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Corne V4

The Corne V4, this latest iteration of foostan's iconic split, comes with on-board MCU.
Published March 29, 2024
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Kosuke Adachi aka foostan published his new Corne V4 PCBs, both MX and the most recent Choc variants.

I don't think this iconic split keyboard needs an introduction. The Corne or Crkbd, originally based on the Helix and MiniDox, is a 3x6 (or 3x5) column staggered split which has inspired many other designs during its 6 years in existence.

Version 4 is PCBA-ready via on-board RP2040 MCU, and offers some new layout variants given you can put a display, extra keys or encoders in the inner columns.

I intentionally abandoned backward compatibility to achieve technological advancement and design updates. Changes include fine-tuning the key pitch, MCU alteration, TRRS jack and LED design improvements, the addition of expansion options, and the introduction of a new dedicated case – foostan.

V4 specs

  • 42-46 keys (3x6 or 3x5 split layout, 3 thumb keys)
  • MX or Choc (different PCBs)
  • hotswap (soldered version will be released later)
  • snap-off outer column
  • on-board RP2040 MCU
  • USB-C connector
  • optional inner rotary encoders or extra keys
  • optional display
  • per-key RGB


Major design changes (from v3)

  • Change in pitch: from 19mm to 19.05mm
  • Departure from Pro Micro: RP2040 on the PCB
  • Change in TRRS jack parts
  • No more underglow: for cost reduction and simplification


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Published on Fri 29th Mar 2024. Featured in KBD #160.


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