Smart Dust is a cloud of tiny computers that gather data and send it to a central computer. They are so small that a conventional microchip looks monstrous in comparison. Smart Dust might, for example, operate as a squadron of miniature medical sensors that explore the interior of the human body in order to, say, better understand the pathogenesis of diseases.

These tiny computers are equipped with sensors, connected wirelessly with each other and co-ordinate their activities autonomously. Sounds futuristic? It is. Smart Dust doesn’t exist yet, but development work is well under way. Kristofer Pister, a professor of electrical engineering and computer science at the University of California Berkeley, came up with the idea 20 years ago. He went on to conduct research into the technical possibilities and tried to put the Smart Dust into practice with the startup Dust Networks that he has since sold.

Smart Dust Technology: Tiny Lenses and Circuit Boards

A few weeks ago IBM unveiled a circuit board the size of a grain of salt (see diagram) that is home to a solar cell (the power supply), a processor with several hundred thousand transistors, a main memory and a module for optical communication by LED. Tiny though it is, its computing power is equivalent to that of a 1990 PC and enough to perform its task reliably. Fixed to objects, it identifies them unambiguously. They can then be tracked electronically once special reading devices have registered them at transshipment centers.

Even smaller is possible. For more than a decade the electronics manufacturer Hitachi has marketed a wireless module with an antenna and an edge length of 0.15 millimeters. Smaller still, just a tenth of a millimeter in diameter, is Stuttgart University’s optical lens for a nano-camera that photographs biological processes at the cellular level. Tiny components like these are already, at least as far as their size is concerned, close to future technology.

Smart Dust computers are projected to be yet smaller – so much so that critics are afraid that Smart Dust could become dangerous. Small and invisible, these tiny devices might intrude anywhere unnoticed, gathering data or even posing a health threat. But Pister focuses more on the benefits: “Smart Dust makes an exceptional bandwidth of applications possible. It can be distributed across a region to record data for meteorological or geophysical research. It can be used to take measurements in dangerous or hot environments where wired sensors are unusable or lead to measurement errors.”

Smart Dust Helps Conserve Energy

Tiny light and temperature sensors could also lead to totally new ways to save energy, says Jan Rabaey, a professor of electrical engineering at Berkeley and a colleague of Pister’s: “Smart Dust is applied to walls as a special coating and records brightness and temperature.” A Smart Home system uses this data to control heating and lighting. “These mini-sensors could draw their energy from, say, vibration that wind transfers to the walls of a house,” Professor Rabaey says. Using special circuits, electricity can be generated from vibration. He estimates that lighting and heating facilities optimized in this way could reduce carbon dioxide emissions by around 30,000 tons a year in the United States alone.

So far, however, nowhere near all of the technical problems, which stand in the way of these kinds of mini machines achieving marketability, have been solved. It is not yet clear, for example, how Smart Dust can be recaptured. To do so it must identify itself wirelessly and at the same time be able to move by itself because it will mix with other particles and might end up in large quantities in dust filters and garbage cans.