[sdiy] Small Resistors and slider pots

[sasami at blaze.net.au]

I've seen similar things, and quite long too. They were 
retro-fitted to tool-making machinery to give digital 
readouts of various axis. Perhaps the regular electronics 
market is the wrong place to be looking for them. Try 
industrial suppliers instead.

Ken

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>At 07:23 PM 4/3/01 , The Peasant wrote:
>
>>Somebody needs to design an optical slide pot that tracks 
your finger position
>>and outputs a cv or whatever based on relative motion of 
that position. 
>>Shouldn't
>>be all that difficult...
>
>A long, long time ago, I saw an optical potentiometer in a 
catalog. It was
>a linear, or "slider", style of potentiometer. The unit 
contained two
>tapered strips of CdS, or similar photoresistive material. 
A beam of light
>was moved from one end of the sensor to the other to vary 
the resistance of
>the two elements. The elements were inversely arranged such 
that when one
>element had low resistance, the other had high resistance. 
I've never
>actually seen one of these in person, and I think the only 
time I saw it in
>a catalog, it was a "close-out" item, and soon to be 
discontinued.
>
>Has anyone on the list seen anything like I'm trying to 
describe?
>
>Later,
>Glen