WHO needs computer mice or data gloves cluttering up our desks, asks a team at MIT's Media Lab. Instead, they have created a "sensory tabletop" that keeps track of your hand as you move it around. But rather than being limited to two dimensions, the table can accurately detect the motion of your hand in three dimensions.

Physicist Neil Gershenfeld wants computer users to enjoy their technology built into attractive furniture. "So instead of it being your job to find the mouse, it's the table's job to reach out and find you," he says.

Gershenfeld developed the new system with the help of his former student Josh Smith. Electrodes build into the surface of the table induce tiny currents of the order of nanoamps in your hand. Your hand in turn, induces detectable currents in the coils embedded in the table top.

From the distribution of current in coils across the table, mathematical algorithms calculate where your hand must be in 3D space to create such currents. In this way, the technology could be used to control 3D special effects or computer-aided design software.

The technique mirrors one used by geophysicists, who face a similar problem-but the other way up. By sending electric or acoustic pulses into the ground, they can then measure the pulses that return and attempt to use these to describe the matter beneath the surface. But it's no easy task. "Supercomputers grind away for weeks on these problems," explains Gershenfeld.

But the MIT team have refined their algorithms so the table sensor works on low cost computers. Their next step is to develop the system so that the sensor table can generate a 3D computer image of the hand above it.

Author: Duncan Graham-Rowe, Boston
New Scientist magazine, issue 6th March 99

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