Smart Dust - Keeping track of the young and the feckless


By Edwin D. Reilly, Jr.

For The Sunday Gazette


          Decades ago, I made one accurate prediction but failed to make another. I told the head librarian at SUNYA (now the University at Albany) that the day would come when there would be no essential difference between the library that she managed and the computing center that I did. I envisioned that this would come about through access to both remotely stored copies of books and to computational power over networked computers—a computer utility so to speak. What I did not foresee, despite my background in physics, was how incredibly small and affordable computers would become. So now we have the best of two worlds, the continued existence of the physical books that provide both tactile and literary pleasure, and, dispersed among them, powerful Internet-ready PCs available to library patrons.

But the incredible shrinking computer will get smaller still, or at least specialized wireless and wearable ones will. There are now such things as sensor networks, distributed computing networks whose nodes are thousands of very small low-power wireless sensors that relay information about their environment to a host computer for processing. The sensors may be placed throughout an extensive area to measure such things as temperature, vibration, or light levels, or to perform more complicated tasks such as taking pictures or analyzing chemicals. The prospect is that these tiny sensors and all their communications gear might some day be squeezed into a package about the size of a grain of sand, one millimeter on a side, that can be produced for a few cents each. This would mean that thousands of them could be scattered from aircraft and allowed to settle like "smart dust" over a field of interest.

Current sensors are not nearly that small and still cost about $200 each, but are nonetheless finding interesting applications. These range from monitoring the growth of redwood groves, marking the locations of land mines, sensing the need to sprinkle lawns or irrigate fields, detecting impending earthquakes, recording wear and tear on bridges and buildings, and gathering information about temperature, humidity and other factors and help firefighters predict and control the spread of wildfires. Oh how badly California needs such help.

           There have been four generations of “smart dust” so far, each smaller than the last. The sensors installed in the redwood grove are the size of a quarter, but the latest ones are no bigger than the head of a nail. And the sensors need not be scattered, they can be carefully placed. So now I'm ready to make some new predictions. Once these sensors get small enough and cheap enough, they could be used to solve two very major societal problems. Note that I said "could," but whether they are ever deployed in the way I envision raises questions of civil liberties. The problems both relate to being able to know where people are, at any moment, no matter where they go. Their solution requires that the sensor not only be small, but also be able to access the Global Positioning System (GPS), the earth-encircling web of satellites that keep drivers and suitably-equipped hikers from getting lost.

    Well, few of us would be willing to "report" our exact whereabouts constantly. No way, Jose. But there are two classes of people who might be deemed either not yet old enough to have unrestricted roaming rights, or who have forfeited that right through commission of a crime. The first such class is that of children. Far too many get lost, wander into unfenced ponds or swimming pools, or, sad to say, are abducted. Just recently, a boy perished in the woods in New England because even a large search party could not find him in time. But lost or abducted children with a microsensor wouldn't stay missing for very long. Had the aptly-named Elizabeth Smart been wearing an unobtrusive "Smart bracelet" that continually broadcast her whereabouts to a central computer, she would have been found in nine minutes rather than nine months. And no longer would frantic parents have to search for a young child left sleeping in a garaged school bus.

  The other class consists of the millions of nonviolent criminals wasting away in prisons that we just can't afford. If each bore a sensor of the kind I've described, then the monitoring computer could ascertain that they haven't traveled any further from home than needed to reach their workplace (or place of community service). This would not only obviate the need for a cruel and expensive cage to keep them in, they would also have to provide for their own sustenance, adding to the savings. When one does deviate from the authorized route, the central computer not only alerts the sheriff that the "prisoner" has fled, but tells exactly where he is now, the direction he's headed, and how fast.

But what's to keep the child abductor or confined felon from throwing away the sensor? For the felons, their ankle bracelets must be so difficult to sever that their monitor would know they've fled, and where they are, before they get very far. For the children, their particle of "smart dust" must be carefully hidden within something they are wearing.

This reminds me of the little girl who asked her mother whether it was true that "thou art dust, and unto dust thou shalt return." Being thus assured, she said "Then look under the bed, Mom; somebody there is either coming or going."


Ed Reilly lives in Niskayuna and is a regular contributor to the Sunday Gazette opinion section.