Sun, Aug 01, 2004 page12

• Computers that talk to each other on the horizon

  We don't have the technology yet, but the day when computer networks and other machines are self-sufficient is not far off

  • NY TIMES NEWS SERVICE
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  For years it was mostly the stuff of science fiction. But now communications technology has advanced to the point where sensors, machines and computers are beginning to talk to each other wirelessly in ways that could dwarf traffic among familiar devices like cell phones.

  Wireless networks of sensors and machinery have long been used in a handful of critical tasks like air traffic control. Now technology is expanding their reach into areas like managing lighting systems and detecting construction defects. But that is just the beginning. As an example, a wireless communications system is being tested to tell precisely when to irrigate and harvest grapes to produce premium wine. Other systems under development monitor stresses on aging bridges to help states decide maintenance priorities, and still others warn when oil tanker equipment is in danger of failing.

  "The range of potential market applications is a function of how many beers you've had," said Tom Reidel, co-founder and senior vice president for business development at Millennial Net, a startup in Cambridge, Massachusetts.

  Hans Mulder, associate director for research at Intel, which has invested heavily in developing microchips for wireless communications, says wireless chatter among sensors and machines "will be pervasive in 20 years."

  Futuristic though it may seem, the movement has captured the interest of venture capitalists, whose investments are supporting startup sensor networking companies like Millennial Net, Crossbow Technology and Ember.

  And for every company already involved, several others are sizing up their opportunities.

  "As a revolution it's not here yet, but as an idea it's everywhere," said Robert Birdsey, a market development manager for Dresser Instruments, a subsidiary of Dresser in Stratford, Connecticut, that makes a range of pressure and temperature gauges. Birdsey made his comment during a break at a recent trade show in Detroit, where he was researching whether Dresser needs to add wireless communications capabilities to its products.

  The grandest visions include concepts that still sound far-fetched, like "smart dust" -- a term used to describe communicating sensors no bigger than grains of sand that might be strewn by the thousands across fields and forests.

  Smart-dust proponents envision such sensors being used to monitor forests for fire, warn soldiers of dangerous substances on the battlefield and alert border guards to activity in remote areas.

  No one has yet come close to making components small enough for smart-dust systems. But a concept known as mesh networking has reduced the power requirements, at least theoretically, to the point where researchers expect to produce, within the next few years, networks of sensor nodes the size of postage stamps powered by coin-size lithium batteries.

  In such networks, sensors would need only enough power to communicate with their neighbors. Messages would be passed along to a more powerful control station or central computer.

  All this has whetted the interest of investors looking for the next big thing in technology. A market research firm in San Diego, ON World, estimated that wireless sensor networks generated less than US$150 million in sales last year but will top US$7 billion by 2010.

  Wireless sensor networks can be deployed in hours in places where it could take months to set up wired networks. Analysts estimate that wiring accounts for 80 percent of the cost of many sensor networks. And wireless networks, unlike wired systems, can be easily rearranged: Moving a node can be as simple as pulling it off a Velcro mount and sticking it somewhere else. Each point or node on the wireless network needs components like radio chips and an antenna, as well as a battery or some other power source.

  But individual nodes, already sometimes as small as a deck of cards, are steadily shrinking as more functions are integrated into their digital cores. The nodes broadcast data to a central computer for processing, either directly or, in large networks, through intermediate traffic management devices called gateways.

  Wireless networks could keep a close eye on situations that are impractical to monitor now because of the high cost of human inspectors or wired systems.

  As the industry looks forward, "reliability, power and cost are the big issues," said Kristofer Pister, the chief technology officer at Dust Networks in Berkeley, California. Pister, who coined the term "smart dust" as a researcher at the University of California, Berkeley, said one unfortunate consequence of the catchy phrase had been too much focus on efforts to shrink the nodes.

  Indeed, powering the sensor networks remains a far more pressing challenge in many potential applications. Power can be conserved by leaving sensors in sleep mode most of the time; internal timers or network signals activate them only when they are needed to take a measurement or pass on a signal.
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