KY-031 Knock Sensor Module

The KY-031 Knock Sensor Module is a vibration-sensitive input component designed for use with Arduino, Raspberry Pi, ESP32, and other popular microcontroller platforms. At its core, the module uses a spring-based mechanical knock sensor that detects physical taps, vibrations, and impacts — outputting a digital signal whenever movement or shock is detected.

This makes the KY-031 ideal for a wide range of creative and practical applications including anti-theft alerts, vibration-triggered alarms, smart packaging sensors, and interactive art installations. Its simple three-pin interface (Signal, VCC, GND) allows direct connection to sensor shields and breadboards with no additional components required.

The onboard resistor ensures clean, stable signal output without the need for external pull-up circuitry, keeping your wiring tidy and your build straightforward. Compact and low-power, the KY-031 is a reliable choice for any project that needs to sense physical disturbance or impact.

Specification:

• Operating Voltage : 3.3V – 5V DC
• Output Type : Digital (HIGH / LOW)
• Sensor Type : Spring-Based Mechanical Knock Sensor
• Pin Count : 3 (Signal, VCC, GND)
• PCB Dimensions : 15mm x 36mm
• Onboard Resistor : Yes
• Compatible With : Arduino, Raspberry Pi, ESP32/ESP8266
• Output Signal (Idle) : HIGH
• Output Signal (Knock Detected) : LOW
• Sensitivity : Fixed (mechanical spring)