Does anyone have technical drawings or such to explain how the outside wheel of the Nest thermostat works? I want to make something like it, but I’m not quite sure how the mechanics of it works.
the outside ring is a mutli function ring, basically you need to see if it’s turning clock or counter clockwise, then depending on which part of the UI you’re in it’ll have a different function.
Check this post as it may save you some time:
I think you misunderstood, I actually want to make a hardware unit like the Nest thermostat. Hence why I put it in the Hardware category 
lol then sorry I can’t help, I only do software
All I know about the Nest wheel thing is what I got from 15 seconds of video on their website just now. But wouldn’t you just use a toothed surface on the inside of the outer wheel, engaging a gear wheel on a rotary encoder?
Sounds like a great project