[asid61]

Originally Posted by techhelpbb

String encoder?

Put a quadrature encoder on a badge holder pull out string assembly.
No noise floor, just a decoding issue which you can get electronics to solve like this:

http://www.avagotech.com/products/mo...r-ic/hctl-2022

The string encoder allows one to skip a lot of custom work and sense the distance directly, rather than going through extra layers like decoding encoder outputs. Not to mention that given the costs of shafts, bearings, machining, and the encoder itself, it might make more sense just to use the string pot.