I'm making a project with an Arduino. I'm wanting to add a rotary control knob so that when I rotate it one way a variable increases and when I rotate it the other way it decreases. I'm not wanting to use a pot, I want to be able to rotate the knob more than one turn and still increment/decrement. I know that such things are available as I have something similar in the volume control on my car radio but I don't know the name of what I'm looking for, any ideas? Thanks!