The burglar alarm consists of sensors that directly control the security zone, and then transmit the signal to the remote control. The latter is already processing the data with the help of microprocessors and instructs the actions. It can be a sound siren or an automatic call to the security service. Elements are combined into zones and control only their specific area. The motion and glass break sensor can be one device and at the same time track sound and temperature changes. It is set to fluctuate in temperature rather than gradually, so false alarms are excluded.
Depending on the events that can trigger an alarm, detectors are distinguished by the following types:
- movement;
- discovery;
- glassbreak sensor;
- vibrations;
- for touch or proximity;
- panic buttons.
All sensors can be combined or matched. Detectors can also be divided by signal transmission. They are wireless and wired. The first ones are also called radio channel. In wired, power supply is carried out via a two-wire loop, or 4-wire detectors are endowed with a power line from the unit. There is also a system in which the contacts in the microswitch open, after which an alarm is given.
Views
The glass break detector (sensor) is used on objects to detect damage and unauthorized access. In this case, the system transmits an alarm signal, or emits a sound. The types of such sensors depend on the principle of their operation.
They can detect the following changes:
- Violation of glass integrity by mechanical action. Electrocontact detectors are designed for this.
- Vibrations of the glass surface under mechanical action. These are piezoelectric or shock-contact sensors.
- Oscillations of sound waves at the frequency of the breaking sound. This is an acoustic glass break detector.
Electrocontact
Such a detector is attached directly to the glass and can be in the form of a small wire or a piece of metal foil. This device is energized. The sensor is triggered 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 glass immediately catches the eye, it cannot be decorated, and the production and installation costs are very high. Schemeglass break sensor is given later in the article.
Acoustic
Such detectors are triggered when their sensitive element reacts to sound waves, the frequency of which is similar to the sound of breaking glass. It is set 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 easy and quick to install. This can be done indoors on any vertical surface or ceiling.
Piezoelectric
This type of glass-break sensor detects vibrations that occur when the window is broken. The piezoelectric elements located 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 one, is located directly on the surface. This does not allow it to be used on large facilities or buildings with non-standard architecture.
Functions
The main function of the glass break sensor is to give a sound signal when the surface of the protected object is violated. At the same time, the device has a number of programs that allow you to prevent triggering on false interference indoors. Special additions allow this:
- tracking device for illegalopening the sensor shell;
- test modes;
- sensitivity setting.
Detector selection
Purchasing a sensor confuses not only its characteristics and functions, but also the manufacturer. Similar elements of security alarms are produced in many countries, so the market is replete not only with domestic, but also with foreign samples. The difference can only be seen upon close examination. For example, some foreign manufacturers may not take into account when developing window designs that were installed in the Soviet era.
They have a number of characteristics:
- a wooden frame can deform over time, which will transmit waves from broken glass differently than from modern plastic double-glazed windows;
- the wooden window has a small vent, which also affects the acoustic data;
- standard designs have a certain glass thickness;
- installation of glass in the opening was carried out using glazing beads, the cracks were sealed with putty, which eventually loses plasticity and distorts the sound when broken;
- glass, which has served for more than 10 years, has scratches and various irregularities in its structure, which are caused by natural phenomena.
In terms of functions and characteristics, modern domestic sensors are in no way inferior to foreign counterparts. In any case, some factors, such as room acoustics, may have been allowed to be simplified during production. Cost and installation of foreigndetectors are in some cases much more expensive.
Installation
Installation of different types of glass break detector is different, but important requirements remain. The main one is the correct choice of installation location.
- The detector must be in the zone of visibility of the protected glass, and its microphone must be directed directly at the object.
- The distance to the object should be no more than 3.6 meters. Even if a tester check shows that the system works at a greater distance, there is no guarantee that the device will pick up the sound well when the acoustics of the room change.
- Curtains on the window may prevent the item from working properly. Therefore, it is desirable to install it behind the curtains and at close range.
- The distance from the floor must be at least 1.8 meters.
- The detector should not be mounted on the same wall as the protected object.
- Sensor operation will be ineffective in high noise environments.
- Periodically, you should check the element for performance, creating false noises.
Checking the detector
To make sure the device is positioned correctly, a preliminary check will help. 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 must be placed at the far end of the glass from the detector. If the sensitivity of the element is high or, conversely, insufficient, you can adjust it.
So, we found out what the principle of operation of glass break sensors is. Now the choice is yours!
