Acceleration comparisons

[RPS69]

There are commercial potentiometers, that allow you to turn around 10 times, and have a numerical track of your position.
They are very precise, and can move fast if well kept. Still, don't play unneadlessly with them, because they get noisy after so many changes. Still, they may work fine for around 10 years on an everyday use.

http://www.schukat.com/schukat/schuk...8&kb=DIAL15111

That was the first example I stumbled upon. Don't know how good they are though...