The security alarm system is, of course, the most reliable means of protecting the home from unauthorized entry. The inscription on the fence "Caution, angry dog!" Nowadays, you will not scare even small children, not like “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 opening doors and windows, others respond to breaking glass, and others respond to increased vibration. There are also those who “see” in infrared light any changes in the thermal background in the protected room. Some detectors, such as Astra-621, combine several techniques for 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 volumetric optoelectronic infrared sensor. Thanks to this function, “Astra-621” is able to “detect” in the protected area any movement of the body that emits heat. Some simple security systems generally cost only sensors of this type.
The second is a glass break sensor. Citizens of the older generation will probably remember the burglar alarm sensors glued with epoxy on glass from inside the premises. The Astra-621 detector has nothing in common with such a primitive. Modern glass break sensors are installed indoors and “guard” at once all the windows available in the room.
Principle of operation
How do the systems armed with the Astra-621 work?
The volumetric optoelectronic infrared sensor “illuminates” the room with built-in infrared LEDs and monitors the thermal background. Any warm-blooded living creature, including humans, “glows” in the infrared background.
When an object radiating heat penetrates a protected object, a sharp drop in the infrared background occurs, which is detected by the sensor. But if some cunning thief comes up with the idea of entering the house, dressed in a suit that reflects infrared rays, nothing will come of it. Even pretending to be cold-blooded, he, moving around the room, will block the infrared rays, which again causes a change in the thermal background.
The principle of operation of the glass break sensor is even simpler. In short, Astra-621 has a built-in microphone that responds to the 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 determine the voices of people we know, distinguish the signal of a mobile phone from a doorbell.
The detector filters the vibrations coming to the microphone in the same way, so that the alarm will rise only from the sound of broken glass, and not from the sound of a thunderstorm or a truck passing by.
Specifications
- reacts to the sound of broken glass removed up to 6 m;
- the angle of detection of changes in the infrared background is 90 °;
- installed above the floor at a height of (optimally) 2.4 ± 0.1 m;
- operating voltage is 8-15 V;
- current consumed in standby mode - 0.015 A;
- the maximum allowable current is 0.1 A;
- maximum EMF on relay contacts - 100 V;
- dimensions - 11x6x4.3 cm;
- weight - 100 gr.;
- It can be operated in the temperature range from -20 to +50 ° and with air humidity up to 94%.