SlightHeadache / choctopus44

Choctopus44 is a custom low profile keyboard

Choctopus44

Current version: 2.0

Choctopus44 is low profile, Choc spaced, optionally hotswappaple 44-key column staggered keyboard with a rotary encoder. It is loosely based on gtips's REVIUNG project, specifically REVIUNG41, but has deviated from it significantly during its development.

Known issues with v2

While all the main issues of the original Choctopus44 prototypes were addressed during the development of v2, some new minor arose during it's development.

• Switch plate does not accommodate all encoders properly. Certain non-Alps THD encoders, and SMD encoders may require filing the plate's encoder cut out to be a little bigger. See encoder documentation.
• Flaky Bluetooth behaviour in certain edge cases while using Nice!Nano, seems like certain devices don't like Nice!Nano's/ZMK's Bluetooth handling
• During fabrication with tented vias the battery circuit vias can easily remain exposed, at least with JLCPCB. By my understanding this is caused by the solder mask liquid seeping into the via's hole. This doesn't seem to affect other vias as only the battery vias are slightly larger than usual. This should be avoidable by using plugged vias instead, but as that increases the cost of manufacturing I'm going to create a hotfix version in the future that shrinks those vias to the standard size to alleviate the issue.

TODO

• Add documentation for v2's plate and bottom foams

Parts list

Main components

Part	Count	Optional	Notes
PCB	1
Diode [1N4148 SMD or THD]	45
Kailh Choc sockets	44	x
Tactile switch TL3342 or compatible	1		Stem height of 1.54mm used in tested builds
Slide switch PCM12 or compatible	1	x	Only useful if a wireless microcontroller is used in conjunction with a battery
EC11 encoder or compatible	1	x	See detailed encoder documentation; Can also be replaced with a Choc or an MX switch
ProMicro/Nice!Nano or compatible	1
MCU socket (or header rows)	1 (2)	x
Kailh Choc key switch	44 (45)
3.7 Volt battery	1	x	Only useful if a wireless microcontroller is used
100 nF capacitors (axial or 1206 SMD)	2	x	Used in the optional encoder filter circuit
10 kOhm resistors (axial or 1206 SMD)	4	x	Not adviced! Can be used in the encoder filter circuit, but can cause issues at least with Nice!Nanos

Case hardware

Part	Count	Optional	Notes
Top plate [PCB]	1
Bottom plate [PCB]	1
M2 stand off 5mm	9
M2 screw 3mm	15 (18)		18 needed if MCU cover is not used
Rubber bump ons	~11		Depending on your bump ons you might need to use more, or get away with using fewer

Example extra case hardware if using MCU cover

Note: The length of the required MCU cover stand-offs is highly dependant on the used battery and its orientation (assuming one is used at all), and the used MCU socket. With the listed screws and stand offs, a 5mm thick battery can fit between the MCU and the MCU cover without much issue as long as the the MCU socket is slim enough.

Part	Count	Optional	Notes
M2 stand off 10mm	3
M2 screw 10mm	3		Used for the bottom plate stand offs; 3mm screws used on the MCU cover

Misc hardware

Part	Count	Optional	Notes
Choc spacing compatible keycaps (e.g. MBK)	44 (45)

Firmware

Please note! Should you utilize a pre-existing QMK/Vial/ZMK set up, you may need to do additional steps not defined here before you can succesfully build the firmware. Whether or not that's required is highly dependant on the version and the state of your pre-existing set up!

Pre-built binaries TBA

• QMK: https://github.com/SlightHeadache/qmk_firmware : branch choctopus_project
  • If you want to utilize your existing QMK set up, navigate to it and run the following bash command to fetch and switch to the WIP branch. If you are using git via PowerShell or Windows CMD, remember to switch the &&s to semicolons. Remember to switch to your preferred local branch if you wish to meddle with other keyboards.

    git remote add choctopus_project [e-mail]:SlightHeadache/qmk_firmware.git && git fetch choctopus_project && git checkout --track -b choctopus_project choctopus_project/choctopus_project

• Vial: https://github.com/SlightHeadache/vial-qmk : branch choctopus44-vial
  • If you want to utilize your existing Vial set up, navigate to it and run the following bash command to fetch and switch to the WIP branch. If you are using git via PowerShell or Windows CMD, remember to switch the &&s to semicolons. Remember to switch to your preferred local branch if you wish to meddle with other keyboards.

    git remote add choctopus44-vial [e-mail]:SlightHeadache/vial-qmk.git && git fetch choctopus44-vial && git checkout --track -b choctopus44-vial choctopus44-vial/choctopus44-vial

• ZMK: https://github.com/SlightHeadache/zmk : branch choctopus44
  • For an easy online build using GitHub actions, fork https://github.com/SlightHeadache/zmk-config and enable Actions from Settings -> Actions -> Allow all actions. Then clone your fork. The keymap file can be found from path config/boards/shields/choctopus44/choctopus44.keymap in the cloned repo. The firmware should now build automagically when you push your keymap changes to GitHub. The built firmware can be found from under the GitHub Actions run's summary (e.g. https://github.com/SlightHeadache/zmk-config/actions/runs/6002979887), not under either of the build steps.
  • If you want to utilize your existing ZMK set up, navigate to it and run the following bash command to fetch and switch to the WIP branch. If you are using git via PowerShell or Windows CMD, remember to switch the &&s to semicolons. Remember to switch to your preferred local branch if you wish to meddle with other keyboards.

    git remote add choctopus44 [e-mail]:SlightHeadache/zmk.git && git fetch choctopus44 && git checkout --track -b choctopus44 choctopus44/choctopus44

Build guide

See build guide.