HW-040 Rotary Encoder Module with Push Button & Knob - 360 Degree

Specifications

• Type: Incremental Encoder (HW-040).

• Cycles per Revolution: 20 pulses.

• Rotation: 360-Degree Continuous (Infinite).

• Integrated Switch: Momentary Push-button (Centre shaft).

• Operating Voltage: 3.0V to 5.5V DC.

• Logic Compatibility: 3.3V and 5V.

• Interface: CLK (Pulse), DT (Direction), SW (Switch), +, GND.

• Included Accessory: High-quality push-fit plastic knob.

Key Applications & Projects

• Menu Navigation: Scrolling through options on OLED or 16x2 LCDs.

• Digital Volume Control: Smooth audio level adjustment for DIY amplifiers.

• Parameter Tuning: Adjusting PWM duty cycles or frequency in lab equipment.

• Robotic Control: Simple manual positioning of stepper motors or servos.

Project Evolution

• Past Projects (Prerequisites): If you've used a standard potentiometer and found it limiting for "infinite" adjustment, you're ready for this.

• Feature Upgrade: This module unlocks State-Machine Logic. Because it outputs Grey Code (two offset square waves), you can program your microcontroller to know not just how much it turned, but in which direction.

• Effort/Requirements: Beginner. Requires a library like Encoder.h or basic interrupt-driven code.

Virtual Technician & Wiring

⚠️ Tech Tip: For the smoothest experience, use Hardware Interrupts on your microcontroller (Pins 2 & 3 on Arduino Uno) to capture every pulse without missing a step.

Package Includes: 1 x  HW-040 Rotary Encoder Module with Push Button & Knob - 360 Degree

Frequently Asked Questions (FAQ)

• Does it have a limit on how many times it can turn? No, it rotates 360 degrees infinitely in both directions.
• Is the knob included? Yes, it comes with a standard black push-fit knob.
• What is the "push button" for? The shaft itself is a switch; you can press it down to select a menu item.
• Does it work with ESP32? Yes, it works perfectly with 3.3V logic.
• Why are the values "jumping" when I turn it? This is usually "switch bounce." Use a library with debouncing or add 0.1uF capacitors to the CLK/DT pins.
• Can I use this as a volume knob? Absolutely, it's the most common part for digital volume control.
• Does it need soldering? The module usually comes with header pins pre-soldered.
• What is Gray Code? It’s the sequence of pulses (CLK and DT) used to determine the rotation direction.
• How many pulses per full turn? 20 pulses per 360-degree revolution.
• Is it better than a potentiometer? For digital interfaces, yes. For analog voltage division, no.
• Can I use it with a Raspberry Pi? Yes, use the GPIO pins with internal pull-ups enabled.
• Is the shaft plastic or metal? Most KY-040 variants feature a durable metal shaft.
• How do I mount it? It can be panel-mounted via the threaded shaft or plugged into a breadboard.
• What is the thread size of the shaft? Typically M7.
• Does the module have pull-up resistors? Yes, the PCB includes 10k pull-up resistors for the CLK and DT pins.
• Can I use it with Micropython? Yes, there are many simple libraries for Rotary Encoders in Micropython.
• What happens if I swap CLK and DT? The encoder will still work, but the "Up" and "Down" directions will be reversed.
• Does the push-button have a pull-up resistor? Often no; use INPUT_PULLUP in your code for the SW pin.
• Can it handle high-speed rotation? It is designed for human input (hand-turning), not for high-speed motor RPM sensing.
• Is the knob removable? Yes, it is a standard D-shaft or knurled-shaft push-fit knob.