[map32] Audio Player

[Mischback]

The actual core component of the project.

Crucial Dependency

• evaluate available hardware
  • SD card reader (https://www.adafruit.com/product/4682)
  • DAC
    • I2S DAC&Amp (mono): https://www.adafruit.com/product/3006 (two of them can be used to actually get stereo (some circuit-magic involved!))
  • Amplifier
    • https://www.adafruit.com/product/987 (has to be driven by the internal DAC of ESP32 board, which (as found on the internet) introduces lots of noise) available in hardware, not for the first implementation
• modify development board to support these
  • documentation(!) (KiCAD? Should these be part of the repository?)
  • is a hardware description (HAL) required to use ESP-ADF?

Functionality

• play mp3 from web stream
• play mp3 from SD card
• play mp3 from NAS
• control player with specific commands (see mnet32's task)
  • play/pause
  • next/prev
  • volume up/down
• include web interface for the audio player component
  • hooking into the existing minimal httpd
  • minimal interface
  • see Web Interface #7
• play mp3 from connected bluetooth device?
  • highly optional
  • Is WiFi and Bluetooth working in parallel?
  • Is it possible to apply play/pause and next/prev controls to the connected bluetooth device?
  • Is this even a shared codebase or seperate functionality? If so, should the be combined into one component or be provided by dedicated components?
  • https://github.com/pschatzmann/ESP32-A2DP
  • https://github.com/espressif/esp-idf/tree/master/examples/bluetooth/bluedroid/classic_bt/a2dp_sink