kb3 - OpenSCAD 3D printable keyboard with TKL layout

I was inspired by the SiCK-68 keyboard on thingiverse, but I favor the tenkeyless layout. In particular, switching between the SiCK-68 and a TKL is difficult because of the compromise in placement of the escape key. I realized that with a similar "two halves" design, I could print a full tenkeyless layout on my printer, but just barely. That's when I started my own 3d printable keyboard design in OpenSCAD.

Mechanicals

Aperture sizes are taken from direct measurements, from mechanical drawings of Cherry MX and Kailh keyswitches, and from the excellent (if somewhat bitrotted) kad program. The stabilizer openings are for "Keystar" style stabilizers.

In contrast to SiCK-68, the case halves are joined with M3 screws into heat-set inserts. Internal electronics are mounted via threaded inserts or little brackets, as appropriate. A panel-mount USB connector is used, instead of situating the main microcontroller PCB at a fixed location.

Electronics

This isn't done yet :) The tenkeyless layout needs 23 I/Os for the "obvious" but inefficient matrix. This can be dropped by 1 column pretty easily, allowing one pin left over on an Itsy Bitsy (M4, M0, or AVR 32u4, not the upcoming nRF52840)

Software

I plan to run CircuitPython, which will mean a need for new code. CircuitPython can do basic HID (USB and Bluetooth). However, as far as I've discovered, there aren't any libraries on top of that to facilitate keyboard layers, etc.

OpenSCAD structure

cherryplate.scad functions as a library, and tkl.scad creates a particular keyboard.

Status

See the issues page for items I know need to be worked on.

I think the 3D parts are complete.

Contributing

I'm not sure this is ready for contributions or even issue reports yet.
That said, stuff that would be great to do is:

• Refactor cherryplate.scad so it is a good basis for further work
• Pull items such as alignment pin locations into cherryplate.scad
• Maybe an (external, Python or such) converter from www.keyboard-layout-editor.com layouts to my internal format
• Contribute other layouts

Bill of Material

This bill of material is a work in progress. Verify it yourself, don't order blindly

(These are not affiliate links, but I do work for Adafruit)

Item	Qty	Link	Comments
Filament	~400g		I used PLA
Keyswitches	87		I'm using Kailh Purple
Costar Plate Mounted Clips	2 * 5	https://www.wasdkeyboards.com/cherry-mx-plate-mounted-stabilizer-clips-2pcs.html
Costar Keycap Stabilizer Insert	2 * 5	https://www.wasdkeyboards.com/cherry-mx-keycap-stabilizer-insert-2pcs.html
Costar Stabilizer Spring for 2x+ Keycaps	4 * 5	https://www.wasdkeyboards.com/cherry-mx-stabilizer-spring-for-2x-keycaps.html
Costar Stabilizer Spring for Spacebar	1	https://www.wasdkeyboards.com/cherry-mx-stabilizer-spring-for-spacebar.html
M3 x 4mm threaded inserts	12	https://www.mcmaster.com/94459A130
M2 x 2.5mm threaded inserts	12	https://www.mcmaster.com/94459A110
M3 x 8 screws	12
M2 x 6 screws	8
Neopixel strips	4	https://www.adafruit.com/product/1426
Itsy Bitsy M4 Express	1	https://www.adafruit.com/product/3800	Or 32u4 or M0
panel mount micro USB connector	1	https://www.adafruit.com/product/3258
Wiring