Echolocation, Microphones, and Panic Buttons — How Burglar Alarm Sensors Detect Intruders

Many people install “burglar alarms” intrusion security systems in their homes and businesses, to better protect their valuables. And, for every type of home invasion and commercial theft, there’s a specific sensor that can warn authorities of the crime-in-progress. So, how does an alarm system actually work? And what different types of burglar alarm sensors are available for commercial intrusion systems?

How Alarms Work: The Basics

Alarm systems have a variety of sensors and circuits installed within their hardware to monitor the conditions of its installed environment. Whenever an alarm system is “armed” and active, it uses its various sensors to detect change in its environment. The system assumes that the environment will stay the same, so it doesn’t alarm. It’s only when a sensor detects a change in the area that it begins the alarm process, assuming the change could be from an unauthorized intrusion.

When it detects a change, the sensor notifies a central control panel — the “brains” of the installed security system — that processes the event and alerts the authorities as programmed.

There are many different sensors on the market that can detect distinct types of environmental change. The type of sensor used depends on the area in which each portion of the intrusion system is installed, and what type of change it’s supposed to watch for.

Commercial and Domestic Burglar Alarm System Sensors

Door Sensors

There are two ways in which an alarm system can identify unwanted door access.

The first requires an integrated access control system, like the one Eyewitness provides for interested clients. Individual-specific permissions control who can access what areas, when. If an unauthorized person tries (and fails) to access a secured area, then the access control system can act as an intrusion alarm system. It will send a message to the system administrator, alerting them to the unauthorized attempted access.

The second method is directly installed with the intrusion alarm system, and relies on magnets.

When an alarm system is installed, a special switch is built into doors, held shut by a magnet. If a door opens while the system is armed, then magnet will sense the movement. An internal “switch” is tripped, which triggers a notice to the central control panel.

Detector for Glass Panels and Windows

Some sophisticated microphone sensors constantly listen for breaking windows. If it hears a specific sound wave pattern that matches broken glass, the system then sends an alert to the central alarm panel.

Motion Sensors for Walls and Heavy Doors

Thieves often try to burst through physical obstacles with makeshift battering rams, like this gang of thieves that used a stolen vehicle to ram aside a barricade. Special sensors can detect shock waves within walls and doors that indicate heavy impacts consistent with forced entry.

Lasers in Open Hallways

There are both “active” and “passive” motion detectors that can sense movement within open spaces.

You can think of “active” motion detectors a bit like bats’ echolocation ability. These sensors constantly emit high-frequency sound waves inaudible to humans that reflect to the sensors at a specific rate. If the sound waves are bounced back faster or slower than usual — due to someone walking in front of it, for instance — the sensor identifies that as an intruder.

Photo sensor “passive” motion detectors are the basis of the infamous “laser dance” scene in Oceans Twelve — though they usually don’t rotate based on disco music:

These motion detectors sense a movement when an object interrupts its continuous laser beam. Don’t expect visible light beams covering your hallways, though — the wavelength at which these lasers fire is invisible to the human eye.

Emergency Situations

Intrusion systems can also feature “emergency” sensors and alerts, depending on the needs of the client.

There’s the traditional so-called “panic button.” These discrete switches are installed in an easily accessed yet unobtrusive area for employees to silently call for help and “lockdown” the facility during emergency situations. (Anyone remember the Kansas dealership hostage situation in February 2017?)

And, microphone sensors can also be programmed to trigger when it records screaming that matches panicked sound recordings in its library.

This feature could be especially helpful if set to a timer, to protect employees when working late at night or early in the morning. That way, someone would always be there to hear them scream — and subsequently alert the authorities.

Alarm systems are only limited by the imagination of the installer and the skill of the sensor’s programmer. With a good burglar alarm system set up and armed, a mouse couldn’t sneeze without the monitoring company knowing about it.

(And, if you’re looking for a custom intrusion alarm system, Eyewitness offers a completely integrated and customized security solution for businesses looking to protect their property before a break-in occurs. Contact us for an intrusion alarm demo to see how we can help you secure what’s most important to you and your business.)

Originally published at Eyewitness Surveillance.