Passive infrared detection warning device

Abstract

The invention relates to a passive infrared detection warning device which comprises an optical system, a pyroelectric infrared sensor, a signal processing circuit and a warning circuit. The signal processing circuit comprises a band-pass filter and a signal amplifier. The output end of the pyroelectric infrared sensor is connected with the input end of the band-pass filter and the input end of the band-pass filter is connected with the input end of the signal amplifier. The signal amplifier is connected with the warning circuit. A Fresnel lens is adopted in the optical system and a relay for controlling operation of the warning circuit is further connected between the signal amplifier and the warning circuit. A double-detection-element pyroelectric infrared sensor is adopted in the pyroelectric infrared sensor. An infrared radiation high-sensitivity zone and a blind zone which are alternated can be generated so as to adapt to the feature that pyroelectricity detection elements require a signal to change continuously. Thus, the aim of accurately detecting an intruding person is achieved and false reporting or missed reporting is avoided. The passive infrared detection warning device can warn in time and prevent detaching and damaging and safety coefficients of the passive infrared detection warning device are comprehensively improved.

Description

[0001] technical field [0002] The invention relates to the technical field of passive pyroelectric infrared detection, in particular to a passive infrared detection alarm. Background technique [0003] At present, all kinds of anti-theft and security alarms used in China are basically based on technologies such as ultrasonic waves, active infrared emission / reception, and microwaves. However, the detection of the existing alarm is active detection, the detection effect is poor, and it is easy for people to see the installation position of the detector. Potential harm to people's property and personal life. [0004] Nowadays, in foreign countries such as the United States, although there is a pyroelectric infrared sensor, both pyroelectric infrared sensors and thermocouples are pyroelectric infrared sensors based on the principle of pyroelectric effect. The difference is that the pyroelectric coefficient of the pyroelectric infrared sensor is much higher than that of the t...

AI Technical Summary

Problems solved by technology

However, most of the anti-theft alarm devices used by the existing pyroelectric infrared sensors are also actively detected, and the installation position of the detector is easy to be seen by people, causing illegal personnel to disassemble it by detecting the installation position, which also leads to alarm failure and affects the safety of the alarm. Use, causing the alarm to lose the alarm function, bringing potential harm to people's property and people; and the detection range is small, which easily leads to detection blind spots, and is easily interfered by various factors such as animal body temperature radiation, sunlight exposure, and thermal air temperature radiation. And cause false alarms or false negatives; therefore, the safety factor and accuracy rate are not high

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