Glass Break Sensors
Glass break detectors (also known as audio discriminators) are used as a perimeter device. This is because the object is to catch an intruder who is attempting to enter into your home (Other detectors pick up the motion of someone walking around the interior of the home).
Glass break detector security devices listen for the sound frequency of breaking glass and wood that is cracking and splintering. However, in the past, a "single technology" glass break alarm would also sound at sneezes, lightning, squawking birds or glasses clinking together. This resulted in many false alarms.
While those devices are still available, glass break detector reviews may tend to recommend the "dual technology" device glass break alarm. They have far fewer false readings because they have to hear a thump sound first followed by a frequency hit before the alarm sounds.
Some things to consider if you are trying to make a decision on purchasing a glass break sensor:
- They are available in hard-wired and wireless models and cost between $150 and $200 retail.
- They mount on a wall or ceiling.
- They monitor an area of about 20 to 35 feet in all directions but do not hear through walls, around corners or into a room where a door is open.
- In a great room (kitchen, breakfast nook and family) setting, you can probably cover all of the windows with one device because the windows are likely to be within the 35 foot range.
- Likewise, in a living room, one device should be able to cover all of the windows.
- An unfinished basement with windows is a vulnerable spot and one glass break detector should also be sufficient there also.
- There must be a clear line of site between the sensor and the glass.
Different Types of Glass Break Detectors and Sensors
An acoustic glass break sensor which has a built-in microphone is designed to monitor for special frequencies that are heard when glass is breaking as suggested above. The reason you can cover several windows with one device is that the sensors monitor within a range of frequencies (from the infrasonic to the ultrasonic levels).
However, a seismic glass break detector is installed directly into the glass plane that is being monitored. With these, the detection occurs by sensing for unique shock frequencies. Most of the time the frequencies will be somewhere between 3 and 5 kHz. These frequencies travel along the pane, window frame and even sometimes within the surrounding paneling. Once the break is detected, the alarm will sound.
Wired versus Wireless Glass Break Detectors
A wireless glass break sensor usually provides the most flexibility mainly because you are able to place them where ever you like without worrying about connecting wire. However, interference (other wireless signals or thick walls) might pose a problem for them. This can be dealt with by making sure the sensors are placed within the recommended radius of the security system control panel. Wired models, which have to be connected to a central panel,are also available.