In the field of security, home alarm infrared detectors are the “eyes” of the anti-theft alarm system. Their role is very important. Home alarm infrared detectors have been widely used in buildings such as fences and buildings with relatively long distances, and infrared pairs. Compared with the shooting fence, it is more resistant to rain, dust, and interference, and is used in villas and single hospitals in home security alarm systems. Infrared?detectors?are relatively high-tech products. Many infrared detectors are installed in places where valuables are stored. With this kind of home? alarm infrared detectors, everyone will be more at ease.
The selection and installation of the home alarm infrared detector will directly affect whether the entire burglar alarm system can function normally and effectively. In the following, the principle of various types of detectors is used as an entry point to briefly describe how to select various types of detectors and the points that should be paid attention to when installing the detectors.
The working principle and product of common home alarm infrared detector
(一), Passive home alarm infrared detector
The passive home alarm infrared detector does not radiate energy to the space, but instead responds to the infrared radiation emitted by the human body. Any object with a temperature above absolute zero degrees Celsius will continuously radiate infrared rays to the outside world. The surface temperature of the human body is 36 ° C, and most of the radiated energy is concentrated in the wavelength range of 8 ~ 12 μm.
In the detection area, the infrared radiation energy of the human body through the clothes is focused on the pyroelectric sensor by the Fresnel lens of the detector. When the human body (intruder) moves in this detection range, it sequentially enters a certain viewing zone of the Fresnel lens, and then exits the viewing zone, and the pyroelectric sensor “sees” the moving human body for a while, Then, “see” is not available, and the pyroelectric signal that changes when the human body moves triggers the detector to generate an alarm signal. The frequency of the sensor output signal is approximately 0.1 to 10 Hz. This frequency range is determined by the Fresnel lens in the detector, the speed of motion of the human body, and the characteristics of the pyroelectric sensor itself. Passive home alarm infrared detectors can be mounted directly on walls, ceilings or corners depending on the viewing zone detection mode. The principles of placement and installation are as follows:
1. The installation height is usually 2~4 m. At this height, the detector can obtain the maximum detection effective distance.
2. The detector is most sensitive to the human motion of the lateral cut detection field of view, so this feature should be used to achieve the best results when installing.
3, should pay full attention to the detection of the background of infrared radiation, and the background of the choice is not moving.
4. It is best not to have air conditioning or heat source in the warning zone. If the heat source cannot be avoided, keep the distance between the heat source and the heat source at least 1.5m, and the detector should not be aligned with the air outlet of the bulb, stove, refrigerator radiator or air conditioner.
5, the detector should not be aligned with a strong light source, should avoid the place where the sun or the sun is reflected, should also avoid the window.
6. Do not interfere with the obstructions and electric fan blades in the detector area, and do not install them near strong electromagnetic radiation sources (such as radio transmitters and motors).
7. Passive home alarm infrared detectors should not be installed on objects that are easy to vibrate. Otherwise, the vibration of the object will cause the detector to vibrate, which is equivalent to the change of background radiation, which will cause false alarms.
8, pay attention to the detector’s viewing angle range to prevent “dead angle”.
Once the intruder enters the detection area, the infrared radiation of the human body is focused by the partial mirror, and is received by the pyroelectric element, but the two pieces of pyroelectric elements receive different heat, and the pyroelectric power is different, which cannot be cancelled, and is processed by signal. And the alarm.
(二), Active home alarm infrared detector (infrared sensor , infrared fence)
The active home alarm infrared detector consists of a transmitter and a receiver. The transmitter emits an infrared beam to a receiver that is installed in the opposite direction and is several meters or tens of meters or even hundreds of meters away. When the infrared beam is blocked by the object, the receiver sends an alarm signal, so it is called for infrared radiation detectors or infrared fences. Infrared beams have two beams, three beams, four beams, etc. The infrared fence is generally above four beams, and even up to a dozen beams. Active home alarm infrared detectors should be installed on fixed objects, especially when the transmitter and receiver are far away. Whether the transmitter is a receiver or not, slight sloshing will cause false alarms, and try to avoid leaves and swaying the body to the infrared. Beam interference. When using multiple pairs of infrared radiation detectors or infrared fences to form a light wall or an optical network, it is necessary to avoid eliminating the cross-injection of the infrared light beam by reasonably selecting the installation position of the transmitter and the receiver so that no cross-injection occurs, or Infrared radiation detectors with different frequencies are selected to adjust the detectors to work in different frequency segments.
Receiver parameters: ≤20m
Scope: When bad weather such as heavy rain or fog, the distance will be reduced by 30%.
Infrared emission frequency: 1.92Khz
Input power: DC / AC 12-24
Input current: RX 15mA-TX 30 mA
Angle of incidence: <±10°
Operating environment: -20 ° C ~ 70 ° C
Maximum load: 1A max? 30V
Active infrared radiation size: 100×35×40mm
Note: Due to the large transmission power of this product, when the transmitter and receiver are too close, there will be no reaction. In this case, pull them apart for at least 1 meter and try again. When the installation distance is very close, an insensitivity phenomenon is found, and the concentrating lens in the transmitting and receiving can be removed to improve the sensitivity.
Installed the home alarm infrared detector, no longer afraid of the thief’s intrusion, once triggered, immediately alarm, so that the thief has nowhere to hide! Its security and application is higher. Yaoertai Technology has been focusing on the development and production of various security products such as infrared radiation for more than ten years. The quality is excellent, the system is excellent, and it is trustworthy. Please feel free to inquire and cooperate!
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