Helvetica 'Foofers' Bold - Ah, bugger.

11:29 pm - Ah, bugger.

Okay, after much banging of head on desk, I think I figured out the problem.

Discovered in the fine print of the Apple developer documentation somewhere that whether or not a user-space application can address the outside I2C bus is entirely optional and at the whim of whomever implements the specific video driver, but with no clear outside indication. It just so happened that the first system I tested this stuff on permitted this (MacBook w/Intel GMA950 graphics) and that initial success led me down a path of irrational exuberance. Same code on the Apple TV, no such luck (NVIDIA GeForce Go 7300). My roommate’s current-generation iMac worked (ATI video), while my prior-generation did not (NVIDIA). Took a while before I noticed the pattern and correlated it with the initial fact.

This still has a great deal of usefulness for some specific things I want to do, and I’ll still write up about it because, c’mon, it’s a pretty funny hack. But the willy-nilly driver support does limit its general utility outside these walls, and I’m a bit bummed that it can’t work on the Apple TV, which really needed a set of mechanized spider legs, y’know?

Need to get caught up on some other projects, but I’ll come back to this later and see if and how the same capability exists in Linux…hopefully more uniformly regardless of the graphics card vendor. It’s the kind of thing that might appeal to the tinkery Linuxy Lego Mindstormsy sort of mindset…it’s just code, wire and cheap sensors then to put together a data-logging weather monitor or things like that. Then you just need a gray beard, suspenders, recumbent bicycle and subscription to Home Power magazine to complete the effect.