Implement rotary switch, toggle switch and potentiometers with Arduino to simulate keyboard press
Some solutions that I did implement:


I did connect resistors between each pole of the rotary switch, up to the last one, skipping only the common pole for obvious reasons. Then I connected the first notch to positive, the last notch to negative and the common pin to one of the analog input of the controller; so when I read the values; I get finite steps between each notch; and as such, I can implement the various increase and decrease values that I need.
The toggle switch has been implemented as matrix; so I use 2 pins for each of them, and watch for the hold and release state, to figure out what to do.
The potentiometer was implemented as analog axis directly in the microcontroller; straightforward data read from the analog input, with a bit of normalization to avoid fluctuation.