A glass break detector is a sensor used in electronic burglar alarms that detects if a pane of glass is shattered or broken. These sensors are commonly used near glass doors or glass store-front windows to detect if an intruder broke the glass and entered.

Glass break detectors usually use a microphone, which monitors any noise or vibrations coming from the glass. If the vibrations exceed a certain threshold (that is sometimes user selectable) they are analyzed by detector circuitry. Simpler detectors simply use narrowband microphones tuned to frequencies typical of glass shattering, and react to sound above certain threshold, whereas more complex designs compare the sound analysis to one or more glass-break profiles using signal transforms similar to DCT

Discrete cosine transform

A discrete cosine transform expresses a sequence of finitely many data points in terms of a sum of cosine functions oscillating at different frequencies. DCTs are important to numerous applications in science and engineering, from lossy compression of audio and images A discrete cosine transform...

 and FFT

Fast Fourier transform

A fast Fourier transform is an efficient algorithm to compute the discrete Fourier transform and its inverse. "The FFT has been called the most important numerical algorithm of our lifetime ." There are many distinct FFT algorithms involving a wide range of mathematics, from simple...

 and react if both the amplitude threshold and statistically expressed similarity threshold are breached.

Also see

• Westminster Group
• ADT Security Services
  ADT Security Services
  ADT Security Services, originally American District Telegraph, now also known as simply ADT, is a division of Tyco International and a worldwide supplier of electronic security systems, fire alarm systems, communication systems, and integrated building management systems.-History:There were many...
  
  
• Chubb Locks
  Chubb Locks
  Chubb Locks is a brand name of the Mul-T-Lock subsidiary of the Assa Abloy Group, which manufactures high security locking systems for residential, secure confinement and commercial applications.-History:...
  
  
• Yale (company)
  Yale (company)
  Yale is a lock manufacturer owned by Assa Abloy. It is associated with the pin tumbler lock, which is often known as the Yale lock.- History :...
  
  
• Broadsword Security Services
• Business Technology Association
  Business Technology Association
  The Business Technology Association is an international not-for-profit trade association serving independent dealers, value-added resellers, systems integrators, manufacturers and distributors in the business equipment and systems industry...
  
  
• Westminster Group
• Burglar alarm
  Burglar alarm
  Burglar , alarms are systems designed to detect unauthorized entry into a building or area. They consist of an array of sensors, a control panel and alerting system, and interconnections...
  
  
• Chubb Electronic Security
  Chubb Locks
  Chubb Locks is a brand name of the Mul-T-Lock subsidiary of the Assa Abloy Group, which manufactures high security locking systems for residential, secure confinement and commercial applications.-History:...
  
  
• Security lighting
  Security lighting
  In the field of physical security, security lighting is often used as a preventative and corrective measure against intrusions or other criminal activity on a physical piece of property. Security lighting may be provided to aid in the detection of intruders, to deter intruders, or in some cases...
  
  
• Audio Analytic
  Audio Analytic
  Audio Analytic is a Cambridge, UK company that is currently developing a patent-pending sound recognition software framework.-History:The company was formed by Dr. Chris Mitchell in August 2008 after winning a national fellowship...