IF your kids easily become bored while watching the television or listening
to music a smart toy may help to maintain their interest. The toy, which is
controlled by signals hidden in the sound, will respond to events on the TV or
dance around to the music.
The technique of hiding control signals in sound has been developed by
Scientific Generics, based at Harston near Cambridge. 鈥淲e can use the existing
infrastructure, putting data in TV sound, over a public address system or a
music CD, or in an e-mail or an MP3 file,鈥� says Ian Hosking. The company is
patenting the technique, which it calls 鈥渋ntrasonics鈥�.
The idea of controlling devices with sound is not new. Some early television
remote controls emitted ultrasonic bleeps. But they were unreliable. Traffic
noise could switch off the television, and the ultrasound often upset household
pets.
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In the new system, coded control signals are spread over a wide range of
frequencies, but they are too faint to be audible on a normal domestic sound
system. The technique is adapted from spread spectrum technology, which the
military developed for more secure radio communications.
The toy needs little more than the ability to decode the signals and to
respond to them. 鈥淭he receiver is just a microphone, battery and single-chip
decoder, which costs very little,鈥� says Hosking. 鈥淭here is nothing to plug in or
set up. I call it plonk and play.鈥�
Acoustic control is an alternative to wireless and infrared remote control.
Unlike the frequencies used by radio remote controls, which are licensed by the
government, anyone can use sound frequencies. And low-frequency sound is
less likely to be blocked by pieces of furniture than infrared. The technology
can be used with ultrasound at frequencies of up to 100 kilohertz.
To demonstrate the technology, Scientific Generics has made a toy that joins
in with action on the television. In addition to the entertainment potential of
a toy that acts out the part of cartoon characters, the company says the
technique has potential as a powerful educational tool. Retailers could also use
it. The soothing background music in your local superstore could be changing
prices on smart labels attached to goods on the shelves.
The company鈥檚 patent application also talks of using coded sound from four
beacons to control the position of a remotely operated vehicle. The patent says
that vehicle鈥檚 position can be fixed with an accuracy of 1 metre. The same
system, using ultrasonic frequencies, could also guide divers underwater.
