Burglar alarm is, of course, the most reliable means of protecting your home from unauthorized entry. The inscription on the fence "Caution, angry dog!" in our time, you won’t scare even small children, not like the “pros” who have looked after an apartment (or a private house) in advance and are preparing to pay a visit in the absence of the owners. The eyes of any security (fire and security) alarm are detectors.
There are many types of detectors. Some respond to the opening of doors and windows, others to breaking glass, and others to increased vibration. There are also those who "see" any changes in the thermal background in the protected area in infrared light. Some detectors, such as Astra-621, combine several methods of detecting intruders at once.
Benefits
This device belongs to the category of combined. Astra-621 is a security detector that combines two detection channels at once.
The first has a volume optoelectronic infrared sensor. Thanks to this function, Astra-621 is able to "detect" any movement of a body that radiates heat in a protected area. Some simple security systems generally manage only with sensors of this type.
The second is a glass break sensor. Citizens of the older generation probably remember the security alarm sensors glued with epoxy compounds to the glass from the inside of the premises. The Astra-621 detector has nothing in common with such a primitive. Modern glass break sensors are installed indoors and "protect" all the windows in the room at once.
Working principle
How do the Astra-621 systems operate?
Volumetric optoelectronic infrared sensor "illuminates" the room with built-in IR LEDs and monitors the thermal background. Any warm-blooded living being, including humans, "glows" in the infrared background.
When a heat-radiating object penetrates the protected object, a sharp drop in the IR background occurs, which is captured by the sensor. But if some cunning thief comes up with the idea to get into the house, dressed in a suit that reflects infrared rays, nothing will come of it. Even pretending to be cold-blooded, moving around the room, he will block the IR rays, which again will cause a change in the thermal background.
The working principle of the glass break sensor is even simpler. In short, Astra-621 has a built-in microphone that responds tothe sound of a broken glass window. Any event occurring in the earth's atmosphere generates sound vibrations with a certain set of frequencies, amplitudes and other characteristics. We, for example, accurately identify the voices of people we know, distinguish a mobile phone signal from a doorbell.
The detector also filters the vibrations entering the microphone, so that the alarm will only be raised by the sound of breaking glass, and certainly not by the sound of a thunderstorm or a truck passing by the house.
Specifications
- reacts to the sound of broken glass up to 6 m away;
- IR background change detection angle is 90°;
- installed above the floor at a height (optimal) 2.4 ± 0.1 m;
- working voltage is 8-15V;
- current consumed in standby mode – 0.015 A;
- maximum allowable current - 0.1 A;
- maximum EMF on the relay contacts - 100 V;
- dimensions - 11x6x4, 3 cm;
- weight – 100 gr.;
- can be operated in the temperature range from -20 to +50 °С and at air humidity up to 94%.
