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Rotary Encoder (KY-040)

Control

Endlessly turning knob that reports a step and its direction at every click; pressing it down also works as a button. Handier than a potentiometer for menu navigation, volume or temperature setting, and counters. The direction comes from which of the two signals on CLK and DT changes first; to avoid missing steps, use interrupt pins (2 and 3 on an Uno) or the Encoder library. Turn on INPUT_PULLUP for the SW pin.

Specifications

Type

Incremental (quadrature) encoder + push switch

Steps

20 clicks (detents) per turn

Rotation

Endless (360°)

Operating voltage

3.3 - 5V

Pins

CLK, DT, SW, + (VCC), GND

Pull-ups

10 kΩ on CLK and DT (use INPUT_PULLUP for SW)

Library

Encoder (Paul Stoffregen) or interrupts

Shop prices

• Modül ElektronikIn stock35.79 ₺
• RobocomboIn stock40.50 ₺
• Robo90In stock44.64 ₺
• HobiDevreIn stock46.08 ₺
• Direnc.netIn stock69.74 ₺
• Robolink MarketIn stock72.00 ₺
• RobotzadeIn stock84.00 ₺
• F1 DepoOut of stock39.00 ₺

Prices read from the shops' pages on 22 October 2026. Prices and stock may have changed since; check at the shop before you buy.

Projects with this part

• Kitchen TimerBeginner30 minA kitchen timer for tea, eggs or pasta: you set the time by turning the rotary encoder, and the 4-digit display shows it as minutes:seconds. Press the knob and the countdown starts, with the colon in the middle blinking once a second; press again to pause, once more to carry on where it stopped, and hold it down to go back to the time you set. When the time is up the buzzer beeps three times a second and the display blinks; a press silences it and the same time is ready to run again. It teaches reading a rotary encoder's direction with an interrupt, telling a short press from a long one on a single button, counting down with millis(), and driving a TM1637 display with two wires. Install "TM1637" (Avishay Orpaz) from the Library Manager.Open project