The NB-IoT parking sensor (Narrowband IoT parking sensor) is a wireless parking space status monitoring device based on cellular mobile communication networks. Installed in each parking space (typically buried or mounted close to the ground), it accurately detects whether the space is occupied or vacant. Data is transmitted directly to a cloud management platform via the NB-IoT network, enabling large-scale, wide-coverage, and city-wide smart parking management. Its core operating principle is: perception → transmission → cloud processing. Perception: Utilizing geomagnetic induction technology, it detects the interference of parked vehicles (metallic objects) with the Earth's magnetic field. Transmission: The built-in NB-IoT communication module encodes status change information. Cloud processing: Data is transmitted directly to a cloud server via the operator's NB-IoT network. Platform software processes and analyzes the data, ultimately generating vacant parking space information.