Wireless Networks Made of 'Smart Dust'

Sept. 23, 2004 -- If you think the Internet is everywhere now, you ain't seen nothing yet.

The ubiquitous global network may already have interconnected millions of computers to share a flood of digital data. But soon, even more objects — ranging from thermostats to lighting fixtures to maybe even patches of sidewalks and roadways — will be hopping on the network bandwagon.

At least that's the potential put forth by Dust Networks, a start-up company in Berkeley, Calif., and its wireless SmartMesh networking system.

So-called mesh networks function much like the broader Internet. Each device on the network communicates with others in order to pass data from one point, or node, to another. But Dust's SmartMesh does it on a very tiny scale.

Kris Pister, one of the company's founders, developed the technology during his research at the University of California in Berkeley for the military's Defense Advanced Research Projects Agency. The idea, he says, was to develop a wireless system that would allow sensors to communicate with each other and connect to larger networks. And ideally, each node on the network would be tiny, much like a mote of dust — hence Pister's development of "smart dust."

Each "mote" in the SmartMesh system is really a silicon chip. Roughly the size of a quarter, the chip contains the circuitry for a tiny radio transmitter and receiver, as well as proprietary software.

Despite the name, each mote is hardly the size of a speck of dust. To accommodate an antenna, batteries and other needed parts, SmartMesh nodes are roughly the size of a deck of cards.

Created by Pister and his team of researchers over the last 10 years, the software contains the code needed for each smart dust mote to automatically find and connect with each nearby mote. If one mote isn't available to pass along information, the software knows how to instantly reroute the datum to another nearby mote.

More importantly, the special software code also allows each mote to be extremely energy-efficient.

"If you use the radios all the time, you'd require a lot of power," said Pister. Instead, the software coded into the chips turns down the radios almost all the time so they only faintly "listen" for other nearby motes. By tweaking the radio usage, each mote can last up to three years using a single pair of ordinary AA batteries.