How does the motion detector work?
There are three systems available on the motion detector market. Infrared (thermal radiation), Ultrasonic (high frequency sound waves) and radars (microwaves). There are passive and active detectors. Passive means, that the sensors of the detectors pick up external infrared radiation and react to it. The detectors are referred to as active, which itself is a signal – for example ultrasonic waves – send out and pick up the echo again. Modern PIR alarm (Passive infrared detector) are relatively accurate, safe and inexpensive. That is why most detectors work with this technology. The report command is passed on by wire or radio, the electronics of the radio transmitter are powered by a 9 V battery. The monitoring area can be limited with the help of screens in front of the Fresnel lens. For this purpose, the apertures cover individual segments of the lens.
What do the designations mean?
infrared rays
are heat rays, which every living being radiates with body heat. This is why animals can also be detected by infrared sensors and trigger the detector.
Ultrasonic
are sound waves in the range inaudible to humans. The sound pulse is emitted by the transmitter and reflected by the object. The detector responds to this echo.
microwave detector
work like a radar device. A pulse in the microwave range is sent, reflected by the object and received again. Microwaves also penetrate non-metallic materials, Ultrasound and infrared do not.
Fresnellinsen
look like embossed foils and can focus infrared rays and change their direction. They ensure the fan-like division of the surveillance area.
switching capacity
is the performance – usually denoted in watts -, which the detector can switch itself. If the specified power is not sufficient for the intended wattage of the bulbs, needs a relay (electrically operated switch) be installed in between.
twilight switch
ensure, that detectors are only active in the dark. At which degree of twilight it should switch, is adjustable.
Some outdoor lights with house numbers can “think for themselves”. During the day they are switched off, at dusk they turn on 10 percent light output (number lighting) and when approaching 100 percent.
time or burn time
How long the lights should burn, after being turned on by the detector, can be set. The duration is between 10 Sek. and 10 Min.
detection range
This describes the area, which is reliably reached by the sensor. The "shadow" behind posts and plants is not monitored.