The wireless intelligent manhole cover detector IDM-400 is installed beneath the manhole cover. It features a built-in IoT operating system and utilizes principles such as light sensing and acceleration detection. When the manhole cover is illegally opened, the system detects the sensor's motion signal. After filtering and threshold analysis, it confirms that it is a genuine abnormal movement of the manhole cover. The system then transmits the message via the NB-IoT network to the intelligent manhole cover system center and mobile app, promptly notifying relevant personnel to take action, thereby minimizing harm and losses. The NB-IoT wireless intelligent manhole cover detector is characterized by high reliability, ultra-long standby time, wireless transmission, and city-wide coverage. The device generates and stores logs (such as manhole cover status monitoring in NB mode and emergency mode, device coding, etc.), enabling real-time responses to changes in the manhole cover status. The NB-IoT wireless intelligent manhole cover detector includes alerts for manhole cover opening and low battery power. It also features configurable scheduled reporting functions, including manhole cover status, battery level, and signal strength.

Schematic Diagram of Working Principle: