On my amp, I have a big round knob, that I can turn forever in both directions, to control volume.
It simply turns up whenever I turn clockwise and down when I turn counter clockwise. There is no limit as to how far I can keep turning it.
How do I create this in my own project?
I have an arduino where I want a knob like this, to control a value in the arduino memory. Simply, turning up, add to value, turning down, subtract from value.
I assume I need some kind of potentiometer, but they do not turn forever, do they?
Best Answer
What you need in a rotary encoder, they have two outputs that generate pulses which are then decoded to read the direction of rotation.
Refer to http://playground.arduino.cc/Main/RotaryEncoders
To control the volume you can use Arduino to drive a volume control chip like PGA2311.
There are even 4 channel versions like PGA4311
You can also control digital potentiometers like MCP41xxx/42xxx