The Contact Sensor is an intelligent home device that uses wireless connection and sensor technology to detect the open/close status of doors and windows. It usually consists of two parts: a magnet and a sensor installed on the door/window frame. When the door/window is closed, the magnet will approach the sensor, creating a closed circuit, allowing the Contact Sensor to determine whether the door/window is closed. If the door/window is opened, the circuit between the magnet and sensor will be disconnected, and the Contact Sensor will detect the status change and send notification to the user. The Contact Sensor can be paired with a smart home system or a smartphone application, allowing users to monitor the status of doors and windows in real-time, as well as ensuring home security at all times.