Features

• 36 key layout
• reversible PCB (same PCB for left and right side)
• hot swap sockets
• rp2040 zero
• 3D printed case
• 4P4C cable to connect the halfs

Parts

• 2 x PCB (~20 USD for 5 at JLCPCB)
• 2 x RP2040 zero
• female headers (the case is designed for headers with a height of 4 mm)
• 36 x SMD diode
• 36 x MX style switch
• 36 x hotswap socket
• 36 x keycap
• 2 x 4P4C jack
• 4P4C cable
• 3D printed case
• 14 x M2 hex nut
• 14 x M2 screw with a length of 5 mm

Used Software

• KiCad 9.x
• OpenSCAD
• Python

Printing the Case with Prusa Slicer

The print needs to be paused midway to insert the M2 nuts.

• tick Avoid crossing perimeters to reduce stringing
• tick Enable ironing to get a nicer finish
• Replace the contents of Printer Settings -> Custom G-code -> Pause Print G-code with the following to compensate for the filament that oozes out during the pause. (this works well on the Prusa mini but likely has to be tweaked for other printers)

M601
G1 X180 Y0 E1 F1000
G1 X150 E8.0 F1000

• slice and find the first layer that closes up the cavity for the M2 nuts
• right click on the plus symbol on the layer slider and click on Add pause print

QMK

https://github.com/johannesneyer/qmk_firmware/tree/master/keyboards/johannes_split

Compile Keymap from QMK Configurator

Import keyboards/johannes_split/keymaps/miryoku/configurator.json on https://config.qmk.fm edit and re-export.

qmk json2c -o keyboards/johannes_split/keymaps/miryoku/{keymap.c,configurator.json}
qmk compile -km miryoku -kb johannes_split

Flash

sleep 5 && \
  udisksctl mount -b /dev/disk/by-label/RPI-RP2 && \
  qmk flash -km miryoku -kb johannes_split
# enter bootloader on rp2040 now

Left / Right Configuration

Run the respective command for the left / right side.

qmk flash -km miryoku -kb johannes_split -bl uf2-split-right
qmk flash -km miryoku -kb johannes_split -bl uf2-split-left