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Shaky legs

A new vibrating table can rearrange objects without touching them

A "magic table" which can rearrange objects without touching them has been developed in California. The invention could soon lead to tables that set themselves, bar tops which deliver their own drinks and better automated industrial processes.

Dan Reznik's unique 'Universal Planar Manipulator' moves an object placed on its surface without affecting other objects using nothing more than vibrations.

And the UPM is not very noisy, says Reznik, a graduate student at the University of California in Berkeley, California. "There's no up and down movement, otherwise it would make the surface act like a speaker."

The surface vibrates horizontally thanks to four vertical, flexible supports. These are like table legs with motors attached. The frequencies applied to the surface are fairly low so the vibration is not very noticeable, says Reznik. At the very most it would feel like a massage device.

Precise movement

Very selective and precise movement is produced by superimposing three frequencies. "A single horizontal surface is capable of moving an individual object while keeping the other objects on the surface still," he says.

Two frequencies of 35 and 70 Hertz produce a conveyor belt effect, "like an inchworm," says Reznik. A third frequency of 29 Hertz creates rotational motion like a pivot.

By varying the phases of the three it is possible to control very precisely how different parts of the plate affects objects on its surface. A null frequency can be achieved where no motion occurs.

"So, perhaps your desk is a little messy and you want to tidy it up," says Reznik. At the press of a button the desk moves your clutter to its usual place using nothing more than the vibrations of the desktop.

He also envisages self-setting tables but it will have to be dinner for two. According to Reznik the number of objects it can manipulate simultaneously is limited. So far he has managed to control eight objects independently at the same time, but he thinks more than ten would be difficult.

The UPM is one part of the Distributed Manipulation project at Berkeley. Other ways of moving objects across surfaces which are being investigated include arrays of tiny hairs, rollers, electron magnets and even air nozzles.

Correspondence about this story should be directed to mailto:latestnews@newscientist.com?subject=Shaky legs

1429 GMT, 5 October 2000

Duncan Graham-Rowe

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