I have a CODEC circuit with a AUX audio output. Is it possible to connect that output back to the ESP32 and transmit to a Bluetooth speaker using the ESP32-A2DP library?
If so, would this be the bones of the program:
/*
Streaming of sound data with Bluetooth to other Bluetooth device.
We generate 2 tones which will be sent to the 2 channels.
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/>.
*/
#include "BluetoothA2DPSource.h"
#include <math.h>
#define c3_frequency 130.81
BluetoothA2DPSource a2dp_source;
// The supported audio codec in ESP32 A2DP is SBC. SBC audio stream is encoded
// from PCM data normally formatted as 44.1kHz sampling rate, two-channel 16-bit sample data
int32_t get_data_frames(Frame *frame, int32_t frame_count) {
static float m_time = 0.0;
float m_amplitude = 10000.0; // -32,768 to 32,767
float m_deltaTime = 1.0 / 44100.0;
float m_phase = 0.0;
float pi_2 = PI * 2.0;
// fill the channel data
for (int sample = 0; sample < frame_count; ++sample) {
float angle = pi_2 * c3_frequency * m_time + m_phase;
frame[sample].channel1 = m_amplitude * sin(angle);
frame[sample].channel2 = frame[sample].channel1;
m_time += m_deltaTime;
}
return frame_count;
}
void setup() {
//a2dp_source.set_auto_reconnect(false);
a2dp_source.start("LEXON MINO L", get_data_frames);
a2dp_source.set_volume(30);
}
void loop() {
// to prevent watchdog in release > 1.0.6
delay(10);
}
https://github.com/pschatzmann/ESP32-A2DP/blob/main/examples/bt_music_sender/bt_music_sender.ino
Right now, as a proof of concept, I just bought an off the shelf Bluetooth transmitter:
So, I want to get rid of the off the shelf Bluetooth transmitter to hopefully feed the audio into the ESP32 to transmit instead.
