ADNS5050 VS trackball

Which library are you using? https://github.com/okhiroyuki/ADNS5050?

Link to the data sheet: https://media.digikey.com/pdf/Data%20Sheets/Avago%20PDFs/ADNS-5050.pdf Link the the library: https://github.com/okhiroyuki/ADNS5050

Looks like this project hasn't been updated in a while. But you can try this for a library to use. https://github.com/okhiroyuki/ADNS5050

Currently, it has a polling rate of 1,660Hz. This isn't really indicative of the final performance as its very barebones. Most of the firmware is from this Github repo.

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