KY-040 Rotary Encoder Module 5V with Push Button for Arduino and Raspberry Pi

Incremental rotary encoder, 5 V operating voltage, 20 pulses per revolution. This encoder converts rotational movement into clean digital pulses, counts in both rotation directions, and can be reset to zero using the built-in push button. Key benefits - Accurate position feedback: 20 pulses per revolution provide reliable incremental measurement for angle and position control. - Direction detection and bidirectional counting: counts pulses when rotated clockwise or counterclockwise, enabling precise tracking of movement and direction. - Resettable to zero: integrated push button returns the count to the initial state, simplifying calibration and user control. - Stable, noise-resistant output: photoelectric scanning and a differential two-signal output with 180 degree phase shift improve signal quality and reduce interference. - Ready for digital systems: designed for 5 V logic environments and compatible with standard microcontroller counters and decoding circuits. What it does and how it works - Operation principle: the encoder uses an optical scanning method that exposes alternating light and dark windows on a rotating disk to an infrared light source. A receiver with a diffraction grating captures the light pattern and converts rotation changes into electrical signals. - Signal conditioning: low-level sensor signals are amplified and shaped into clean square pulses by the encoder electronics. Two channels with a 180 degree phase relationship are provided to allow reliable pulse counting and direction determination. - Reset functionality: a mechanical push button on the encoder resets the pulse count back to zero when needed. Important specifications - Operating voltage: 5 V. - Pulses per revolution: 20. - Counting behavior: bidirectional pulse counting with reset-to-zero via encoder push button. - Output characteristic: photoelectrically generated incremental pulses with differential two-signal output for improved stability. Performance and compatibility - Designed to interface with typical 5 V digital inputs and microcontroller counters. The encoder requires a decoding circuit or firmware routine to interpret pulse trains and determine absolute or relative position. - Delivers consistent, interference-resistant pulses suitable for control loops, user interfaces, and position tracking tasks. Practical applications - Motor control and motion feedback: use the encoder for closed-loop speed or position control in small motors and actuators where incremental position data is needed. - Human machine interfaces: integrate as a rotary input knob with push-to-reset for menu selection, parameter adjustment, or manual calibration in control panels and instruments. - Robotics and automation: provide wheel or joint position feedback for mobile robots, conveyor systems, and automated mechanisms that require directional counting and reset capability. Why choose this encoder - Simple integration into 5 V systems with clear, resettable incremental feedback. - Optical sensing and differential outputs reduce signal errors and improve reliability in noisy environments. - Built-in push button simplifies zeroing and calibration without additional hardware. Notes for integration - Ensure an appropriate decoding circuit or microcontroller routine is used to read the two phase-shifted signals and to implement counting and direction logic. - The encoder provides incremental pulses and requires external logic or software to maintain absolute position if needed.