Door Alarms

Doors can utilize magnetic contact sensors to detect when a door is opened. The sensor mechanism is housed in the switch side of the sensor and a magnet is housed in the other half. Most door alarms utilize a contact switch, which has two metallic parts that must stay in contact when the sensor is armed. In order for a door to be slid or swung open, the mechanism's metallic contacts lose contact with one another. One half of the door sensor is attached to the fixed side of the doorway, and the other is attached to the movable door. When the door is opened the two parts of the mechanism are separated and the alarm signal is sent.

These mechanisms use a strong magnet that can maintain magnetic contact even when the door is opened slightly. This makes it possible to leave a door open to allow airflow between rooms, yet still have all the protection of armed door alarms.

Electromechanical door locks are powerful electrified lock mechanisms which keep them from being opened. They are an important form of security in commercial properties but can also be used in home security systems. These systems often integrate a magnetic contact sensor so if by chance the door should be opened, an alarm would be activated.

Learn more about home security systems.