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Home Security Alarm Systems
Home security alarm systems are more sophisticated than most people think. They typically consist of either an alarm sensor, silent alarms, wireless alarm, or door stop alarm, combined with emergency dialers, control panels, door, window, flood, garage door sensors,
Alarm Sensors
Alarm sensors detect conventional alarm sounds from existing security systems to activate transmission of a signal to the control panel
or emergency dialer units, which then activates the system. Alarm sensors come as stand-alone units or can be used in conjuntion with
other security systems using a N/C connector.
Silent Alarms
Silent alarms plug into a light or other 110V signaling device for visual warning of an alarm condition.
By connecting the alarm to a lamp or other light fixture, the alarm will activate the appliance, creating a flashing light demonstration
to draw the attention of neighbors or other people that may be in the area when it receives a signal from the control panel.
Door Stop Alarm
Door stop alarms are used to block a door or window from being opened. If an intruder tries to open a door, a 125-decibel alarm feature
will sound and the door will jam against the alarm's wedge shape. Advanced door stop alarm models feature a movement sensor with an
adjustable sensitivity to activate the alarm if an intruder tampers with the 9-volt battery power unit.
False Alarms
The prevention of false alarms can be achieved by using a dual-technology motion detector. Dual detectors are the most common type of detector used in more sophisticated burglar alarm systems.
A dual-technology detector combines a passive infrared device and a microwave device in one small unit. The passive infrared device sees many detection zones and measures the change in background temperature as a target moves across them.
At the same time, the detector projects microwaves and measures the Doppler shift when a target moves through the protected space.
An infrared motion detector will detect movement regardless of whether the target is moving across the field of view or toward the detector. But such a detector is more sensitive to movement across its field of view. Thus, it is more prone to false alarms caused by disturbances such as a mouse or rat moving across its field of view than by movement toward it. Microwave detectors are just the opposite: more sensitive to targets moving toward them than they are to targets moving across their field of view. If a large leaf falls off a plant in a room, a microwave detector is more likely to detect the motion than is an infrared detector. But if there is movement outside a window, a microwave detector might detect it when an infrared detector probably would not.
Dual-technology motion detectors use a circuit that requires both devices to detect motion before an alarm is sounded. A bird landing on an outside windowsill might trip the microwave device but not the infrared device, so no false alarm would be transmitted.
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