rotary switch / turn knob? how to call it?

Question

Im looking for a switch-like rotary knob, that i can turn left and right. Its outputs a simple 'pulse'. You find these in selecting/setting numbers on assorted electronics. You can keep turning them (both directions), there is no absolute '0' point. But i need to know, if you turn left or right.

Its for a simple Arduino project, i want this rotating know/switch to increase the number on a LCD (turning right) and decrease the number when turning left.

But whats the name ??

Thanks.

Answer 1

(Incremental) Rotary encoder switch, aka "quadrature encoder". It has two outputs that are 90 degrees out of phase. Due to the phase difference you can figure out both direction and number of steps. Same principle is used in a mechanical computer mouse.

Rotary encoder on Wikipedia