impedance matching to mechanical sensors?
I agree with Scott Seidman in his comments here, I think the easiest way is to just use a buffer with general purpose op-amps to provide extremely high input impedance. The input input impedance will allow you to detect the voltage given out by the various potentiometer's wipers, without affecting the circuit by having any other loads in parallel. 

It does not matter what the resistance of the potentiometer used is, if you are only interested in the wiper's variable voltage output between 0 - 100% (which is probably what you are doing). 

Shown below is a non-inverting voltage follow/buffer, and the series 1K resistor is to help limit input current if something goes wrong on the potentiometer. You may want to throw a few low value capacitors in there too, to help with noise immunity. The value R2 being 10K is just arbitrary, to reduce overall power consumption but depends on your ADC's preferred input impedance.







simulate this circuit &ndash; Schematic created using CircuitLab