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