Some things I'd like to see in the trackball:
1. "stick up" a bit more from the surface. This also makes it easier to "twist"
2. having the option to actually detect twists would be great. You can use it for scrolling or whatever.
3. I think having a heavier ball would work out better here in a lower friction environment, especially with a high DPI sensor.
1: Agreed. This is one reason I'm trying to find a DT225 to buy instead of a CST!
2: I agree with this, but it does present some new challenges*.
3: I imagine this trackball using a super arimath billiard ball for this reason.
A very dense trackball on very low friction bearings would be great, if it could be done in a reasonably cheap way, without too much required maintenance of the ball or bearings. (By reasonably cheap I mean, the mechanical parts assembled DIY for, say, <$50 or at the outside <$100.)
With out a large group buy this trackbal wouldn't be on the cheap side:
-30 dollars for the bearings
-17 dollars for the billiard ball
-30 to 80 dollars for a laser mouse*
-Who knows how much for a 3D printed housing
I wish you luck in your device of evil, just the same. What could be cool, though, is if you could post enough, like sensor firmware sourcecode, that were a different housing manufactured, someone like me who can't code his way out of a paper bag, could consider building a durable thumb trackball.
Its still going to get gummed up and need periodic cleaning, though. No way around that unless you add a high-pressure oil scraper ring so the part of the human-operated ball touching the ball bearings is always pristine.
No one is perfect, unfortunately!
I know zero code. Most of my knowledge is book-smarts and theory, with dabbling in graphic arts. As long as the sensor is positioned the same and the buttons are wired appropriately a different firmware shouldn't be needed for a thumb ball design.
Concerning cleaning, I emailed the bearing manufacturer for information concerning the potential for the bearings to gum up, if they are able to be cleaned, etc.
*If we were to use the guts of a standard laser mouse I do not think it'd be possible to register twisting as a scroll movement or what have you. The only way this'd be possible would be to create our own controller. To my limited knowledge, this'd involve the following (Again, prices are non-group buy):
-Purchasing this for use as the laser sensor:
https://www.tindie.com/products/jkicklighter/adns-9800-optical-laser-sensor/ (30 USD)
-Purchasing a Teensy USB controller (20 USD)
-Scavenging a cheap mouse for switches & wire.
-Finding an individual(s) who would be willing to write custom code for this that'd work on linux, windows, and mac (I use Windows) either for free or for a modest fee (the latter option would require a kickstarter I'd wager).
If we chose this path, the cost for parts minus the cost for a 3D printed housing and code would probably be around 90 to 100 USD (non group-buy prices).