GitHub - notaroomba/keybytes: A truly modular keyboard

A truly modular keyboard with rearrangeable keys, magnetic cases and Bluetooth!

Key Features • Video Demo • PCB • Case • Credits • License

Video Demo

keybytes-demo.mp4

Key Features

Rearrangeable layout where every key is its own 1u PCB
CH32V003 RISC-V microcontroller on every key
STM32WB55RGV6 main board with Bluetooth and USB
Pogo pins on all 4 sides of every key for power and I2C
Magnetic cases to hold the modules together
Key programming from the main board over pogo pins
2MB QSPI flash (W25Q16JV) to store the key firmware
Battery charging with the BQ25895 and solder pads for a 1S LiPo
Buck-Boost converter (TPS631000)
RGB status LED
USB-C with ESD protection
Ceramic Bluetooth antenna

PCB

Designed in KiCad! There are two boards, the Keybit and the Keyword, and both are 1u (19.05mm x 19.05mm).

Keybit

A single key with a Cherry MX switch and a CH32V003. Every side has pogo pins for 3.3V, GND and I2C so it can connect to the keyword or to other keybits, and the pads on the corners are for programming.

Schematic:

Layout:

Keyword

The main board that the keybits connect to. It is split into two PCBs that stack on top of each other. The top one has the STM32WB55RGV6, the antenna and the flash, and the bottom one has the USB-C, the charger and the buck-boost converter. The 3 pogo pins on the top are for programming the keybits.

Schematic: