The security alarm system consists of sensors that directly monitor the security zone, and then transmit the signal to the control panel. The latter is already processing data using microprocessors and gives the command actions. It can be a sound siren or automatic dialing into a security service. Elements are combined in zones and control only their specific area. The motion and glass break sensor can be one device and at the same time monitor sound and temperature changes. It is configured for a sharp temperature fluctuation, and not for a gradual one, therefore false alarms are excluded.
Depending on the events that may cause an alarm, the detectors are distinguished by the following types:
- movement
- discoveries;
- glass break sensor;
- Vibration
- to touch or approach;
- panic buttons.
All sensors can be combined or combined. Detectors can be divided into signal transmission. They are wireless and wired. The first are still called radio channels. In wired, power is supplied via a two-wire loop, or 4-wire detectors are provided with a power line from the unit. There is also a system in which contacts are opened in the microswitch, after which an alarm is given.
Kinds
A glass break detector (sensor) is used at objects to detect damage and unauthorized access. In this case, the system transmits an alarm or makes a sound. The types of such sensors depend on the principle of their action.
They may detect the following changes:
- Violation of the integrity of glass by mechanical action. For this purpose contact detectors are designed.
- Oscillations of the glass surface during mechanical action. These are piezoelectric or shock contact sensors .
- Oscillations of sound waves at the frequency of the sound of breaking. This is an acoustic glass break sensor.
Electrical contact
Such a detector is mounted directly on the glass and can take the form of a small wire or part of a metal foil. Current is suitable for this device. The operation of the sensor occurs due to a violation of the design of the electrical circuit if the integrity of the conductive element is damaged.
With the development of more advanced detectors, this type is rarely used. This is due to the fact that such an element on the glass immediately catches your eye, it is impossible to decorate it, and the cost of production and installation is very high. The diagram of the glass break sensor is given later in the article.
Acoustic
Such detectors are triggered when their sensitive element responds to sound waves whose frequency is similar to the sound of glass breaking. It is laid at the factory. Such devices have 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 detector.
Today, these are one of the most popular security elements. All due to the fact that they are easily and quickly mounted. This can be done indoors on any vertical surface or ceiling.
Piezoelectric
A glass break sensor of this type picks up those vibrations that occur when the window integrity is lost. The piezoelectric elements inside the device pick up the tiniest mechanical vibrations coming from transparent glass and convert them into an electrical signal. Such a sensor, like an electric contact, is located directly on the surface. This does not allow its use in large facilities or buildings where non-standard architecture.
Functions
The main function of the glass breaking sensor is to give it an audio signal when the surface of the protected object is violated. In this case, the device has a number of programs that allow you to prevent triggering of false interference indoors. Allow this to carry out special additions:
- tracking device for illegal opening of the sensor shell;
- test modes;
- sensitivity setting.
Detector Selection
Buying a sensor is confused not only by its characteristics and functions, but also by the manufacturer. Similar alarm elements are produced in many countries, therefore, the market is replete with not only domestic, but also foreign models. The difference can only be seen with deep examination. For example, some foreign manufacturers may not consider such window designs that were installed in Soviet times when developing.
They have a number of characteristics:
- a wooden frame can become deformed over time, which will transmit waves from broken glass differently from a modern plastic double-glazed window;
- the wooden window has a small window, which also affects the acoustic data;
- typical designs have a certain thickness of glass;
- installation of glass in the opening was carried out using glazing beads, the cracks were closed with putty, which eventually loses plasticity and distorts the sound when broken;
- glass, which has served for more than 10 years, has in its structure scratches and various irregularities that are caused by natural phenomena.
By functions and characteristics, modern domestic sensors are in no way inferior to foreign counterparts. In any case, during production, some factors could be simplified, such as room acoustics. The cost and installation of foreign detectors in some cases is much more expensive.
Mounting
Installing a glass break sensor of different types has its own differences, but important requirements remain. The main one is the right choice of installation location.
- The detector should be in the visible area of the protected glass, and its microphone should be aimed directly at the object.
- The distance to the object should be no more than 3.6 meters. Even if the test with a tester shows that the system works at a greater distance, there is no guarantee that the device will well catch the sound when changing the acoustics of the room.
- Curtains on the window can interfere with the correct operation of the element. Therefore, it is advisable to install it behind the curtains and at close range.
- The distance to the floor must be at least 1.8 meters.
- The detector should not be mounted on the same wall as the guarded object.
- The operation of the sensor will be ineffective in places with high noise levels.
- Periodically, you should check the element for performance, creating false noise.
Detector Test
Verifying that the device is positioned correctly will help with a preliminary check. Glass break sensors, the principle of which is based on noise sensitivity 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, you should change its location or remove interfering objects (curtains, curtains).
When it is required to protect several windows, the tester must be located at the end of the glass farthest from the detector. With a high or, conversely, insufficient sensitivity of the element, it can be adjusted.
So, we found out what the principles of breaking glass have. Now the choice is yours!