Ultimate Spy Source: University of California November 20, 2000
If Kristofer Pister has his way, we will never think
about dust in quite the same way again. Pister is leading a team of
researchers at the University of California at Berkeley that is
developing tiny, electronic devices called "smart dust," designed to
capture mountains of information about their surroundings while
literally floating on air.
If the project is successful, clouds of smart dust could
one day be used in an astonishing array of applications, from
following enemy troop movements and hunting Scud missiles to detecting
toxic chemicals in the environment and monitoring weather patterns
around the globe.
The idea behind smart dust is to pack sophisticated
sensors, tiny computers and wireless communicators onto minuscule
"motes" of silicon light enough to remain suspended in air for hours
at a time. As the motes drift on the
wind, they can monitor the environment for light, sound, temperature,
chemical composition and a wide range of other information, and beam
that data back to a base station miles away.
Pister, an associate professor of electrical engineering
and computer science at UC Berkeley, said he came up with the idea for
smart dust eight years ago at a conference on future technology. "I
realized that sensors, computers and communications were going to
shrink down to ridiculously small sizes," he said. "So why not package
them into a single, tiny device?"
Pister submitted a proposal to the federal Defense
Advanced Research Projects Agency, a branch of the Defense Department,
which agreed to provide about $1.2 million over three years to fund
the project. Each mote of smart dust is composed of a number of
microelectromechanical systems, or MEMS, wired together to form a
simple computer.
MEMS are made using the same photolithographic
techniques used to make computer chips. Once perfected, they are
relatively easy and inexpensive to mass-produce. But unlike computer
chips, which are solid, MEMS contain moving parts. Patterns are etched
with light into a silicon wafer to create
structures such as optical mirrors or tiny engines.
Each mote contains a solar cell to generate power,
sensors that can be programmed to look for specific information, a
tiny computer that can store the information and sort out which data
is worth reporting, and a communicator that enables the mote to be
"interrogated" by the base unit. Later versions may also contain a
lilliputian lithium battery so the motes can operate at night.
While much of the technology used to develop smart dust
already exists, the UC researchers are breaking new ground by
integrating these systems into remarkably small, self-powered
packages.
Pushing the Limits
"We are pushing the limits of miniaturization,
integration and power management," said Brett Warneke, a graduate
student in electrical engineering working on the project.
In one experiment to demonstrate the viability of the
concept, researchers deployed a golf ball-sized device on Twin Peaks
in San Francisco that measured weather conditions in the area -
temperature, light, barometric pressure and humidity - and beamed that
information back to a base station in Berkeley, more than 13 miles
away.
So far, the smallest device the UC researchers have
developed is 62 cubic millimeters - about the size of a pea - but
Pister expects to shrink the devices to a nearly microscopic cubic
millimeter by next summer. At that scale, they would be truly like
dust: small enough to remain suspended in
air, buoyed by the currents, sensing and communicating for hours.
One of the biggest hurdles the UC researchers face is
building a mechanism that can survive on extremely low power but is
still capable of sensing, sorting and sending vast amounts of
information. For that reason, they have designed a computer operating
system called Tiny OS that can function
on a mere 512 bytes of RAM - about the amount of processing power
found in a toaster.
The UC researchers are also experimenting with an
ingenious optical communicator called a corner-cube reflector, which
enables the motes to communicate while expending virtually no energy.
Pioneered at the University of California at Los
Angeles, the reflector is essentially a tiny, hinged mirror that can
flash millions of Morse code-like signals per second. When a smart
mote is illuminated by a laser fired from the base station, the
station can "read" the code reflected in the twitching mirror. The
mirror itself is powered by electrostatic energy, the force that makes
your socks cling together when they come out of the dryer.
Smart dust devices are now capable of communicating only
with a single base station, but will eventually be able to share
information with each other.
Such a system of "massively distributed intelligence"
will vastly increase their ability to organize and communicate
information.
"They will be able to do things collectively that they
can't do individually, just like an ant colony," Warneke said. "An
individual ant isn't very smart, but collectively, they are very
smart."
Researchers are exploring a number of methods for
deploying smart dust. One involves the use of tiny, unmanned aircraft
that would spray motes over an area like a miniature crop duster and
relay the resulting information back to a base station. MLB Co., a
Palo Alto firm that develops experimental
aircraft, has already built such a plane - an 8-inch radio-controlled
aircraft equipped with a video camera that can stay aloft for 18
minutes at a speed of 60 mph.
MLB's "micro air vehicle" could be useful in a
battlefield situation where low clouds impeded satellite surveillance.
