This design was introduced when Karl experienced difficulty in acquiring the correct linear pots. Most of the ones are logarithmic instead of linear scale, resulting in an incorrect reporting output to the sim.
 
Karl redesigned the complete unit based on a rack and pinion assembly. It still has the working friction unit.
 
This is only the CAD files! Not STL or build guide right now. Once Karl gets a chance he will create STL's and a build guide for this product.