There are several different types of door alarm system. One may be a wireless or wired component of a larger alarm system designed to signal a central command module in the event that the sensor is triggered. Alternatively, it could be an independent, battery-powered unit with a built-in siren that sounds on the spot when a secured door is opened. Either way, a door alarm provides instant notification that a doorway has been breached.
If you are installing a full wireless or hardwired security system, securing the entry points to your home, including doors, will be one of the first orders of business. Likewise, self-contained door alarm systems work well to alert you in case a small child or special needs person wanders out through a door they shouldn't be.
Additionally, a door alarm offers a line of defense against night or daytime home intrusion, while other alarms are designed to monitor a pool gate to prevent water accidents.
Consisting of a magnetic sensor, a door alarm is basically two parts, each of which connects to a door and the immediate frame, respectively. With the door shut and the system armed, the magnets create a seal. When the door is opened, the alarm sounds. Features may include on/off switch, auto reset, delay and programmable keypad.