Bourns PEC11R Rotary Encoder Counter

Turn a clicky 24-detent knob and watch a counter increment or decrement live — the foundation of every menu wheel and volume knob.

Difficulty: Breadboard. Estimated build time: about 30 minutes. Estimated parts cost: about US$3.50. 5-part bill of materials with live supplier pricing. An incremental rotary encoder that converts the motion of your knob into a stream of digital pulses, decoded by the Arduino into a signed counter.