Hi!
Started this thread after our discussions here @damianhl @markhh2 : Previous convos
After trying a handful of DACs, I found love with the Exogal Comet Plus. However, it's user interface.... barely exists. It has a small silver LCD screen that can be a bit difficult to read and is primarily controlled via a BT remote or a depreciated app (Android 9 or lower only). Either remote option can be unreliable at times, so I set out to create a better solution.
My idea was to use an Arduino to directly send the remote commands, removing the need for wireless shenanigans, or to use a Raspberry Pi to operate the DAC from a web portal. I probed the DAC Bluetooth chip output but hit a dead end. Thanks to Bob (from Exogal) backing up some dealer info, there is enough documentation to use the TTL serial port on the back for firmware updates. Huge help and starting point. I reached out to Jeff (also from Exogal) who was immensely helpful as well, and helped me get the ball rolling.
Turns out you can control the DAC via the serial port! Using a USB-to-serial adapter cable, I wrote an app that interfaces with Comet! Written in Python since it’s what I’m familiar with. It’s a simple button-based GUI app that currently allows you to select which COM port to use, power on/off, select input and output, mute/half-mute/unmute, increase/decrease volume, or enter a specific volume value. All through the desktop app!
But I want hardware. Ran out of pro micros so I grabbed a few $5 Raspberry Pi Pico micro controller boards to try. MircoPython is great! Videos of the prototypes:
So far I've got most of the code sorted between a rotary encoder and a display. More work to be done but progress feels good. I plan to use 2x of those displays since I have a few already: 1x for big font Input/Output/Power, the other for Volume/Mute. Next up is to add an IR receiver to handle desktop volume adjustment and living room IR remote use.
Huge thanks to Jeff, Bob, and others for helping keep this DAC alive and well. Not sure how many people care about this, but I'd like to share it with those that do. Been waiting on solutions like this for a long while - long enough to try to do it myself. Thanks!
