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🎛️ KY-040 Rotary Encoder Module with Push-Button - Choose With or Without Knob Cap

Description: The KY-040 pairs a 360° incremental rotary encoder with a built-in push switch, so one component gives you both a turnable dial and a click action — ideal for menu navigation, volume controls or any project that needs a physical knob. Choose the Without cap option for the bare 6mm D-shaft module (fit your own knob), or the With cap option to receive a D-shaft knob cap with each module.

✅ 360° incremental rotary encoder plus an integrated push-button switch on the same shaft — turn and click from one component
✅ 20 detents per revolution, giving smooth, evenly-spaced steps for menu or value scrolling
✅ Two options — check the Knob Cap choice before you buy: Without cap is the module only, with a bare 6mm D-shaft (no knob supplied); With cap includes a knob cap for the D-shaft with every module
✅ UK stock, dispatched daily from our Callander workshop in Scotland
✅ Works with Arduino (Uno, Nano, Mega), ESP32, ESP8266, Raspberry Pi, Raspberry Pi Pico, STM32

⚡ General Component Specifications

Type: Incremental rotary encoder with push-button
Operating Voltage: 3.3V - 5V DC
Detents per Revolution: 20
Switch Type: Momentary push (shaft press)
Board Dimensions: approx. 32 x 18mm
Compatibility: Arduino (Uno, Nano, Mega), ESP32, ESP8266, Raspberry Pi, Raspberry Pi Pico, STM32

📌 Pinout Guide

CLK: Encoder output A — pulses as the shaft turns, read alongside DT to determine direction.
DT: Encoder output B — the second quadrature signal, compared against CLK for direction.
SW: Push-button output — pulls low when the shaft is pressed (needs a pull-up if your board doesn't provide one).
+ (VCC): Power in, 3.3V or 5V.
GND: Ground.

📦 What's Included

Select your pack size from the drop-down above:

1x Pack — one encoder module (with or without knob cap, as selected)
5x Pack — five encoder modules (with or without knob caps, as selected)

Every order includes:

1 x KY-040 rotary encoder module (per unit in the pack)
1 x knob cap per module — With cap option only; the Without cap option ships with no knob

🔧 Quality & Handling Best Practice

Debounce both the rotation and the switch in software. Mechanical contacts bounce on every detent and every press — a few milliseconds of debounce in your code (or a small RC filter) stops double-counted steps and phantom clicks.
Read CLK and DT together, not CLK alone. The direction of rotation is only knowable by comparing which of the two changes first — most encoder libraries handle this for you, but a from-scratch implementation needs both pins.
Don't force the shaft past its detents. It rotates freely with no end-stop — forcing it sideways can crack the internal contacts.
Handle by the edges of the PCB and store in the supplied ESD bag when not in use.

🔄 Returns & Support

This listing has a 30-day return window. If your item arrives faulty or dead-on-arrival, just message us — we typically reply within 24 hours and will sort a replacement or a full refund, no fuss.

Stuck on wiring or getting it talking? Message us before leaving feedback — we use these parts ourselves and are happy to help.

💷 Save More When You Buy Multiples

Buy 2 — save 5%
Buy 3 — save 10%
Buy 4 or more — save 15%

Discounts are applied automatically at checkout — just add the quantity you need to your basket.

🚚 Shipping & Delivery Information

Free UK delivery on every order
Fast daily dispatch from our workshop in Callander, Scotland
Sent in an anti-static ESD bag inside defensive packaging so the pins and PCB arrive undamaged