Rotary Encoder Module
A KY-040 rotary encoder reports rotation steps and direction with two digital signals, plus a press switch.
Part images
What it is
A KY-040 rotary encoder reports rotation steps and direction with two digital signals, plus a press switch.
How students use it
Students use it for menus, volume knobs, scrolling values, games, and precise input controls.
Pins and power
CLK, DT, SW, +/VCC, and GND on common KY-040 boards.
Passive/digital encoder module. Use Pico-safe pull-ups or module output wiring.
CLK and DT are quadrature outputs. Compare which signal changes first to determine direction.
Voltage and safety
Use Pico-safe logic levels on CLK, DT, and SW.
Do not twist past mechanical stops or soldered mounting stress.
Module internals
Main component: Incremental rotary encoder with push switch.
Encoder contacts, push switch, pull-up/support components, PCB, and header.
Datasheet notes
Mechanical encoders bounce, so code should debounce and handle step state carefully.
Common libraries
Use machine.Pin interrupts or polling with debouncing.
Common mistakes
Reading only one signal, missing debounce, counting multiple transitions per click unexpectedly, and swapping CLK/DT.