The tiny, unmanned plane could soar undetected above the battlefield,
disperse a swarm of smart dust and begin relaying a stream of data
about the movement of enemy troops and
equipment.
The UC researchers are also exploring ways to prolong
the time smart dust remains airborne by adding "wings" like those on
maple seeds. A cubic-millimeter-sized mote dropped at 30,000 feet
would normally take five hours to reach the ground. By attaching
wings, the researchers hope to extend that
period two- or three-fold.
Other researchers are attaching tiny legs to the motes
to create so-called microbots or smart insects. Instead of wafting
aimlessly through the air like dust, microbots could be programmed to
perform specific tasks, such as crawling through a collapsed building
to search for warm bodies.
"Smart dust is like the brain, and we're building the
body," said Richard Yeh, a graduate student researcher specializing in
microrobotics who is working on the smart dust project.
Yeh and his colleagues have already developed the basic
components of a smart insect - tiny, jointed members, which function
as legs, and minuscule motors, the equivalent of muscles. All that
remains is to connect the components to a mote of smart dust, a step
Yeh expects to accomplish within weeks.
Although the smart dust research is supported by the
Defense Department, its proponents see many nonmilitary applications
for it, many for motes that would stay in one place.
Crunchless Cap'n Crunch
They could be used to detect fires and earthquakes,
tailor the climate in office buildings to suit the preferences of
individual workers, and monitor product quality from factory to
consumer (a mote of smart dust could tell, for example, if a box of
Cap'n Crunch had been exposed to high humidity, and lost its crunch,
or if a crate filled with delicate electronic components had been
dropped).
Like many other new technologies, smart dust clearly has
the potential to be used for nefarious purposes. Foreign governments
(or our own), terrorist organizations, criminals and industrial spies
could use high-tech motes to spy.
"This is a technology of total surveillance," said
Richard Sclove, founder of the Loka Institute, a nonprofit
organization in Amherst, Mass., that studies the social implications
of technology.
"I have no doubt that there will be plenty of benign and
wonderful applications of this technology, but it's easier to imagine
the lousy ones. The CIA and the National Security Administration would
love to get their hands on this, and there's no way to control what
they do with it."
While Pister acknowledges the possibility that smart
dust could be misused, he says the potential benefits of the
technology "far, far outweigh" any risks.
"You can find harmful effects in everything," added Yeh.
"But the threat is small. If a rogue state wanted to use them to spy
on us, they could do it, but not much more. They probably couldn't
carry enough poison or gas to do much damage."
The specter of millions, or even billions, of electronic
motes drifting around the globe has also raised concerns about the
potential ill effects on the environment and health.
But Pister dismissed such concerns. "Even in my wildest
imagination, I don't think we'll ever produce enough smart dust to
bother anyone," he said. "Most of these materials are not
environmentally harmful. Essentially they are made out of sand, and
that's not toxic."
Potentially, the most dangerous element of a smart dust
mote would be the lithium battery, Pister says, but its minuscule size
would pose little risk.
"A small town throws away more batteries per year than
we can distribute across the entire universe," he said. "It's really a
question of trade-offs. If you can sprinkle a few ounces of battery
over a rain forest and thereby get a better understanding of the
ecology, that's a trade-off worth
making."
And what if someone accidentally inhaled a mote of smart
dust? "If by ill chance you did inhale one, it would be like inhaling
a gnat. You'd cough it up post-haste. Unpleasant, but not very
likely."
GATHERING DATA ON THE FLY
Researchers at the University of California are
developing tiny, electronic devices called "smart dust" designed to
capture information about their environment while literally floating
on air. Each dust "mote" packs sensors, computers and wireless
communicators onto a tiny silicon chip light enough to
remain airborne for hours at a time. As the motes drift, they can
monitor their surroundings and beam data back to a base station.
Researchers are exploring a number of methods for
deploying "smart dust." One technique involves the use of tiny,
unmanned aircraft that would spray motes over an area like a miniature
crop duster and then relay the resulting information back to a base
station..EARLY PROTOTYPE
Smart dust ``macro-mote'' made with readily available
components.
To test their concept, researchers planted golf
ball-sized smart dust devices at Twin Peaks and on Coit Tower. Using a
modified laser pointer, the device beamed weather information back to
Berkeley.
Potential Uses
Military uses include tracking enemy troop movements
from above and detecting chemical warfare agents in the air. --
Monitoring weather conditions around the globe and detecting fires and
earthquakes are among the nonmilitary uses. -- Stationary motes could
be used to monitor the quality of products from factory to
consumer..
by Peter Kupfer
SF Chronicle Staff Writer
Department of Electrical Engineering and Computer Sciences