Охранная сигнализация состоит из датчиков, which directly control the guard zone, and then transmit the signal to the console. The latter already processes the data with the help of microprocessors and gives the command to actions. It can be a sound siren or automatic dialing to the security service. Elements are grouped by zone and control only their specific area. The motion and glass breakage sensor can be a single device and at the same time monitor sound and temperature changes. It is set to a sharp temperature fluctuation, rather than a gradual one, so false alarms are excluded.
Depending on the events that can trigger an alarm, detectors are distinguished by the following types:
- movement;
- discoveries;
- sensor glass breaking;
- vibration;
- to touch or approach;
- alarm buttons.
All sensors can be combined or combined.Detectors can also be separated by signal transmission. They can be wireless and wired. The first still bear the name of radio channel. In wired power supply is carried out on a two-wire loop, or 4-wire detectors are provided with a power line from the unit. There is also a system where contacts are opened in the microswitch, after which an alarm signal is given.
Kinds
The glass break detector (sensor) is usedon objects to detect damage and unauthorized access. In this case, the system transmits an alarm signal, or emits a sound. Types of such sensors depend on the principle of their action.
They can detect the following changes:
- Violation of the integrity of glass by mechanical action. For this purpose, electric contact detectors are intended.
- Oscillations of the glass surface under mechanical action. These sensors are piezoelectric or shock-contact.
- The vibrations of sound waves at the frequency of the sound of breaking. This is an acoustic glass break sensor.
Electrocontact
Such a detector is attached directly to theglass and can look like a small wire or a piece of metal foil. A current is suitable for this device. The sensor is triggered by a violation of the electrical circuit design if the integrity of the conductive element is damaged.
With the development of more progressive detectors,this type is rarely used. This is due to the fact that such an element on the glass immediately strikes the eye, it can not be sealed, and the costs of production and installation are very high. The scheme of the glass breakage sensor is given later in the article.
Acoustic
Such detectors are triggered when theirThe sensor responds to sound waves whose frequency is similar to the sound of glass breaking. It is laid in the factory. Such devices have a strong sensitivity and the ability to accurately capture the spectrum of certain sounds. The advantage of this type is that it is a wireless glass break sensor.
To date, these are some of the most popularsecurity elements. All due to the fact that they are easily and quickly mounted. You can do this indoors on any vertical surface or ceiling.
Piezoelectric
A glass break detector of this type catches up thosefluctuations that occur when the integrity of the window is lost. The piezoelectric elements inside the device capture the smallest mechanical vibrations coming from the transparent glass and convert them into an electrical signal. Such a sensor, like an electrocontact sensor, is located directly on the surface. This does not allow to use it on large objects or buildings, where non-standard architecture.
Functions
The main function of the glass break detectoris giving them a sound signal when the surface of the protected object is broken. In this case, the device has a number of programs that allow you to avoid triggering false alarms inside the room. Allow it to implement special additions:
- a device for monitoring the unauthorized opening of the sensor casing;
- modes of testing;
- sensitivity adjustment.
Detector Selection
The purchase of the sensor confuses not only its owncharacteristics and functions, but also the manufacturer. Produce similar elements of security alarm in many countries, so the market abounds not only domestic, but also foreign samples. The difference can be seen only with in-depth consideration. For example, some foreign manufacturers may not take into account when designing such windows that were installed in Soviet times.
- a wooden frame may deform with time, which will transmit waves from broken glass not as from a modern plastic double-glazed window;
- The wooden window has a small pane, which also affects the acoustic data;
- typical designs have a certain thickness of glass;
- the installation of glass in the opening was carried out with the help of glazing beads, the cracks were sealed with putty, which eventually lost its plasticity and distorted the sound when broken;
- glass, which has served more than 10 years, has in its structure scratches and various irregularities, which are caused by natural phenomena.
By functions and characteristics of moderndomestic sensors are not inferior to foreign analogues. In any case, during production, it was possible to simplify certain factors, such as room acoustics. The cost and installation of foreign detectors in some cases is much more expensive.
Installation
The installation of a glass break detector of different types has its differences, but important requirements remain. The main one is the right choice of installation site.
- The detector must be in the visibility zone of the protected glass, and its microphone must be directed directly to the object.
- The distance to the object should not be more than 3,6meter. Even if the test by the tester indicates that the system is operating and at a greater distance, there is no guarantee that the device will catch the sound well when the room acoustics change.
- Curtains on the window can interfere with the correct operation of the element. Therefore, it is desirable to install it behind curtains and at close range.
- The distance to the floor should be not less than 1.8 meters.
- Do not install the detector on the same wall as the protected object.
- Operation of the sensor will be ineffective in places with a high noise level.
- Periodically, the element should be checked for operability, creating false noises.
Detector Check
Ensure that the device is locatedcorrect, will help pre-check. Glass break sensors, the principle of operation of which is based on sensitivity to noise of a certain frequency, are checked with a special device - a tester. The operation is considered completed if the device responds to the tester three times in a row. If not, then you should change its location or remove interfering objects (curtains, curtains).
When it is required to protect several windows, the tester should be located at the far end of the glass from the detector. At high or, conversely, insufficient sensitivity of the element, it can be adjusted.
So, we found out what the glass breakage sensors work. Now the choice is yours!
