Scientists say a technological revolution is on the horizon BY ROBERT S. BOYD Knight Ridder News Service WASHINGTON -- Tiny machines no bigger than a fingernail, a grain of rice or a red blood cell have been twirling, buzzing and slithering across the pages of science fiction and research laboratory benches for years. Now these Lilliputian gadgets are beginning to enter the real world. Following on the success of crash sensors in automobile airbags, new micromachines are being developed to sniff anthrax or nerve gas, to protect nuclear weapons and to resuscitate laboratory mice. Enthusiasts say they are the advance wave of a technological revolution comparable to the introduction of computer microchips. ``Imagine a machine so small that it is imperceptible to the human eye,'' said Al Romig, director of the Microsystems Science, Technology and Components Center at Sandia National Laboratory in Albuquerque, New Mexico. ``Welcome to the microdomain -- a place where gravity and inertia are no longer important, but the effects of atomic forces dominate,'' Romig wrote in a description of his lab's work published on the Internet. Sandia, along with other government and private research centers, designs ``microelectronic mechanical systems'' (MEMS) -- or ``micromachines'' for short. As their name implies, these miniscule contraptions combine both electronic and mechanical functions in a single device. They are etched out of silicon, the raw material of computer chips, which can be engineered at scales of millionths or billionths of an inch. But unlike a computer chip, MEMS don't just ``sit there and think,'' said Karen Marcus, director of the MCNC Technology Applications Center in Research Triangle Park, North Carolina. Instead, she said a typical micromachine senses its environment, figures out what it means, and then does something useful, such as inflating an airbag, steering a ballistic missile or reporting the presence of poison gas. Although they are difficult to design, diminutive machines made of silicon can be mass-produced cheaply, said Mark Bird, chairman of a new electronics industry committee established this month to develop standards for this dawning technology. They also, he said, work faster, more precisely and more reliably than larger mechanisms constructed of metal. ``Metal gets fatigued and has to be replaced,'' said Bird, an engineer at Amkor Electronics, a semiconductor company in Chandler, Ariz. ``A silicon device will continue to work for decades without wearing out.'' A microsensor used to detect hydrogen leaks aboard NASA spacecraft costs 10 times less, works 10 times faster and is 10 times more sensitive than conventional devices, according to Paul McWhorter, a Sandia engineer. The first widespread commercial application of micromachines are the crash sensors used since the early 1990s in automobile airbags. About a tenth of an inch across, these accelerometers sense a sudden change in a car's velocity, analyze it and flash a signal to inflate the bag in a fraction of a second. Coming next are more advanced mini-detectors that can respond to skids and roll-overs, said Pontus Soderstrom, manager of advanced systems technology for Autoliv (cq), a sensor company in Auburn Hills, Mich. Similar motion detectors are being developed for use in computer mice and in game controllers. ``No more joystick wrist for Nintendo players,'' said Marcus. The Air Force wants to apply similar technology to its missiles, she added. Some other examples of micromachines now on the drawing boards or in testing: --Perhaps the most complex MEMS so far is ``Stronglink,'' a miniature padlock for nuclear weapons designed by Steven Rodgers, a Sandia engineer. To unlock it, an operator enters a 24-digit code that steers a pin through a maze, turns a set of silicon gears with teeth the size of blood cells, pops up a mirror that relays an optical signal to an electronic switch that -- finally -- arms the bomb. One false move by a terrorist would jam the works of this midget Rube Goldberg device forever. --The Defense Advanced Research Projects Agency is developing a chemical and biological weapons detection system called ``Dognose,'' an array of delicate sensors on a silicon chip. ``They're trying to replicate a dog's nose, one of the most sensitive sensors in the world,'' Marcus explained. Hundreds of them could be thrown out the back of an airplane, she said. If they sniff anthrax or nerve gas, they would radio a warning to a computer. Sandia is also experimenting with very small seismographs to detect weapons explosions. ``We could sprinkle them all over the world,'' said Harry Weaver, a technology manager in the microelectronics lab. --Engineers at the Massachusetts Institute of Technology in Cambridge are building gas turbines the size of a shirt button, like miniature jet engines, that weigh less than half an ounce and generate 10 to 20 watts of electricity. They could replace the unreliable batteries now used in laptop computers and other products. MIT is also designing a ``mouse respirator,'' a tiny version of an iron lung for laboratory mice suffering breathing difficulties. These strains of mice take years to develop and cost as much as $200 each, according to Dr. Chi-Sang Poon, of the Harvard-MIT Division of Health Sciences and Technology. ``Until now there was nothing available to resuscitate these mice, which represent a major commitment of research time and money,'' he said. -- Henry Guckel, a professor of electrical engineer at the University of Wisconsin, Madison, developed a microscopic pressure gauge that can be mounted on the tip of a catheter and inserted into the heart to measure its pressure. The device is already in use in Sweden, Guckel said. Another Guckel invention -- a set of gears with teeth measuring eight thousandths of an inch -- is being used in miniature pumps manufactured by a company in Biel, Switzerland. -- Eun Sok Kim, an electrical engineer at the University of Hawaii, is developing midget microphones and speakers, less than a thousandth of an inch wide, that generate extremely fine sound waves. Kim said there is ``good potential for commercialization'' of his devices in ink-jet printers, hearing aids and other products. -- On a slightly larger scale are shrunken versions of Sojourner, the 23-pound, two foot-long rover that cruised the surface of Mars during last year's Pathfinder mission. NASA is building a one-pound, five-inch mini-rover to ride a Japanese spacecraft to the asteroid Nereus in 2001. Its mission is to land on the asteroid, collect samples and return them to Earth by 2006. ``They're running around the lab right now,'' said systems engineer Stacy Weinstein. Further ahead, NASA is considering a fleet of one-ounce, one-inch ``gnat rovers'' proposed by Anita Flynn, a robotics expert from MIT. A host of such little rovers could scatter over the Martian surface, seeking evidence of water. Other applications include switches for high-speed fiber optic lines, radio frequency tuners for wireless communications devices and tiny pumps for ink-jet printers or blood monitors. Despite the fascination with micromachines, Sandia's Weaver cautioned that this is ``not a mature technology. Very few of these things are on the market.'' Several small companies trying to make a living off MEMS have gone bankrupt. ``We're just turning the corner,'' said Marcus. ``The financial community is starting to warm up to MEMS. We're limited only by the imagination of the engineers.''
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