Keyboard Builders' Digest / Projects
Cirrus40
A 36-key split keyboard with rotary encoders and hardware debouncing: Cirrus40 by schuay.
Published March 23, 2026
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The Cirrus40 by Jakob Linke (aka schuay) is a 40% split mechanical keyboard, with focus on usable rotary encoders.
I got a bit fixated on encoder ergonomics and precision during my last few builds. The result is encoders positioned under the palms — reachable without moving your hands from homerow — paired with a hardware debouncing circuit on the PCB (RC filter on each encoder channel) so there are zero missed transitions. I strongly recommend ALPS EC11E15244G1 encoders to get the most out of it – schuay.
Meaning: the thumb and index finger move a bit and turn the encoders while keeping all other fingers on the home row.
According to Jakob, with homerow mods, one-handed encoder use opens up a lot: tab switching, workspace switching, word-by-word navigation/selection/deletion.
Features
- 36 keys (5x3+3)
- MX switches, hotswap
- Pro Micro footprint (e.g. Pro Micro RP2040 or nice!nano for wireless)
- reversible PCB
- EC11 rotary encoder
- 3D-printed case
- QMK/ZMK firmware
Resources
Published on Mon 23rd Mar 2026. Featured in KBD #209 (source).
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