Electronic teenager repellant and scraping fingernails, the sounds of Ig Nobel success

Alok Jha, science correspondent
Friday October 6, 2006
The Guardian

It's a device with a variety of practical applications; an ingenious gadget that disperses gangs of loitering teenagers by emitting a piercing shriek only they can hear. Not the pinnacle of science, perhaps, but high enough to win the Welsh engineer who designed it an award from Harvard.

Howard Stapleton today receives the 2006 Ig Nobel award for peace, joining a prestigious group of previous British winners of prizes that are becoming nearly as coveted their more high-minded Nobel cousins. The Ig Nobels celebrate the quirkier side of serious scientific endeavour, according to Marc Abrahams, the man behind them, honouring "achievements that first make people laugh, and then make them think".

For Mr Stapleton, of Compound Security Systems in Merthyr Tydfil, south Wales, the accolade came for his electronic teenager repellant, called the Mosquito.

The Mosquito exploits an ageing effect that sees our ability to hear high frequency sounds dwindle as we get older. In our teens, we can typically hear sounds ranging from 20Hz to 20kHZ, but with age, the highest frequencies we can hear drops, sometimes to 18kHz or less.

"We discovered that, even at relatively low volumes, the right frequency noise would only be heard by 25s and below and it was highly annoying after five minutes," Mr Stapleton said. "The Mosquito was born."

Tests of the £580 unit at a local Spar shop in Barry, south Wales, last year were declared a success when teenagers that congregated outside the premises pleaded with the owner, Robert Gough, to turn it off. Older customers were reported to be oblivious to the high-pitched shriek. The box, mounted on a wall outside the shop, was programmed to emit an 80-decibel pulse of high frequency sound that cleared an area up to 15 metres away....