[sdiy] Mod/Pitch Wheel Thoughts

[Ingo Debus]

Am Montag, 14.03.05 um 02:28 Uhr schrieb harrybissell:

> The flat area, with a single cell... is a loser.   The cells have a 
> really
> poor thermal stability, so changes in temperature render the optical
> flat useless.
>
> You might do differential illumination on a center-tapped cell... at 
> least the
> two halves would track.
>
> I think trying to null the center is too hard. I'm thinking "mod wheel 
> = good"
> "Pitch-wheel = bad"
>

How about a shutter where maximum light (or minimum, whichever is 
easier) is exposed to the cell in the center position of the wheel, and 
minimum (maximum respectively) at either end? It would need an 
additional switch that detects whether the wheel is moved up or down 
and reverses the polarity in one case. A flat area around the center 
position would be easy to implement.

Ingo