An hardware USB Scribble Strip that supports the Mackie Control Protocol.
µScribble is an USB Midi gadget designed to be a companion to inexpensive faderboxes without displays. It should be compatible with any DAW that supports control surfaces. I've personally used it with Apple Logic Pro and Ableton Live.
The hardware itself is very simple an d based around an STM32F4 evaluation board, sometimes known as "blackpill", while the displays are the SPI variant of the ubiquitous SSD1306 OLED screens.
The software is implemented using the unicore-mx fork of libopencm3 as it has a slighlty better support for the stm32 target platform. It should be relatively easy to port the application code to any microcontroller of choice.
The hardware is designed using the KiCad EDA
The firmware depends on the arm-none-eabi-gcc toolchain, and to compile it
it's sufficient to invoke
make
As a convenience, if you have the STLink
tools installed, you can flash the firmware to the device using the st-flash command
with
make flash