It's basically a Pi, a buck regulator, a tiny COB USB audio interface and an SSD1306-based 128x32 display. Removed all connectors and replaced them with soldered wires so it packs neatly into a tiny box.
The software is all custom and written in C, using Jack for low latency audio and my own driver for the display (Adafruit makes a Python driver but it eats half of your CPU and is not optimized for i2c bandwidth or high framerates).
The software is all custom and written in C, using Jack for low latency audio and my own driver for the display (Adafruit makes a Python driver but it eats half of your CPU and is not optimized for i2c bandwidth or high framerates).