A Glassbreak detector is a sensor used in home security systems to detect if a pane of glass is shattered or broken. These sensors are commonly used near glass doors or glass store-front windows. They are great backup protection to a perimeter defense consisting of window magnetic contacts. Because an intruder can potentially break a glass window and crawl through the opening without opening the window a glassbreak detector can stop the thief in their tracks while their feet are still outside your home. Motion detectors are also good backup protection but can not be used obviously while family or pets are roaming through the protected area. Glassbreak detectors come in both wired and wireless versions as well as surface or recessed mounting.
Glass break detectors use a microphone, which monitors any noise or vibrations coming from glass within a door or window. If the vibrations exceed a certain threshold (that is sometimes user selectable) they are analyzed by the detector’s circuitry. Simpler detectors have evolved over the years from simple microphones tuned to frequencies typical of glass shattering to today’s complex designs that compare the sound input to one or more glass-break profiles using signal transforms and react if both the amplitude threshold and statistically expressed similarity threshold are breached. The days of jingling car keys or rattling windows due to a storm don’t fool these sensors.