sounds like a hardware problem and would only be related to Xojo if/when you had hardware that interfaced to your computer via a USB or other type port. No software solution can be devised without knowing your interface parameters.
I need to clarify. I am trying to build a physical switchboard - something like a mixing board. Probably, I need to learn Raspberry Pi programming - how to read the status of the potentiometer and translate its value into a software parameter value.
I know that this could be done in Python, and I was wondering if XOJO could do it as well.