A burglar alarm system uses sensors to detect... | Information and Communication Technology 0417 | Paper 1 Mock 01 | Theory

Question 1 Report

A burglar alarm system uses sensors to detect intruders in a building.

(a) Complete the table by identifying a suitable sensor and where it would be placed.

[3]

(b) Describe how the alarm system responds when an intruder is detected. [3]

Answer

Answer Details

(a)

Location	Suitable sensor
Hallway	Infrared / PIR (passive infrared) motion sensor. [1] It detects body heat from a person moving through the hallway.
Front door	Pressure sensor (under the doormat) or magnetic contact sensor (on the door frame). [1] A magnetic sensor detects when the door is opened because the magnet separates from the switch.
Window	Magnetic switch/contact sensor or vibration sensor. [1] A vibration sensor detects the impact of glass being broken, while a magnetic contact detects the window being opened.

(b) How the alarm system responds when an intruder is detected:

The sensor detects movement, a door opening or a window being broken and sends an electrical signal to the central control unit. [1]
The control unit checks whether the alarm system is currently armed (enabled). If the system is disarmed, the signal is ignored. [1]
If the alarm is armed, the control unit activates the siren or bell to alert people nearby, and may also send an automatic alert to the security company or the homeowner's phone. [1]

A burglar alarm system uses sensors to detect intruders in a building. (a) Complete the table by identifying a suitable sensor and where it would be placed....