MOSQUITO

A device which blasts out a high-pitched noise that only teenagers can hear is being used to stop hoodie-wearing youths hanging around outside shops. The machine, which is hidden within the lights of corner shops, uses ear-splitting ultrasonic soundwaves. It is being hailed as the answer to clear away underage drinkers and vandals from the doorways of late-opening stores. The device, called the Mosquito, has a range of 20 to 30 metres and emits a piercing sound only clearly audible to under-20s. The sound is said to be "extremely unpleasant", but not harmful.

Inventor Howard Stapleton, of Compound Security Systems, Cambridgeshire, said he came up with the idea after reading about hearing levels changing with age. Scientists say the head, ears and auditory canals of children are shaped differently from those of adults, allowing greater amplification of high-frequency sounds. A police spokesman said, "There's a lot of concern about anti-social behaviour. If this is a way of stopping that, we'll be looking into it with interest." The new device's high-frequency electronic pulses are produced by a tone generator which is fitted with a siren horn similar to the ones used in car security alarms and smoke detectors.

It emits bleeps at half-second intervals and has a range of between 20 and 30 metres. It only affects youngsters because their hearing is more acute than adults. The box is similar to an underground gardening alarm which is inaudible to humans, but stops moles digging up their lawn. It is plugged into the mains and controlled by a timer set from inside the shop. It can be set to when older schoolchildren are most likely to hang around, automatically coming on between noon and 2pm, 3pm and 5pm, and 8pm and 11pm. (Source: Sunday Mirror)

Mosquito alarms have been introduced in Derby to combat anti-social behaviour depite there being human rights and health and safety issues The small devices have been used to disperse large gangs of youths who have gathered and intimidated passers-by. The alarms, which cost about £500, let out a high-frequency shrill noise, which, due to a natural reduction in hearing sensitivity, cannot generally be heard by people older than their early 20s.

Derby Community Safety Partnership and businessman Mike Matthews, who have both bought the alarms, said that they had proved "hugely successful". They have been used by the partnership in Spondon and the Market Place, and Mr Matthews has fitted them at McDonald's restaurants which he owns in St Peter's Street and at Markeaton Island. The partnership's anti-social behaviour manager, Craig Keen, said that the organisation had bought four of the devices and had used them in Spondon and outside the Tourist Information Centre in Derby.

He said, "It's not a painful noise but it's a bit of an irritant. They say it's like a mosquito buzzing in your ear. You put it on for about 20 minutes and young people tend to get fed up with it and move on. It seems they've done the trick but they're only a short-term measure. We don't use them a great deal because they're not a permanent solution and we're more in favour of having people on the ground providing a visible presence." (Source: Derby Evening Telegraph, Apr/07)