A2DP ESP32 relay when playing music

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1

Hi I'm using this example from visual micro for a bluetooth speaker.

I can see in the serial plotter that when music starts to play the "state" is displayed. what im trying to do is when this state is "started" to turn on a relay and turn off if its not. ive tried an if statement but failed miserably. i was wondering if someone could help.

/*
  Streaming data from Bluetooth to internal DAC of ESP32
  Using Library: https://github.com/pschatzmann/ESP32-A2DP

  Copyright (C) 2020 Phil Schatzmann
  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.
  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.
  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

// Connect one side of speaker to GND, the other to GPIO25
// Can use existing speakers / headphones --> https://i.pinimg.com/originals/4e/72/72/4e72729dba13164ad78586395fe11873.png

// ==> Example to use built in DAC of ESP32

#include "BluetoothA2DPSink.h"

int Relay  = 2;                 // Digital pin D5

BluetoothA2DPSink a2dp_sink;

// VolumeChanged doesnt work
int volume = 0;
void volumeChanged(int newVolume) {
    Serial.println(newVolume);
    volume = newVolume;
}

// for esp_a2d_connection_state_t see https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/bluetooth/esp_a2dp.html#_CPPv426esp_a2d_connection_state_t
void connection_state_changed(esp_a2d_connection_state_t state, void* ptr) {
    Serial.println(a2dp_sink.to_str(state));
    
}

// for esp_a2d_audio_state_t see https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/bluetooth/esp_a2dp.html#_CPPv421esp_a2d_audio_state_t
void audio_state_changed(esp_a2d_audio_state_t state, void* ptr) {
    Serial.println(a2dp_sink.to_str(state));
}

void setup() {
    Serial.begin(115200);
   
    pinMode(Relay, OUTPUT); 
    const i2s_config_t i2s_config = {
        .mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_TX | I2S_MODE_DAC_BUILT_IN),
        .sample_rate = 44100, // corrected by info from bluetooth
        .bits_per_sample = (i2s_bits_per_sample_t)16, /* the DAC module will only take the 8bits from MSB */
        .channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT,
        .communication_format = (i2s_comm_format_t)I2S_COMM_FORMAT_STAND_MSB,
        .intr_alloc_flags = 0, // default interrupt priority
        .dma_buf_count = 8,
        .dma_buf_len = 64,
        .use_apll = false
    };

    a2dp_sink.set_i2s_config(i2s_config);
    a2dp_sink.set_on_volumechange(volumeChanged);
    a2dp_sink.set_on_connection_state_changed(connection_state_changed);
    a2dp_sink.set_on_audio_state_changed(audio_state_changed);
    a2dp_sink.start("vMicro BT Speaker");
}



void loop() {
  
}
2

Investigate and discover what loop usually is used for.
Fiddling with a phone and it's hard to view the code properly. Better conditions here 12 hours later....

3

I found a solution, by replacing these lines it allows me to turn a digital output on and off when music is playing

void audio_state_changed(esp_a2d_audio_state_t state, void* ptr) {
    Serial.println(a2dp_sink.to_str(state));
    if (a2dp_sink.to_str(state) == "Started") {digitalWrite(ledPin, HIGH);}
    else if (a2dp_sink.to_str(state) == "Suspended") {digitalWrite(ledPin, LOW);}
    else if (a2dp_sink.to_str(state) == "Stopped") {digitalWrite(ledPin, LOW);}
    else if (a2dp_sink.to_str(state) == "Disconnected") {digitalWrite(ledPin, LOW);}