SW-1801P Normally Open Vibration Sensor Switch Module – Alarm Trigger for DIY Electronics, Security Devices, and Motion Detection

Description

The SW-1801P Vibration Sensor Module is a compact, low-cost motion detection board designed for alarm systems, anti-theft devices, and vibration-triggered electronics. It uses a normally open spring-switch (the SW-1801P) as the sensing element: at rest, the internal spring is separated from the central electrode, leaving the circuit open. When vibration or shock occurs, the spring oscillates and briefly contacts the electrode, closing the circuit . An onboard LM393 comparator converts this momentary contact into a clean digital output signal with strong driving capability (>15mA), making it suitable for direct connection to microcontrollers or logic circuits .

The module operates from 3.3V to 5V, compatible with Arduino, ESP32, and most hobbyist platforms. An onboard potentiometer allows sensitivity adjustment, though the module is designed for presence detection rather than quantitative vibration measurement. Power and output indicator LEDs provide visual feedback during setup. The compact PCB measures approximately 32×14mm with mounting holes for secure installation .

Important limitation: The module triggers briefly on small vibrations—often too short to directly drive a relay. Suppliers explicitly warn that connecting this module directly to a relay module “does not work well in practice” . For relay control, use a microcontroller to latch the signal or add a monostable circuit. The AO pin is non-functional on this vibration sensor module .

Features

• Normally Open Spring Switch Element: The SW-1801P switch is open at rest and momentarily closes during vibration, providing omni-directional shock detection .

• LM393 Comparator with Clean Digital Output: Provides stable HIGH/LOW switching with >15mA drive capability for direct MCU connection .

• Active-LOW Output Logic: DO outputs HIGH when stationary and LOW when vibration is detected, with the onboard LED illuminating during detection .

• Adjustable Sensitivity: Onboard potentiometer allows threshold tuning to reduce false triggers from ambient vibration.

• Wide Voltage Compatibility (3.3V–5V): Works with both 3.3V and 5V logic systems .

• Compact PCB with Mounting Holes: 32×14mm board with fixed bolt holes for easy installation .

• Low Power Consumption: Approximately 15mA during operation, suitable for battery-powered applications .

• Short Trigger Pulse: Detection pulses are brief; for relay control or sustained alarms, a microcontroller latch or monostable circuit is required .

Technical Specifications