Gikfun MC-38 Wired Door Sensor Magnetic Switch for Arduino EK1656 MC-38 Wired Door Window Sensor Magnetic Switch Home Alarm System Detector Note: No external power supply, connect to wired or wireless alarm control panel GND and N.C ports directly! Please note that this item not fit to iron door, It will decline magnetic of the sensor MC-38 Wired Door Window Sensor Magnetic Switch Home Alarm System Detector It can be connected to ESP8266 to control the garage door. Note: No external power supply, connect to wired or wireless alarm control panel GND and N.C ports directly! Please note that this item not fit to iron door, It will decline magnetic of the sensor