[clug] O/T Digital Position sensing

Ben Nizette bn at niasdigital.com
Mon Nov 2 20:28:04 MST 2009

On Tue, 2009-11-03 at 11:11 +1100, Keith Goggin wrote:
> Could anyone recommend some light reading on Digital Position Sensing?
> I need to know the position of a shaft that can rotate through about 90 
> Degrees. I have tried a rather crude setup with a micro-switch but I 
> require something a little more sophisticated.

As mentioned elsewhere, optical encoders give you good resolution but
it's only a velocity thing.  You can integrate it to position but there
is then the probability of accumulated error if/when you miss readings.
The /simplest/ thing for absolute position I can think of given the
limited range is a potentiometer and ADC.

Do you have any other criteria regarding resolution, speed, mechanical
specs, acceptable load added to the shaft etc?  What are you using to
get this data out (pc, microcontroller etc)


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