Rotary Encoder Module KY-040 🎛️

The Rotary Encoder Module KY-040 is a reliable incremental (quadrature) rotary encoder with an integrated push-button, ideal for precise user input in Arduino, Raspberry Pi, and other microcontroller-based projects. Designed for accurate control and easy integration, it’s a go-to choice for menu navigation, parameter tuning, and interactive control panels.

Key Features ⚙️

• 360° continuous rotation with tactile feedback for intuitive control
• Incremental encoder outputs two quadrature signals (CLK and DT) for direction and step detection
• Integrated push-button switch (SW) for selection or reset actions
• 5-pin interface: VCC, GND, SW, DT, CLK for straightforward wiring
• Engineered for Arduino, Raspberry Pi, ESP32, STM32, and other electronics modules
• Ideal for user interfaces, robotics, and embedded systems requiring robust rotary input

Technical Specifications 📐

• Operating Voltage: 5 V
• Dimensions: 31 mm × 29 mm × 19 mm
• Resolution: 20 pulses per revolution (PPR)
• Maximum Rotational Speed: 60 RPM
• Operating Temperature: -30 to +85 °C

Pinout & Signals 🔌

• VCC: 5 V supply
• GND: Ground
• CLK (A): Channel A quadrature output
• DT (B): Channel B quadrature output (90° out of phase with CLK)
• SW: Push-button output (momentary)

Tip: Read CLK and DT on GPIO pins (with interrupt or polling) to determine direction and step count. The SW pin provides a digital signal for button presses.

Typical Connections for Microcontrollers 🧰

• Arduino: Connect CLK and DT to digital GPIO (optionally interrupt-capable), SW to a digital input, and VCC/GND to 5 V/GND.
• Raspberry Pi: Connect CLK, DT, and SW to GPIO with proper level considerations. If your system is 3.3 V-only, ensure voltage compatibility (e.g., level shifting or powering the module appropriately).
• Best Practice: Implement software debouncing or filtering; mechanical encoders can produce contact bounce.

Applications 🚀

• Volume control in audio systems
• Control panel dials for appliances and instrumentation
• Robotics parameter tuning and motion menus
• Menu navigation and selection in embedded UIs
• DIY electronics and prototyping with Arduino and Raspberry Pi

Why Choose KY-040? ⭐

• Accurate quadrature output for reliable direction and step detection
• Compact module size for easy integration in enclosures
• Broad compatibility with popular electronics components and modules

Package Contents 📦

• 1 × Rotary Encoder Module KY-040

Notes for Engineers 🧪

• At 20 PPR, you can decode up to 80 counts per revolution with full quadrature decoding (x4), if supported by your firmware.
• Observe the 60 RPM limit to maintain reliable edge detection on slower microcontrollers or when not using interrupts.
• Ensure proper pull-up/pull-down configuration and debouncing in software for stable readings.