CHEAP or EASY String Pots (source, or fabbed)

[Alan Anderson]

Originally Posted by kmcclary

Rack and pinion pots won't easily fit there, and optical slides could get dirty. Without a rotational joint present, cheap pots won't work either.

Something equivalent to a 25" string pot (into our Analog Inputs) seems ideal, but it:
A) Needs to be CHEAP to make (no $100 commercial string pots!), and
B) Preferably can be assembled MOSTLY with COTS hardware store items, with as little machining as possible.

Try a "chain pot". Instead of string, use a length of #25 chain. Think of a flexible rack & pinion connected to the end of your slide, with the chain bending around a pot-equipped sprocket and having a tensioning spring at the far end.

With a large enough sprocket, you might even be able to get away with a single-turn pot (or a magnetic absolute position sensor).

What are you using to move the slide? If it's a chain, you're most of the way there already.