Electronic – Choice of material for a cylindrical potentiometer

potentiometer

I want to sense position along a slightly curved metal rod (length 100mm, diameter 5mm) for a project. For the wiper element, I'll be using steel wire of diameter 0.3mm, the length of which runs perpendicularly along the rod's length. I've tried wire-wound techniques, but they pose issues for my project such as durability and a lack of surface smoothness. I'm thinking of creating a new rod with the same dimensions made out of a material that would be durable enough to withstand heavy usage. I was looking at carbon based plastic materials since they offer high resistance, but am open for advice. I want to be able to mould the material into the shape of the rod in question.

Is this a good way to go, and if yes, what material would suit best?

Best Answer

Consider:

  • electrically conductive 3d-printing PLA -- you could use it straight, or you could 3d-print the pieces. It's only "conductive" compared to normal plastic. It has a resistance of a few ohms per centimetre (but obviously depends entirely on shape)
  • nichrome wire -- such as often used in (unwound) electric guitar strings, used for heating
  • various other antistatic protection plastics

A search for conductive plastics found TECAPEEK, which looks like the kind of stuff you're after.

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