Toy/barebones synthesizer + audio output module

[jkominek]

A sort of pie-in-the-sky idea, that isn't part of any milestone, or blocking anything:

A board, conforming to the overall I2C/Qwiic scheme, which presents itself like the I2C UART on the MIDI output board, basically taking a stream of MIDI data written to register 0x00. But instead of streaming that MIDI data elsewhere, it runs it through a simple synth, generating an analog signal, and feeding it to any of line outs, headphone amps, or power amps for real speakers.

I don't have any interest in trying to implement even a sample-based piano synth in hardware, let alone a fancier synth than that. But some simple 32 voice sine wave + some harmonics that responds to note on velocities, note off, and sustain pedal could maybe be useful? I'm imagining a situation where you've taken a unit to a tech for them to work on the regulation of the system after confirming that whatever your issue is, is present even when using this simple synth.

It would also serve as a reference for anyone who wanted to build a more advanced synth. For instance, it is possible to get a Raspberry Pi to act as an I2C slave device. So, you could make a board that brings in the Qwiic connection, has plugs for a Raspberry Pi compute module (both for it to mount, and so you can put a display/keyboard/mouse on it), takes the audio output from the module, runs it through amps. Then you could slap Pianoteq on the Pi module, and have a largely standalone system with "real" synthesis and "real" audio.