Aiming at the problem of illegal intrusion monitoring such as cable trench, Swift Wireless has designed a set of human infrared sensor (adjustable sensing distance) monitoring device to realize multi-dimensional monitoring of complex environment of cable well. On the premise of mature NB-IoT IOT communication means, the diffuse reflection principle of human infrared sensor is used to determine whether it is the monitoring of illegal invasion. In line with the application design direction of not delaying judgment and good judgment, it provides reliable data judgment basis for background operation and maintenance personnel and makes corresponding countermeasures in time. Product features: infrared short-distance diffuse reflection; Bring your own battery power supply; Low power consumption design; It can work normally under dark conditions at night. No alarm will be generated for special circumstances such as fast moving objects (e. g. falling rocks), dry dust coverage, clear water attachment, etc. To avoid misjudgment. Applicable environment: cable trench, pipeline well and non professionals should not enter the control environment.