I am making a midi controller with 32 turn knobs/potentiometers. In the final circuit, I will read the 32 pots using 2x 74HC4067 boards (analog multiplexers with each 16 analog in/outs) connected to an Arduino Nano.
In the current circuit I have connected all 'ground' pins of the 32 pots to a common ground wire, and all the '5v' pins to a common 5V wire. The circuit with only 3 of the 32 potentiometers is:
When I read the various wiper pins (not connected to 5V or GND) I get strange results. For the first 75% of the knob turn, the resistance at each wiper pin increased, and turning further it decreases.
I have mixed potentiometers of different types (linear and logarithmic) and of different values (50k, 100k and 250k). Does this cause this strange behaviour?
Also I don't want to draw too much current for the 74HC4067, if I read specs correctly this should be max 50mA. Are pots > 5k safe? Is 250k too much?