Friday, February 22, 2008

Teenager repellent

Boing-Boing has a link to an article about an ultrasonic anti-teenger device in use in Britain.

"The device works by emitting a pulse at 17-18 kilohertz that switches on and off four times a second for up to 20 minutes. Teenagers can pick it up through minute hairs in their inner ears – but those hairs tend to die off by the time they reach 25."
Don't miss the full text of the article, which has samples of the actual sound (which I can hear quite easily, though I'm supposedly too old).

1 comment:

Maggie Stiefvater said...

They're using these in the states, too, by the way -- I saw it on the news a few months ago. Apparently you can download ultrasonic/ super high pitched cellphone rings so that your teacher can't hear it. At the time I thought, oh cool . . . oh wait, don't we already have ones that vibrate?