }
  
 old_button = (digitalRead(ctrl_trigger)==LOW);
  
}

// optional
void audio_info(const char *info){
    Serial.print("info        "); Serial.println(info);
}
void audio_id3data(const char *info){  //id3 metadata
    Serial.print("id3data     ");Serial.println(info);
}
void audio_eof_mp3(const char *info){  //end of file
    Serial.print("eof_mp3     ");Serial.println(info);
}
void audio_showstation(const char *info){
    Serial.print("station     ");Serial.println(info);
}
void audio_showstreaminfo(const char *info){
    Serial.print("streaminfo  ");Serial.println(info);
}
void audio_showstreamtitle(const char *info){
    Serial.print("streamtitle ");Serial.println(info);
}
void audio_bitrate(const char *info){
    Serial.print("bitrate     ");Serial.println(info);
}
void audio_commercial(const char *info){  //duration in sec
    Serial.print("commercial  ");Serial.println(info);
}
void audio_icyurl(const char *info){  //homepage
    Serial.print("icyurl      ");Serial.println(info);
}
void audio_lasthost(const char *info){  //stream URL played
    Serial.print("lasthost    ");Serial.println(info);
}
void audio_eof_speech(const char *info){
    Serial.print("eof_speech  ");Serial.println(info);
}

Code: Select all

info        buffers freed, free Heap: 286600 bytes
info        Reading file: "/01_shot_umt.wav"
info        stream ready
info        FormatCode: 1
info        DataRate: 44100
info        DataBlockSize: 2
info        Audio-Length: 41364
info        syncword found at pos 0
info        Channels: 1
info        SampleRate: 22050
info        BitsPerSample: 16
info        BitRate: 352800
info        syncword found at pos 0
info        Channels: 1
info        SampleRate: 22050
info        BitsPerSample: 16
info        BitRate: 352800
info        syncword found at pos 0
info        Channels: 1
info        SampleRate: 22050
info        BitsPerSample: 16
info        BitRate: 352800
info        syncword found at pos 0
info        Channels: 1
info        SampleRate: 22050
info        BitsPerSample: 16
info        BitRate: 352800
info        End of file "/01_shot_umt.wav"
eof_mp3     /01_shot_umt.wav

Posted: **Sat Nov 12, 2022 8:02 pm**

Hi there,
Were you able to find the solution to the problem?
I ran into the same issue and also tried DFPlayer.
The best results I had with Adafruit Audio FX board:https://www.adafruit.com/product/2342
They have 2Mb and 16Mb versions, but it takes more space and requires audio files to be saved into the flash memory rather than using an SD card, which is not always desirable.
Hope this helps.
Gus

ESP32 Forum

How to get more responsive sound effects???

How to get more responsive sound effects???

Re: How to get more responsive sound effects???