This board is designed to be modular, with a bare-minimum configuration and some options to add if needed, with additional modules.
For the bare-minimum configuration, the board will have 2x TFA9879/TFA8200 amplifiers onboard (in this case they are equivalent). Those are nice and cheap 5V digital amplifiers with DSP inside and driver already available in mainline kernel. Together with the amplifiers, there will be 4 tactile switches and one RGB led, connected to GPIOs.
The additional modules that can be added to the board are the following (please google them, they are quite common):
- 0.96" I2C OLED DISPLAY MODULE 128X64 SSD1306
- Up to 2x INMP441 MEMS Omnidirectional Microphone Module I2S
Oled screen can be used to display some information using this library
tactile switches can be used for controlling playback, volume and/or shutdown, together with dedicated plugin
RGB led can be used for SD-card activity of for playback status, together with dedicated plugin
I2S Microphones will not be necessary for Volumio at the moment, but they can be used for other project (Google-assistant, Alexa-assistant, voice-triggered in general). I really hope it will be possible to control Volumio with voice commands in the future, so I made the design ready for that.
I will release complete source code and all the necessary files for producing the assembled board from PCB manufacturers. PCBWAY has a running promotion with 30$ assembly fee and free DHL shipping up to 20 pieces. Modules can be added manually or by the manufacturer, upon request.
I will also release some scripts for using the board with Volumio and Raspbian, hopefully I will find someone willing to help for creating a dedicated dt-overlay and make use of the HW mixer, HW EQ and HW DRC (Dinamic Range Compressor).