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A novel motion detector developed by the two Fraunhofer Institutes "Applied Polymer Research IAP" in Potsdam-Golm and "Computer Architecture and Software Technology FIRST" in Berlin can now provide more security.

A special coating enables window panes or glass doors to recognise movements. Has anything changed outside the pane? Is somebody creeping up? If so, the window sends a warning to the security company.

How's it done? "The glass is given a fluorescent coating," explains Dr. Burkhard Elling, Group Leader at the IAP. "The coating contains nanoparticles that convert light into fluorescent radiation." The underlying principle? The invisible light of a UV lamp illuminates the window panes and generates a layer of fluorescent radiation.

This is directed to the edges of the window, where sensors detect it. If several sensors are placed on all four sides of the frame, the data can be used to decide how quickly and in what direction an object is moving. The sensors are also capable of estimating an object's size.

Is it just a small animal, like a bird, or is it a person? The alarm's sensitivity can be set. For example, at a level where bird-sized objects do not trigger the alarm. Nor do the sensors respond to the lights of a passing car. The researchers at FIRST have developed a program that is capable of interpreting various light signals. This enables the system to distinguish easily between the frequency of a UV lamp and the gradual change of a passing headlight.

Further information: www.iap.fraunhofer.de