Rotary Encoder Brick Sensor Module (KY‑040)

This small module is an incremental rotary encoder designed as an easy‑to‑use input device for microcontrollers such as Arduino, ESP32, or Raspberry Pi. Instead of a limited‑angle potentiometer, it spins freely in 360° and outputs digital pulses you can count to track how much and in which direction the knob has turned.

How it works

• The encoder converts angular displacement into a series of digital pulses; typical “one‑round” pulse count is about 20 pulses per revolution (PPR).
• It outputs two square‑wave signals (A and B, or CLK and DT) with a 90° phase difference; comparing the timing of these pulses lets your code detect rotation direction and steps.
• The built‑in push‑button on the shaft can reset the count or act as a separate “select/confirm” input, starting counting from 0 when pressed.

Electrical specs and connections

• Operating voltage: 3.3–5 V DC, typically powered from the board’s 5 V rail.
• Pins (standard KY‑040 module):
  • GND – ground
  • (VCC) – 3.3–5 V power
  • CLK (A) – quadrature output channel A
  • DT (B) – quadrature output channel B
  • SW – push‑button output (normally open, pulled to GND when pressed)

Typical uses

• Volume or menu control knobs on DIY audio or display interfaces.
• User input for motor‑control, CNC‑style jogs, or parameter tuning on embedded projects.

Note: Exact dimensions and pulse count may vary slightly by vendor, but “one round = 20 pulses” is the common spec.
Disclaimer: The images shown are for illustration purposes only and may not be an exact match.