printer friendly version

Understanding outdoor terminology

Do not let geek speak bamboozle you.

“It takes a lot more than just a warning sign to keep criminals out of your property, however, the fight against crime has been given a major boost with the use of outdoor detection PIRs,” says Kenny Chiu, marketing manager of Elvey Security Technologies. The new generation of outdoor detectors provides heightened detector performances 24 hours a day.

Knowing what to look for in your outdoor detector is paramount in finding a balance between effective detection and false alarm prevention. Know the terminology that could assist you to improve your outdoor detection and increase your peace of mind and minimise false alarms.

Intelligent AND logic: By utilising a pyre-element, it creates a configuration area consisting of 94 high density detection zones. Also the AND detection pattern technology requires both detection areas have to be activated in order to generate an alarm condition making it more tolerant to false alarms caused by small animals or pets.

Advanced temperature compensation logic: At a higher ambient temperature, the temperature difference between the background and a human body will be reduced. In this case the PIR could fail to readily detect a human body. With conventional temperature compensation functions, the sensitivity of detector must be set higher at 35°C than the sensitivity at 25°C (normal temperature) in order for the detector to offer a stable performance. However, with this setting, the sensitivity of the detector is excessively high at 40°C or over, which could lead to various problems. To overcome this drawback, advanced temperature compensation logic allows the detector’s sensitivity to automatically drop at 40°C or higher so that the detector can perform more reliably within a wider ambient temperature range.

Summer night compensation logic: During summer evenings and nights, areas which are in shade can create an environment where the difference between human body and the surrounding ambient temperature can be at its lowest point. This logic addresses this issue by measuring the luminance levels and the changes in the environment.

The integration of temperature and additional luminance analysis provides the product the ability to more accurately assess true environmental conditions and sharpens the sensitivity as the environmental conditions require. This combination greatly reduces the potential for missed alarms, whilst maintaining stability.

Vegetation sway analysis logic: Dense vegetation could trigger false alarm with strong wind and in a thunderstorm, the vegetation sway analysis logic monitors wave changes at all times and automatically cancels the signal caused by swaying grass when it determines the increase of this distinctive wave change.

Double conductive shielding against unwanted light disturbances: Visible light disturbance protection will prevent a false alarm when a 60 W halogen lamp is turned on close to the detector. No false alarm is triggered even when a car flashes its headlights at the detector at a distance of 30 cm (If a car passes through the detector range, of course, the exhaust heat of the car will trigger the alarm). Also no false alarm will be triggered by sunlight up to an illumination of 100 000 lux. False alarms are most likely caused when early morning or evening sunlight pours into the room, and enters the field of view of the PIR either directly or by reflection. In such a case, however, the illumination reaches only about 50 000 lux. This prevents a false alarm, due to double conductive shielding.

Share this article:

Further reading: