trackball VS dometyl-keyboard

I did lay out a simple carrier board as a direct replacement for the breadboard in a more permanent build, and had a few of them made up through OshPark. It's really basic -- no components, just some traces and solder pads. (My first time trying to use kicad, I think it turned out decent for what it is.)

not quite sure what you are getting at... regarding thumb use, you can always buy used FXes (or new ones if you want a crazy markup). if you want something slightly more modern, there is the cordless FX. the DIY trackball you speak of is publicly available here: https://github.com/monroewilliams/trackball

isnt a scan, but its a 3d printable trackball with roughly similar shape: https://github.com/monroewilliams/trackball

For me, the hand position used with the Logitech Trackman Marble FX was near perfect for reducing hand and wrist stress. Unfortunately that model was discontinued many years ago, and they're now hard to find, expensive, and generally antiquated (PS/2 interface, dodgy early optical sensor, no scroll wheel). This was the main reason I designed and built my own trackball. Its shape was inspired by the Marble FX, although I modeled it from scratch in OpenSCAD.

Of course. 😎

Sources for all the parts I used are listed here, and there's a fairly extensive assembly guide with pictures here.

For my scratch-built trackball project, I used these breakout boards, and based my initial code off of the seller's sample code. His sample is for Arduino. but it's basically pretty straightforward C code that isn't hard to adapt to any microcontroller. For my purposes I needed to run two of the sensors off one microcontroller, so I turned into a C++ class that runs one sensor per instance, and supports a couple different related sensors (ADNS9800 and PMW3360).

The ball-spin mousewheel is a really nice touch, too

This is a 34 key choc dactyl https://github.com/geoffder/dometyl-keyboard/tree/main/things/dartyl_choc

If you are fishing for something weirder, but still Topre, the Dometyl is a Dactyl offshoot that uses rubreh domehs and sliders. I have not tried it myself.

You could use domes. https://github.com/geoffder/dometyl-keyboard/ offers some technical advice and links to some products. Complex, and also expensive.

You're totally not crazy... or at least not alone in this! You may want to have a look at https://github.com/geoffder/dometyl-keyboard/

Try "skeletal" designs such as those from bastardkb.com or one generated from dometyl.

Firstly, please consider a Skeletyl instead of a conventional Dactyl. Skeletyl has a lot less material and so is a lot faster to print. If you need more than 5x3+3 keys, you can customize your own Skeletyl style case as well: https://github.com/geoffder/dometyl-keyboard

I made this guy https://github.com/geoffder/dometyl-keyboard/tree/main/things/dartyl_choc