I have a nested dial control on Android. It looks like this:-
The labels are a bit small to read on the screenshot: they're days, hours, mins. Note in particular that the read-out point is at the bottom.
I'm trying to make this control more generally useful by allowing it to be controlled with a D-pad or arrow keys, instead of a touch interface. I think each of the nested dials should be focused in turn, starting from the innermost "days" dial (because it has the largest effect, it's the one you'd expect to set first). Then pressing ↓ should take you to hours, etc. and ↑ back to days.
The question is about rotating each dial. Because the user is looking at the bottom of the dial, moving it to the left here means clockwise and increases the value, whereas usually we associate right with clockwise, and with increasing (if you're a left-to-right reader).
So which way should it rotate? Should → turn the dial clockwise, matching the right/clockwise/increase association, but making the numbers pass the readout point in the opposite direction; or should ← turn the dial clockwise, to match the leftward swipe gesture you'd do to turn the wheel? And whichever answer you prefer, how can I mitigate the confusion caused by the mismatched association?
P.S. I'm sure someone will ask why the readout point is at the bottom. It's for two reasons. First, it allows the days dial (the one with the fewest notches) to be on the inside, yet still the first in reading order. Second, users tend to be nearer the bottom of the screen than the top when using a hand-held. Putting the focus closer to the user supports the 3D illusion of the dial, whereas at the top the user feels like he's peering over the top of the dial to see it. I also experimented with having it at the right-hand side instead, to get around this problem, but having the numbers turned sideways looks incredibly confusing.