[JesseK]

Last year our team brought up using an extending lanyard ($3) with a multi-turn pot ($3) for this purpose on our elevator. We tried it with a lanyard and with a $2 tape measure.

The main issue with the lanyard is that the internal rotary 'spring' doesn't have enough force to turn the potentiometer when the string is almost all the way retracted back in. Repeated wear only exacerbates the problem. With a tape measure, no one axle 'rotates'...the entire spring and tape measure rotates as you pull it out. Hence the reason tape measures are always smooth and slippery against metal.