About the anti-pet function of the passive infrared detector
The development of passive infrared detectors today is relatively mature in technology. The prevention of small pets is an important function of passive infrared detectors. Each manufacturer's handling of small pets' interference is different, but nothing more than There are two methods: one is the physical method, that is, the probability of false alarms caused by small pets is reduced by changing the division method of the Fresnel lens. This method is superficial and the effect is limited. The second method is to process and analyze the detection signal, which is mainly to collect data from the detected signal, and then analyze the signal period, amplitude, and polarity. These factors specifically reflect the speed of the moving object, the amount of pyroelectric infrared energy, and the displacement per unit time. The microprocessor in the detector analyzes and compares the collected data to determine whether the moving object may be a human or a small animal.
From this point of view, we should pay attention to the function of the passive infrared detectors against pets is relative. This relativity includes two aspects. One is that pet prevention is relative. Compared with a detector without a pet prevention function, the false alarm rate is greatly reduced. It has a certain limit on the number and size of small pets. The second aspect is that the installation position must have certain requirements, and the pet-proof function can not be achieved by random installation. When installing, you must carefully understand the specific requirements in the manual of the detector.