Door Sensor (Magnetic Contact Switch)

This magnetic contact switch is a compact way to detect when a door, window, or drawer opens or closes. Inside the ABS plastic shell sits a sealed reed switch: normally closed, so the two wires are connected until a magnet comes within about 13 mm (0.5 in) and pulls the switch open. When the door is shut, contact opens; when opened, contact closes again—ideal for simple security systems, cabinet or fridge monitoring, or interactive projects that trigger when a panel is opened.

Key Specs

• Type: Normally closed (NC) reed switch
• Mounting: ABS plastic body with tabs for screws or adhesive tape
• Operating distance: Up to about 13 mm (0.5 in) when magnet is aligned
• Contact rating: Low‑voltage, low‑current digital sensing (typically used with 3.3–5 V and pull‑up resistor)
• Wiring: Two wires (no polarity); just connect as a switch in series with a 10 kΩ pull‑up resistor to your microcontroller input
• Environment: Simple indoor use; avoid slamming or bending to prolong life

Note: Actual operating distance and contact life may vary depending on magnet strength, alignment, and mechanical wear. Always test the switch in place and consider using it with a pull‑up resistor and software debouncing for cleaner digital signaling.

Disclaimer: The images shown are for illustration purposes only and may not be an exact match.