My third keyboard design: diode-free, 34-keys, Bluetooth, spilt

Back when I was first looking at DIY keyboard designs, one that caught my eye was the Forager - a cute little 34-key wireless split keyboard in a compact elegant case. I was ready to move down to 36-keys, but just 34 seemed a stretch (I'm willing to try now). Also, it looked like a challenging build - surface mounted hotswap sockets (I can do those now), two little Seeed XIAO controllers (should be OK), and 34 surface mounted diodes (tiny and daunting). Well, I could just design my own diode free keyboard PCB again, right? 

I actually did the initial PCB design for this while still finalizing the case modifications for my second keyboard, the Gamma Omega Hesse, and ordered the Acid PCB as the Hesse PCB was being shipped to me. Hence the meme.

No Logo Tech NRF52840 controller boards

It turns out that ProMicro footprint clone of the Nice!Nano v2 controller with 21 GPIOs (which I bought for my Hesse Bluetooth keyboard) is part of a family of at least four similar boards of differing sizes, possibly all originally from No Logo Tech. In English at least, the naming is rather confusing! The others expose even more GPIO pins (although many not on easily reached pins), and some have an RGB LED built in too. Sadly most are rather lacking in documentation outside of product listings on AliExpress and the like, but they have LiPo battery charging, and are all using the Nordic NRF52840 chip so ought to work with ZMK for use in a keyboard design.

"ProMicro NRF52840"

"Nano 33 BLE NRF52840"

(Xiao-like) "SuperNRF52840"

"Super mini NRF52840" (with space)

My second keyboard design: diode-free, 36-keys, Bluetooth

About three months ago I blogged about my first keyboard PCB design, a diode-free PCB for an existing 36-key ergonomic case. Since this summary of my journey into keyboard madness, I learnt how to write my own ZMK keyboard firmware, as a precursor to designing a version with Bluetooth. This time I also had to learn some basic CAD to modify the keyboard case. And here it is, the Gamma Omega "Hesse", a Bluetooth diode-free 36-key ergonomic keyboard.

Front & back of the "Hesse" keyboard PCB

Removing parts of a STEP file in FreeCAD

My first baby steps with FreeCAD for editing step files, the comparatively easy challenge of removing some block-like shapes in a 3D-printed keyboard case. The motivation here is making room for a battery & reset button for a Bluetooth variant of what was a USB wired-only keyboard. Getting started with FreeCAD is hard!

Before - note the bracing beams

After - now with lots of open space

Naginata Style (薙刀式) for typing in Japanese

Naginata Style (薙刀式), by author Toshihiko Ōoka (大岡俊彦), is a Japanese kana-based keyboard layout which caught my interest. It was developed to work on traditional keyboards with spacebar used as central shift, but also works well on small ergonomic keyboards with thumbs-keys. The most common kana are a single key press, but generalising the idea of shift keys any other kana requiries a two-key combo (including compounds like "きゃ" or "kya"), or at most a three key combo (compounds like "ぎゃ" or "gya" with a ten-ten modifier). The layout is more ergonomic than Qwerty and the rarely used JIS Kana layout, and needs less key presses than romaji.