How to Generate a Beep?

  • Thanks for the reply. I cannot find any examples for this. I clicked through all the given examples and nothing came up when I searched "beep" or "tone" or "speaker". I looked through the library I have installed on arduino, and also this one that has more examples:

  • @akaf24

    Well.. so sorry... you are right!
    I was certain i took the code from there but i was wrong. It is on the main m5stack library
    check here:

    If i dont remember wrong (again) it worked for me.

    Sorry again.

  • The original m5stack uses an analog speaker amplifier circuit. The core 2 uses digital so you'll need to use something like in order to store files in flash/sd/internet and play them back over i2s.

    I've had great quality and volume coming through the speakers this way. I suggest you look into the github link I posted for examples, they have totally complete examples using internet sources but if you just read the examples on that github you can see how to adopt it for sd/spiffs files with ease.

  • @bricoms Thank you for the reply. I tried that example, but it did not work for me. I am using an M5 Stack core2 and that seems to be a library for just the Stack.

  • @jesse-schein haha wow, there's certainly a lot there. Thanks for this info. I just need to generate a simple beep once every few seconds, but it seems like I can only generate sound from from a wav or other file type? I was hoping there would be a tone() function, but I guess i'll just have to go through a few extra steps to get what I need.
    Edit: I just tried uploading some of these examples and they would not generate sound. I'll have to take a closer look at what's going on

  • @akaf24 You can try look at this:
    It use the same chip as Core2 and play beeps ;-) so you migth be able to just change the i2S pins and the you go ;-)

  • Just did a test, it will/can play a Beep om CORE2, just change Atom to CORE2 include, change the i2s pins and make one line a comment, the line not supported by CORE2.

    And yes, it is far to much code to get a Beep ;-)

  • thank you for the reply. I think I'm stuck on pin assignment. So on the back of my core2, it says BCLK is 12, LRCK is 0 and DATA is 0. But the example code also has "CONFIG_I2S_DATA_IN_PIN" and "SPEAKER_I2S_NUMBER" but I am not sure what to assign these as.

  • @akaf24 DATA should be 2 not 0, you dont need to change the last two items.

  • @agreedk thank you for reply. I keep getting a compile error. A beep isn't totally needed in my project so i'm just going to leave it out.

  • I haven't tried this but in the .h file there is something called Speaker.setBeep . That might just work.

    in the M5Stack.h file there is this.

        M5.Speaker.tone(uint32_t freq);
        M5.Speaker.tone(freq, time);
        M5.Speaker.setBeep(uint16_t frequency, uint16_t duration);

    And if you open up the example "FactoryTest" there is a section in the code that uses dacWrite to the speaker pin.

    void startupLogo() {
    static uint8_t brightness, pre_brightness;
    uint32_t length = strlen((char*)m5stack_startup_music);
    M5.Lcd.pushImage(0, 0, 320, 240, (uint16_t *)gImage_logoM5);
    for(int i=0; i<length; i++) {
    dacWrite(SPEAKER_PIN, m5stack_startup_music[i]>>2);

    brightness = (i/157);
    if(pre_brightness != brightness) {
    pre_brightness = brightness;

    The startup_music.c is found on another tab when you open the example code.

    // SAMPLES: 40000,
    // CHANNELS: 1,
    // SAMPLERATE: 20000,
    const unsigned char m5stack_startup_music[] = {

    Lots of HEX here*