SW-420 Normally Closed Vibration Sensor Module
High-Sensitivity Motion and Tilt Detection Sensor for Security Alarms and Microcontrollers
The SW-420 Normally Closed Vibration Sensor Module is an efficient, highly sensitive motion-detection board engineered for alarm systems, anti-tamper devices, and smart impact monitoring. Built around an internal metallic roller switch, the sensor operates in a Normally Closed (NC) default state—meaning current flows continuously through the module when at rest. Upon detecting physical vibration, shock, or sudden movement, the internal contacts temporarily bounce apart, breaking the circuit and driving the digital output pin HIGH to instantly trigger microcontrollers like Arduino, ESP32, or Raspberry Pi.
Equipped with an onboard LM393 comparator circuit, the module features an adjustable precision potentiometer to easily calibrate vibration sensitivity levels according to your project's environment. The board includes clear LED indicators for power and digital trigger status, as well as a 3-pin interface (VCC, GND, DO) that connects seamlessly to standard breadboards and jumper wires. Thanks to its anti-tamper NC design, any deliberate cutting of the sensor wires triggers an immediate system alert, making it an ideal choice for motorcycle security, window glass-break detectors, smart earthquake alarms, and structural vibration monitoring.
Technical Specifications
| Feature | Specification |
| Sensor Type | SW-420 (Normally Closed) |
| Operating Voltage | 3.3V – 5.0V DC |
| Output Type | Digital Switching Output (0 / 1) |
| Onboard IC | LM393 High-Precision Voltage Comparator |
| Idle State Signal | Digital LOW (0) |
| Triggered State Signal | Digital HIGH (1) |
| Sensitivity Adjustment | Integrated Potentiometer |