- Security house alarms that use motion sensors work by placing sensor transmitters around the house, usually by main entrances like front and sliding doors. The motion sensors work by detecting infared heat from the human body. The body transmits a certain wavelength of heat that the sensors are configured to detect. Once a disturbance is detected, the motion sensor sends a signal to the main control keypad.
- Some alarm systems employ a circuit system. Wires are usually placed around main doors and windows. One sensor is placed on the door, and the other on the frame. When they are touching or parallel to one another, then the electric circuit of the sensors are either open or closed. When the door or window opens and the circuit then becomes closed or open, it triggers the alarm to go off.
- If an alarm system is active and needs to be deactivated (for example, a person is coming home from grocery shopping and the alarm is active), the owner must deactivate the alarm by using a set code that is typed into the control keypad. The owner has a preset amount of time to enter in the correct code before the alarm goes off.
- Once the alarm on most house alarms are activated, they can emit a loud beeping or screeching noise. The purpose of this is to alert the homeowners of a possible disturbance or to alert the surrounding neighbors in case the homeowners are out of town or unable to get help. The alarm also usually scares the intruder away from the home, as they do not want to be caught by the police.
- Many house alarm systems are connected to a telephone jack so it can automatically call the police or alarm company once it is activated. If it calls the alarm company, a representative usually first tries to call the owner's phone number and then calls the police. Automatic dialing to the police ensures that the homeowners were not harmed (or if they were, allows for the police to call for an ambulance) during the intrusion and allows them to attempt to catch the intruder in the area.
