| The sonic teenager deterrent
London, Feb. 16: As a form of revenge against disruptive youth, it is almost too sweet ' a device that annoys teenagers so intensely they have to disperse and loiter somewhere else.
Police have given their backing to a gadget that sends out an ultra high-pitched noise that can be heard only by those under 20 and is so distressing it forces them to clutch their ears in discomfort. Eventually, they can stand it no longer and have to move on.
But because the body’s natural ability to detect some frequency wave bands diminishes almost entirely after 20, adults are completely immune to the sounds.
The sonic teenager deterrent, nicknamed the Mosquito because of its sound, has proved so successful in warding off gangs from trouble spots that it has been endorsed by the police and local authorities.
The black box, which can be attached to the outside wall of shops, offices and homes, sends out 80-decibel bursts of pulsing sounds at up to 16khz. It sounds to youngsters like a demented insect or a very badly-played violin.
But for adults it is hardly detectable. What is more, shop owners can control the strength of the signal as the problem of loitering youths ebbs and flows ' and it does not penetrate indoors.
The system was the brainchild of Howard Stapleton, a businessman and former electronics apprentice at British Aerospace, who was sick of youths hanging around outside his local shop and intimidating customers.
He remembered visiting a factory run by his father when he was 12 and finding the noise unbearable even though the adults with him were unmoved. He was told the high frequency was perceptible only to the ears of youngsters.