Highly complex yet inexpensive enough to use in large numbers, microsensors could become a cost-effective source of data in almost-unimaginable volume and detail.

In the near future, applications like microsensor networks could report on every machine in a factory, churning out data on product quality and equipment health.

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Mini measurements, major impact

How microsensors will revolutionize the way you see your business

by Robert Ebisch

WHEN VINEYARD WORKERS IN NORTHERN California go out in April to tie the young vines to trellises, they might carry microsensors built into 1 cm2 silicon chips, which they will clip to the leaves of every fourth plant in every other row.

The chips will talk to each other and the vintner's computer using a wired prototype installation. Future installations will enable wireless networking. An initial GPS reading determines the first chip's location. Like dominoes, each subsequent chip tracks its own position based on the last, all measuring and reporting-as often as the vintner desires-light intensity, humidity, temperature and the amount of moisture escaping from the leaf.

Real-time feedback reveals which vines require additional fertilizer and which need more water. A data warehouse supports this analysis based on parameters set up by the vintner. It can reveal, for example, how leaves trimmed in different locations correlate to the amount of sunlight the remaining leaves receive and the quality of the grapes produced by those vines.

Fetzer Valley Oaks in Hopland, Calif., could be one of the first vineyards in the world to use this high-tech system. Fetzer's owners are interested in volunteering a portion of their vineyards to test a prototype of Oakland, Calif.-based Applied Microsensor's MicroWeatherStation.

"In the prototype, we're looking at each component costing us $10 to produce, but that's a first-time production," says Kimberly Cornett, Applied Microsensors' vice president of engineering. "With improvements to the fabrication process and outsourcing, we project 85 cents per component within two years. Over five years, we could get down to 15 cents or a quarter per unit."

The MicroWeatherStation System illustrates the emerging potential of microsensors. Industry insiders expect that the same kind of microfabrication technology that produces computer chips will likely lead to the ability to manufacture microsensors simultaneously by the thousands, even millions. Highly complex yet inexpensive enough to use in large numbers, they could become a cost-effective source of data in almost-unimaginable volume and detail.

"The flood of data points-things that could be read and patterns understood-rises exponentially in this next chapter in the marketplace," says Glen Almendinger, president of Harbor Research, a Boston-based technology consulting and research firm. "The emergence of large volumes of silicon-based micromachines and sensors could add huge complexity to data management and services."

To handle that volume of data, microsensor devices must include computational ability, wireless communication devices and an internal power supply. Such devices have been studied or developed to measure mechanical, magnetic, optical, chemical, thermal, biological and other data. Potential applications include monitoring of manufacturing parts and processes, electric power grids, oil and gas distribution systems, and bridges, as well as other public infrastructures. Microsensors promise to boost the information content of environmental and medical monitoring.

Vibration microsensors and acoustic emissions microsensors are already used to detect signals that precede machine and part failure. Such sensors could also be used to reconstruct equipment failure and, potentially, catastrophic events such as plane crashes or auto accidents. But that's only the beginning of what scientists see as the full potential microsensors.

Other applications currently in development include inserting a chip into every slab of concrete in a highway in order to measure and report surface wear and tear. Sensor-equipped roadway signs can monitor their reflectivity and report when it is time for a replacement. Lawn-care companies can bury sensors in customers' yards to measure soil acidity, moisture and more, allowing this service industry to predict, instead of just react to, lawn conditions. Even humans can benefit from microsenor technology; diabetics could have sensors implanted to continuously monitor their blood sugar and alert emergency medical personnel if levels reach critical highs or lows.

Sensing in the supply chain
Some see microsensors as the next wave of supply chain management technology that will follow radio frequency identification (RFID)-semiconductor chips embedded in products that transmit electronic product codes. Communicating wirelessly with other devices, RFID tags can track products moving through the supply chain. Data captured from bar codes and RFID tags in warehouses and elsewhere reflect "transactions," but microsensors will increasingly capture "interactions," says Teradata CTO Todd Walter. "It's a new level and volume of data that gives you a whole new perspective on what's going on in companies and processes."

This data will become increasingly important to companies, and it will require different kinds of statistical and trending analysis, Walter adds. "Understanding patterns will require a variation at the least and, at the most, a completely new application," he says.

