The HC-020K photoelectric speed measurement module is a compact optical encoder-style sensor designed to convert rotational motion into clean digital pulse signals. It uses a slotted encoder disc (included, 25.6mm diameter) passing through an optical interrupter to generate pulses as the disc rotates. By counting pulses over time (frequency measurement) or measuring time between pulses (period measurement), your controller can calculate RPM, angular velocity, or relative speed. This module is commonly used in DIY robotics, motor speed monitoring, and feedback systems where contactless sensing reduces mechanical wear and improves repeatability.
The HC-020K photoelectric speed measurement module is a compact optical encoder-style sensor designed to convert rotational motion into clean digital pulse signals. It uses a slotted encoder disc (included, 25.6mm diameter) passing through an optical interrupter to generate pulses as the disc rotates. By counting pulses over time (frequency measurement) or measuring time between pulses (period measurement), your controller can calculate RPM, angular velocity, or relative speed. This module is commonly used in DIY robotics, motor speed monitoring, and feedback systems where contactless sensing reduces mechanical wear and improves repeatability.
This module operates on the photo-interruption principle: an IR emitter and receiver face each other across a gap. When the encoder disc’s slots pass through the gap, the light path alternates between blocked and unblocked, producing a pulse train. The onboard circuitry conditions the sensor signal into a logic-level output on the OUT pin. Many HC-020K boards are marketed as “double speed measurement,” typically indicating two pulse outputs per mechanical slot cycle or a higher effective pulse rate; the exact pulse-per-revolution relationship depends on the disc slot count and the specific board revision, so it’s best verified during calibration.
For accurate RPM measurement, connect OUT to a microcontroller interrupt-capable pin and count rising (or falling) edges over a fixed gate time (e.g., 100 ms to 1 s). For higher precision at low speeds, measure the time between edges using a hardware timer. Debouncing is generally not required because the output is optical, but electrical noise from motors can couple into wiring; use short leads, proper grounding, and optional RC filtering or software validation if needed.
HC-020K module, 25.6mm encoder disc, jumper wires set
Honest takes from buyers who built with this part.
Ask anything — the team and other customers will reply.
