Kagu

Kagu

A wireless 36-key split keyboard (3x5+3) on the Seeed XIAO nRF52840, running ZMK.

• keymap.txt: the keymap, the only file to edit for layout changes
• keymap/: the generator that turns it into ZMK, and the diagram
• config/: ZMK shields and the generated kagu.keymap
• pcb/: KiCad projects for both halves
• case/: OpenSCAD trays, top plates and Choc v2 keycap risers

Layout

Colemak-DH, after dubu36. Shortcut modifiers sit on the home row (pinky to index: Shift, Ctrl, Alt, Super, mirrored). Shift and the layers you use while writing sit on the thumbs, which keeps hold-tap timing out of the way. Some notes on the layers:

• rse: numbers on the left, navigation on the right. lwr: symbols.
• app and os: held from C and , (app) or D and H (os). They keep Ctrl or Super down for the whole hold, so every key is sent with that modifier, including the arrows on U N E I.
• sys: Bluetooth profiles, held from Z or /.
• mou: held from X. Left-hand Ctrl+Q W S T Z C V for when the right hand is on the mouse.
• hyp: held from the right outer thumb. Every key is sent with Ctrl+Alt+Shift+Super, for niri bindings. The HYP_[ HYP_\ HYP_] keys on rse send the same.
• Combos: W+F types Esc, and U+Y types Enter.

Editing the keymap

Each layer is a grid of the 36 keys, laid out as they sit on the board: three rows of ten, then the six thumbs.

layer base: left_mods, right_mods
  Q      W        F      P     B          J        L     U      Y     '
  A      R        S      T     G          M        N     E      I     O
  Z/sys  X/mou    C/app  D/os  V          K        H/os  ,/app  .     \//sys
                  BSPC   LSHFT/LSHFT  lwr/lwr     rse/rse  SPC   _/hyp

  Z/sys         tap Z, hold the sys layer
  T/LGUI:hm     tap T, hold Super, as a positional home-row mod
  LSHFT/LSHFT   one-shot Shift on tap, plain Shift on hold
  _ / TRNS      nothing / fall through to the layer below

Holds shared by several layers are written once as an overlay and listed after the layer name. layer app + LCTRL holds Ctrl for as long as the layer is held. Combos are written W F -> ESC. The header of keymap.txt covers the details.

After editing, run just keymap in the Nix dev shell. It regenerates kagu.keymap and redraws the diagram with keymap-drawer. CI fails if kagu.keymap is out of date.

Keycaps

• 3dkeycap.com