Intruder alarms consist of various electrical components which connected through contacts and sensors. They detect movement like opening of windows and doors. This then triggers a loud alarm to alert people of unauthorized entry.
The intruder alarm usually noticed when you shut a window or door. This contact is then detected by a door or window sensor. They then alert a control panel through a sensor. The control panel is where you can activate or deactivate a system. This is mostly done through a numbered code. If a code is not entered, the alarm sounds. However, in some cases, one can use a smartphone to remotely turn off the system.