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Watching the outdoors

Six out of 10 South African households fear robbery and burglary more than any other crime, which is understandable given that 99% of these perpetrators are armed.

That’s according to Ingo Mutinelli, sales director of Elvey Security Technologies, who says these findings, contained in the 2012 Victims of Crime Survey (VOCS) by Statistics SA, are supported by growing demand from the public for multi-layer security systems.

“We’ve seen substantial growth in demand for external detection devices in the last few years,” he says. “People want to stop criminals before they get into their homes, hence their gravitation towards early detection devices, which will warn them in advance of an intrusion and give them enough time to call for help or barricade themselves into a safe room until the police or armed response action unit arrives.”

Of the many outdoor detection products currently on the market today, he mentions the Visonic Tower-20, an external detector with a coverage pattern of 90 degrees and a range of 12 metres. “External detectors need higher levels of reliability and stability than internal detectors. To achieve this, Visonic has embraced something called Octa-Quad technology, which can distinguish between moving people, swaying trees and bushes and small animals (up to 18 kg in mass), thereby minimising false alarms while simultaneously ensuring the effective detection of real threats.”

Octa-Quad technology makes use of eight independent passive infrared (PIR) quad detection elements, each of which boasts Visonic’s patented TMR (true motion recognition) algorithm as well as a central processing engine. This level of processing allows for an extremely high degree of accuracy in terms of separating genuine human motion from innocuous movement.

The central motion processor analyses the motion signals identified in each of the individual detectors, taking into account the time, amplitude, background temperature, speed of motion, size of target and direction of motion. It then compares the signals with those of adjacent detectors in order to ascertain the alarm’s validity.

Another feature of the Tower-20 is its black mirrored surface. “The Obsidian Black Mirror is a unique, nickel-based obsidian-like reflective surface which acts as a selective optical filter for infrared energy while virtually eliminating white light interference. It’s this technology that ensures the detector’s performance is not affected by climatic or environmental conditions.

The Tower-20 also offers anti-masking protection as a result of its dome-shaped IR perimeter shield, which allows for detection from all angles and includes a creep zone.

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