Jerry Hill, Teradata's director of supply chain intelligence, believes that microsensors will eventually generate as much data as RFID tags. "Currently, RFID is two to three years out from a data volume standpoint, but companies such as Wal-Mart will be requiring key suppliers to apply RFID chips-at the minimum-at the pallet level," Hill says. "When it gets to the product level, we'd better be prepared. I'm seeing a similar scenario building with microsensors, just a few years behind RFID."

Boston-based Ember Corporation makes networking radios that connect to sensing devices made by Sensitech for "cold chain management."

The technology, which is currently the size of a business card, rides inside shipments of fish, produce, pharmaceuticals and other products to closely monitor temperature and humidity.

The recipient then downloads the data to find out what the conditions were during shipping. It's just one of countless possible sensor applications destined to shrink in size and price.

"We'll have a product out next year that will be around a $1 price point," says Ember Executive Vice President Adrian Tuck. "At that point, the idea becomes exciting to fit one on each container [shipped]."

Communicating with tags and networks
The distinction between RFID tags and networks of communicating sensors will become increasingly blurred, says John Huggins, executive director of the University of California's Berkeley Sensor & Actuator Center (BSAC).

"Instead of the tag having just the identifying serial number of a unit, it could just as well have a very low-cost, piezoelectric pressure sensor," he notes. "If there was a shock to a pallet during shipping, for example, it could be very valuable in mitigating damage claims … to have a record of whether and when that unit experienced undue stress. A piezoelectric device can be very cheap. If the volume were high enough, you could probably drive applications down into the dimes."

The BSAC, which is also home to the National Science Foundation Industry/ University Cooperative Research Center on Microsensors and Actuators, collaborates with several "industry affiliates" on a variety of real-world microsensor applications.

The center currently works with:
> A water company to measure strain in buried water pipes;
> A bearing manufacturer to measure strain in large industrial machinery;
> The California Energy Commission on its vision of sensors in 10 million homes for geographical targeting of electrical demand on the grid.

BSAC researchers are investigating numerous other potential applications such as the use of vibrational sensors for gas mains to detect shockwaves that precede an earthquake's major dislocational force within seconds to cut off the flow of gas.

"Monitoring a refinery or chemical plant, there are things we'd like to have continuous information on but can't right now because of cost," says Ignatius Chan, a research scientist with ChevronTexaco Corporation, a BSAC industry affiliate. "We'd like to know, for example, when to replace pumps and parts, valves and flanges, and rotary equipment. We have scheduled maintenance programs now, but they're scheduled at a certain interval. We'd like to know continuously how our systems are performing. Since we move so much volume, a small percentage increase in efficiency means a lot of money."

Berkeley's Smart Dust project aims to develop a device the size of a grain of sand and inexpensive enough to use in large quantities. Potential uses range from inventory control to intelligence gathering during military conflicts.

"While microsensors are generally silicon-based, we're also working on polymer-based sensors, and they could be very, very cheap," says Huggins.

In the near future, applications like microsensor networks could report on every machine-even every part of every machine-in a factory, churning out data on product quality and equipment health.

"If you capture that data and keep it over time, you can see how fast tools wear out and predict more accurately when they should be replaced," says Teradata's Todd Walter. "You can see how different tolerances match up, match the data with customer feedback, feed that back to manufacturing and engineering, and really understand the trends."

"The more inexpensive it is to instrument the process," Walter continues, "the more data people will want."

The increase in data coming from networked microsensors promises to be exponential, especially considering the terabytes of data that customer relationship management and enterprise resource management can create alone, according to Ian Barkin, managing director of The Focal Point Group, a research and advisory firm specializing in M2M (machine-to-machine) technologies.

"With every mechanical asset just pumping data, it will be overwhelming unless there are applications that can analyze and report on it," he says. Fortunately, the fully scalable Teradata Warehouse and its suite of products is capable of doing just that. T

Robert Ebisch is a Golden, Colo.-based writer who has written for USA Today, Science News, The Washington Post, Consumers Digest and Wireless Review.

ILLUSTRATIONS BY DAVE CUTLER