Smart Dust Sniffers
by David Pescovitz
Richard
White (on right). (Click for larger
image.)
Photo courtesy Richard White
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In 1991, Richard
White sadly watched as homes in the Berkeley and Oakland hills burned
in a massive fire. Now, the professor in the Department of Electrical
Engineering and Computer Sciences is developing technology to help
protect the firefighters that risked their lives to protect White
and his neighbors.
White is designing chemical sensors that firefighters could wear
to warn them when deadly carbon monoxide is in the air. The inexpensive
devices are based on the Smart Dust Mote platform, matchbox-sized
sensors outfitted with their own "TinyOS" operating system
and wireless transceivers. The data the Motes gather hop from one
Mote to another, ultimately landing at a central location for processing.
Developed by UC Berkeley researchers as part of the Center for Information
Technology Research In The Interest of Society (CITRIS), the Motes
are commercially available from Silicon Valley-based Crossbow. Within
several years, CITRIS researchers expect to shrink the Motes to
a millimeter on all sides through manufacturing processes similar
to those used to fabricate integrated circuits.
White began developing the chemical sensing Smart Dust after a meeting
of the Berkeley Fire Safety Commission, on which he served for eight
years. He had brought a Mote to instigate discussion of potential
fire-related applications with the Assistant Chief David Orth of
the Berkeley Fire Department.
White
burns incense to trigger the carbon monoxide sensor. (Click
for larger image.)
David Pescovitz photo
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"We went out to his car and grabbed his firefighter helmet,"
White says. "The Smart Dust Mote slipped perfectly behind the
badge on the front of his helmet."
In recent experiments with a prototype chemical sensor and a stick
of burning incense, White and graduate student Justin Black noted
that the Mote is capable of detecting carbon monoxide almost instantly
and resets the moment the source of the gas is removed. Typical
carbon monoxide sensors, like those available at hardware stores,
take several minutes to detect the poisonous gas and more than a
quarter-hour to return to a normal state after being triggered.
Along with alerting firefighters to the poisonous gas, White believes
Smart Dust Motes could also help determine the safety of today's
firefighting gas masks.
"It's been difficult to tell how much carbon monoxide actually
seeps into masks, but the Motes are small enough to fit inside the
mask and detect the leak," White says.
Most recently,
White demonstrated a Mote that detects hydrogen sulfide, ideal for
refineries where dozens of sensors
could be installed to keep a constant vigil for hazardous leaks.
One near-term testing ground for the chemical-detecting Motes is
likely to be the new state-of-the-art microfabrication facility
under construction on campus. White, a co-founding director of the
Berkeley Sensor and Actuator Center, hopes to deploy a network of
chemical sensing Motes in the fab. In most industrial chip fabs,
poisonous gases like arsine, phosphine, and silane are detected
with a complicated apparatus that draws air from gas storage areas
past a mechanical roll of chemically-sensitive paper tape that changes
color in the presence of toxins.
White's plan for the chemical-sensing Motes goes far beyond industry
though. Someday, he hopes arsenic-sensing Motes could help rural
villagers in developing nations ensure that their water supply is
safe to drink. On a larger scale, sensor networks could enable much
higher-resolution environmental monitoring at a much lower cost.
For example, he says, much of the water flow and pollution data
from large bodies of water is gathered by ships with on-board sensors.
"A much cheaper and better way would be to drop hundreds of
chemical sensing Smart Dust Motes into the water," White says.
"Then, a plane could fly back overhead and grab all the data."
Richard White's
Home Page
CITRIS
Lab Notes is published online by the Public Affairs Office of the UC Berkeley College of Engineering. The Lab Notes mission is to illuminate groundbreaking
research underway today at the College of Engineering that will dramatically change our lives tomorrow.
Editor, Director of Public Affairs: Teresa Moore
Writer, Researcher: David Pescovitz
Designer: Robyn Altman
Subscribe or send comments to the Engineering Public Affairs Office: lab-notes@coe.berkeley.edu.
© 2002 UC Regents.
Updated 7/25/02.
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