ProTechTrader MC-31B Magnetic Reed Switch Wired Door Sensor Alarm NC (Model: PTT-MC-31B)

Enhance your security and automation projects with the MC-31B Magnetic Reed Switch Wired Door Sensor (PTT-MC-31B), a professional-grade magnetic sensor designed for detecting when doors, windows, or gates are opened or closed. This versatile sensor features both Normally Closed (NC) and Normally Open (NO) contacts, making it compatible with virtually any alarm system, security setup, or automation project.

The MC-31B operates using a simple but reliable magnetic reed switch mechanism: when the magnetic piece is near the sensor, the internal reed contacts either connect or disconnect (depending on whether you use the NC or NO terminal). Move the magnet away, and the state reverses. This simple operation makes it perfect for detecting door/window status, triggering alarms, automating lights, or monitoring access points in security systems.

Technical Specifications & Features:

• Dual contact configuration: NC (Normally Closed) and NO (Normally Open)
• Pre-wired with approximately 12 inches of cable
• Surface mount design with screw holes for easy installation
• Durable ABS plastic housing
• Includes magnetic actuator piece
• Operating gap: Activates when magnet is within 20mm
• Compatible with 12V-24V security systems
• Low power consumption (no active power required)
• Weather-resistant construction suitable for outdoor use

Ideal for DIY security systems, home automation projects, Arduino/Raspberry Pi applications, and professional security installations. Common uses include door/window security sensors, garage door monitors, mailbox notifications, cabinet alarms, and smart home automation triggers. The dual NC/NO configuration provides maximum flexibility for integration with various control systems and monitoring equipment.