I've made a little stop in zynthian software development and have finished a little project that has been over my desktop from a few months ago. Here is the result:
It's a simple MIDI-USB controller with 8 rotary encoders with led-ring, controlled by an Arduino-like board: the SparkFun ATmega32U4.
The firmware allows to control upto 24 MIDI-CC parameters arranged in 3 layers: red, green, blue. You can change the layer by clicking the top-left encoder.
The next step is fully integrating the controller with the Zynthian Box, so it can read the parameter values when loading a preset, for instance
You can find the schemes for the case and the firmware in github:
I will try to write a building tutorial in the next weeks.