KeySeeBee is a split ergo keyboard. It is only 2 PCB (so the name) with (almost) only SMD components on it. It's only a keyboard, no LED, no display, nothing more than keys and USB.

The firmware is Keyberon, a pure rust firmware.

• 44 keys, using Cherry MX or Kailh choc switches, only 1U keycaps;
• USB-C connector on the 2 sides;
• TRRS cable for connecting the 2 halves (for power and UART communication between the 2 halves);
• 2 STM32F072 MCU, with hardware USB DFU bootloader and crystal less USB;
• Only onboard SMD component (except for the switches and TRRS connector).

• Plaid for "show the components"
• GergoPlex for "just a keyboard" and "only a PCB with SMD components"
• Lily58 for the thumb cluster
• Kyria for "don't be affraid of pinky stagger"

Price is for 5 keyboards including shipping.

About 60€ without switches, keycaps and cables for 5 keyboards (12€/keyboard).

Install the complete toolchain and utils:

curl https://sh.rustup.rs -sSf | sh
rustup target add thumbv6m-none-eabi
rustup component add llvm-tools-preview
cargo install cargo-binutils
sudo apt-get install dfu-util

Compile:

cd firmware
cargo objcopy --bin keyseebee --release -- -O binary keyseebee.bin

To flash using dfu-util, first put the board in dfu mode by pressing BOOT, pressing and releasing RESET and releasing BOOT. Then:

dfu-util -d 0483:df11 -a 0 -s 0x08000000:leave -D keyseebee.bin

The fist time, if the write fail, your flash might be protected. To unprotect:

dfu-util -d 0483:df11 -a 0 -s 0x08000000:force:unprotect -D keyseebee.bin