Home security system

Τίτλος

Home security system

Θέμα

Burglar alarms

Δημιουργός

Phinikarides, George

Πηγή

Higher Technical Institute

Το πλήρες κείμενο είναι διαθέσιμο από το Υπουργείο Ενέργειας, Εμπορίου Βιομηχανίας και Τουρισμού.

Εκδότης

Library of Cyprus University of Technology

Ημερομηνία

1999

Συνεισφέρων

Lamprianidis, Diomidis

Δικαιώματα

Απαγορεύεται η δημοσίευση ή αναπαραγωγή, ηλεκτρονική ή άλλη χωρίς τη γραπτή συγκατάθεση του δημιουργού και κάτοχου των πνευματικών δικαιωμάτων.

Μορφή

pdf

Γλώσσα

en

Τύπος

text

Αναγνωριστικό

EED0711

Σύνοψη

The increasing crime in every country is mostly due to the intrusion of burglars in either domestic commercial or industrial buildings. The intruder may be an individual who seeks valuable things and who follows more or less common procedures to enter a building. In other cases, the intrusion may be done on an organised manner with professional participation which may be able to break and by-pass many sophisticated burglar alarms.
1. The intruder or burglar Alarm
There are various types of security systems that their aims are to:
i. Discourage the intruder to break in
ii. Give an early warning alarm before the intruder gets in the building
iii. Give warning alarm when the intruder has entered the building after overcoming other alarm circuits
iv. Give warning if precious items are removed from their position
The design and contraction of the intruder alarm system is often so complicated and sophisticated as to ensure reliance in case of the system being overcome. As intruders have managed to de-activate a system, the manufacturers seek for new approaches which are always more and more complex.
These solutions are usually kept as top secrets of the company and so no specific information are released concerning the construction and internal operation of the systems. Neither the technical operation of the detectors nor any other characteristics are released to everybody for obvious reasons.
2. Main parts of a security system
a) Main Control Unit
b) Sensors
c) Warning Devices
a. Main Control Unit
The primary part, "brain" of an Intruder Alann System is the Main Control Unit. The MCU that is a CPU based electronic device that accepts signal from various detectors and gives signal for a siren to go off or informs a predefined person (i.e. the police) through a modem. Usually the control unit is a multifunction adapter that allows except from the supervision, arming, disarming and programming of the system. The control panel is in a metal box to protect the electronics and is often out of sight.
b. Sensors
The sensors are the most sensitive elements used for the detection. The detectors usually have Normally Open (NO) and Normally Close (NC) contacts, which enables them to be connected in series or in parallel and in every case the circuits are continuously monitored for a malfunction or external unauthorized influence.
The sensors detect signals due to the presence or action of the intruder and
they are of the following types:
• Microwave Doppler detectors
• Ultrasonic Doppler detectors
• Standing wave Ultrasonic detectors
• Acoustic Detectors
• Passive Infrared detector
• Pressure Deferential detectors
• Capacity Volume detectors
• Vibration detectors
• Beam Interrupt detectors
• Capacity Proximity detectors
• Glass Breaking detectors
• Seismic detectors
Most of those incorporate additionally an anti-tamper device, which gives alarm if someone tries to destroy a detector. The next section is a brief explanation on how some of the most common types of detectors and sensors operate.