Acoustic glass break detectors

Glass break sensors in the security system

The glass break sensor is a device designed to detect the fact of glass breaking in the armed room and send an alarm signal to the alarm central.

According to the principle of operation, such glass break sensors are distinguished:

Acoustic glass break sensors

Acoustic glass break sensors for alarms are the most common.

The principle of operation of such devices is to analyze the spectrum of sound frequencies that occur when glass is broken. Signal processing by the sensor minimizes false alarms and increases the reliability of detection.

Acoustic sensors are easy to use, since glass break detection is non-contact — the detector does not need to be mounted on a glass surface. The main thing is to eliminate obstacles for detection. Curtains, blinds, films, weaken the sound level.

How to check if the glass break sensor is working

Checking the operation of the glass break sensor is carried out in the following ways:

• using a glass breaking simulator that simulates the real sound of breaking;
• actual breaking of a test glass object.

Checking the sensor with a broken simulator is the best option if the sound spectrum it generates corresponds to the processing algorithm of the acoustic sensor being tested. In this case, the algorithm of the glass break sensor is checked:

• first, the sensor detects a low-frequency impact sound;
• then the high-pitched sound of broken glass.

Shock contact detectors

Shock-contact glass break sensors are used less frequently than acoustic ones.

Such sensors are mounted on the glass to be monitored. They are supplemented by a signal processing unit that monitors their status.

Depending on the modification, up to 5 or up to 15 glass break sensors are connected to one unit, which can control surfaces with a thickness of 2.5 to 8 mm, including those covered with a polymer film.

This type of sensor reacts to glass breakage, as well as to cracks on its surface that do not cause destruction. This can be useful when detecting cut-outs of a piece of glazing.

Another type of shock-contact glass break sensor is an inertial magnetic contact. Its body contains a reed switch and a magnet on a movable plate.

When such a sensor deviates from the vertical plane by 20° or more, due to the deflection of the plate with the magnet, the contacts of the reed switch open.

Also, the sensor is triggered by a non-destructive impact on the glass, as well as its removal from the frame or the entire frame.

According to the method of transmitting an alarm signal to the alarm control panel, break sensors are:

1. Wired glass break sensors for alarm require cable connections during the repair phase.
2. Wireless security sensors transmit signals to the control panel via radio communication.

Like other security system devices, glass break sensors are addressable and non-addressable. In turn, addressable are both wired and wireless.

Glass break sensors from Ajax for alarms

Glass break sensors of the security system are the protection of the premises from vandals, robbers and bad weather. The Ajax line of security devices includes wired and wireless options for glass break sensors. The detectors raise an alarm when they detect two consecutive sounds: a low-frequency sound of glass hitting and a high-frequency sound of falling fragments. After detecting such an incident, system users and the security company will receive notifications.

Ajax glass break detectors do not react to extraneous sounds — barking dogs, cars, thunder will not provoke a false alarm. Ajax glass break detectors are available in two versions: a separate miniature detector suitable for installation in any interior, and a combined motion and glass break detector.

Wired glass break sensors

Ajax security system offers the following options for wired glass break sensors for the security system:

1. GlassProtect Fibra is a wired glass break detector with a glass break detection range of up to 9 m. The sensor maintains communication with the control panel at a distance of up to 2000 m.
2. CombiProtect Fibra is a wired combined motion and glass break detector in an armed room. The detector detects movement at a distance of up to 12 m, and glass breakage at a distance of up to 9 m. Communication with the central security system is maintained at a distance of up to 2000 m.

The wired glass sensors and the security control panel communicate using the Fibra protocol, a digital generation wired technology. Fibra combines the freedom of radio communication, the security and reliability of wires.

Wireless glass break sensors

1. GlassProtect Jeweller is a wireless glass break detector for alarm with a glass break detection range of up to 9 m. The battery of the device works without replacement for up to 7 years. The wireless glass break sensor maintains communication with the alarm control panel at a distance of up to 1 km.
2. CombiProtect Jeweller is a wireless combined motion and glass break detector. The motion detection range is up to 12 m, and the glass break detection range at a distance of up to 9 m. The battery works up to 5 years without replacement, and communication with the control panel is possible at a distance of up to 1200 m.

Communication between the control panel and wireless glass break sensors in the Ajax security system takes place via the Jeweler radio protocol. It is a radio technology with data encryption. In the event of an attempted jamming or interference, Ajax changes the radio frequency and informs users and the security company about it.

Features of glass break sensors from Ajax

Ajax security glass break detectors for alarms have a number of features:

1. The sensitivity of each Ajax sensor is adjustable.
2. Ajax glass break detectors verify their trips using the DualTone digital algorithm.
3. Security glass break sensors GlassProtect Jeweler and GlassProtect Fibra are equipped with terminals for connecting a third-party sensor with a normally closed contact type. It can be a detector of any kind: vibrations, movements, openings.
4. Ajax glass break sensors for alarms do not need to be disassembled for adjustment. Connecting to the security system and setting up the device takes place in the application for the phone or PC, where you can also create an automation script (set automatic closing of the shutters in case of a window break).
5. Reliable communication technologies. Jeweler — for wireless line, Fibra — for wired devices.