Small Systems, Big Business
Applications for tiny sensor packages sure to grow as technology develops. 
Dust Networks developed the SmartMesh architecture that features miniature communications nodes to form a self-healing mesh network of sensors that collect and transmit information. Each node is approximately the size of a postage stamp.
The military may be moving toward the massive Global Information Grid, but interest also is growing in networks that feature lilliputian qualities. Research that began in the mid-1990s is starting to bear fruit in the form of networking nodes that are scarcely the size of a postage stamp. Sometimes referred to as “smart dust” or “motes,” these miniature networking nodes can be integrated with a variety of sensors to then pass on the information that is gathered to the people who need it.
Delivering data gathered by sensors to warfighters as well as business personnel has been a challenge, especially when the sensors are dispersed throughout a large area. Traditional wired networks are impractical for on-the-move troops and can require a substantial investment for companies trying to control costs. Both groups of users can benefit from technology that provides a reliable, power-efficient way to monitor activity in an area, collect data about the surroundings then share that information without installing massive amounts of equipment. A number of companies—large and small—are developing the solution, and already it is helping companies conserve energy and is being integrated into products that could support military operations.
Research into the capability began years ago at several universities. One effort to develop smart dust took place at the University of California–Berkeley. Work conducted by Dr. Kristofer Pister, a professor at the university, caught the attention of the Defense Advanced Research Projects Agency, Arlington, Virginia. Pister has since taken a leave of absence from the university to build Dust Networks, Berkeley, California, a firm that opened with funding from In-Q-Tel, the Central Intelligence Agency’s independent nonprofit corporation that invests in cutting-edge technologies. The company launched its first commercial product, SmartMesh, last September.
Robert Conant, vice president and co-founder, Dust Networks, explains that the networking motes measure 1 square inch and consist of a radio and a microprocessor that transmit data. They are integrated into a system that includes a sensor, an antenna and a power supply. As part of a communications network, these wireless nodes receive and transmit the information gathered by the sensors, which could include audio, visual or seismic data.
Although an additional sensor is required to gather information about the surroundings, the motes do “sense” each other. A mesh, self-healing network comprises nodes that can identify a neighboring node and connect to it. If the network configuration changes because one mote is destroyed, runs out of power or succumbs to signal jamming, the nodes adjust and send data to other working motes in the network. “The important part of this is that it’s incredibly reliable because if one node goes down, another picks up the slack,” Conant maintains.
Information is passed from one node to another, each adding the data it has gathered from its area. They feature 902- to 928-megahertz frequency hopping spread spectrum radio communications and can link to each other when placed between 100 and 200 feet apart indoors and up to 500 feet outdoors. Software designed by companies that develop the host equipment analyzes and shares the gathered information with users in an appropriate format.
This miniature infrastructure is considered low-data-rate sensor networking. Conant relates that, while Wi-Fi networks carry high-bandwidth communications such as video streaming, this technology is at the other end of the spectrum passing along little bits of information.
To conserve energy, the motes are programmed to turn on and off in intervals. Typically, they may remain in the off position for nearly 10 seconds then power up for a few milliseconds just to gather data. The length of the intervals is set when the motes are integrated into the host equipment, which also includes the power supply.
The advantage to this technique, Conant notes, is that the devices require relatively little power and can operate for up to five years on one battery. This feature is especially important in locations—including both factories and battlefields—where returning to the sensor package to replace the power supply is difficult or impractical, he adds.
The SmartMesh system has three components. Compact networking software on each network node executes routing, timing, network optimization and management functions. The SmartMesh Manager is a network interface device that enables open network management and quality of service functions. The individual motes are designed to be integrated into a package that includes an antenna, a battery, sensors and actuators created by other companies that specialize in sensor technologies.
Dust Networks has been working with two customers that are integrating the system into their own products. SAIC, San Diego, is evaluating the potential uses of the motes to enable a range of applications for defense, says Tom Sereno, division manager, monitoring systems division, SAIC. The firm is examining ways to incorporate the technology into products that could be used to monitor remote areas to detect intruders, protect infrastructure and secure port areas.
SAIC has met with at least 10 government agencies to determine their requirements for sensor technology, Sereno says. To date, the company has been exploring how to integrate the motes with six types of sensors: passive infrared, magnetic, acoustic, seismic, a miniature camera and global positioning system (GPS). The GPS capability would allow the sensor to determine its own location and relay that information to users, Sereno explains.
Because the networking mote is so small and power-efficient, the overall size of the sensor package can be slighter than traditional sensor devices. SAIC’s research and development team currently has designed a package that includes a sensor and power source that is approximately the size of a tennis ball. The products are at technology readiness level (TRL) 6 and are being demonstrated for customers, Sereno notes.
Specifically, the company’s inventions could assist with border surveillance or monitoring small areas for foot or vehicle traffic. Passive infrared sensors could act as motion detectors, while acoustic sensors could detect sounds made by people; a miniature camera could be triggered to view what other sensors have detected. For example, after a company of soldiers occupied a cave, they could leave behind these small sensors disguised as rocks to detect activity such as an adversary moving into the cave while they are away, Sereno offers. Other applications could include watching for saboteurs of oil infrastructure or detecting radiation in shipping containers, he adds.
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| Honeywell’s XYR 5000 wireless transmitters, which are 3 to 6 inches in size, allow users to share information about gauge pressure, absolute pressure, temperature and ultrasonic noise. They can be used in areas where traditional hard-wired transmitters are too difficult to implement such as in mills and industrial plants. |
Dust Networks also is working with Honeywell International Incorporated, Morristown, New Jersey, which is integrating the miniature communications nodes into technologies that would benefit the commercial sector. The work is being conducted at Honeywell Automation Control Solutions, Minneapolis, and Dan Sheflin, the sector’s chief technology officer, explains that the mesh networks are being used in a pilot program to help grocery stores better manage energy consumption.
Sheflin predicts the market for wireless networks of small sensors will grow substantially in the coming years. The applications could include installing the networks in buildings to reduce energy consumption by sensing when rooms are not occupied so lights can be turned off and heat or air conditioning reduced. The company is working under a contract with the U.S. Department of Energy that could save trillions of BTUs annually.
Other commercial applications could include monitoring infrastructure. For example, at oil refineries today, personnel must travel hundreds of miles to monitor pipelines regularly. Performing this manual task is expensive. Putting a wireless network in place would allow the pipelines to be examined continuously to check pressure, temperature and flow, saving both time and money.
The keys to the popularity of the technology, Sheflin says, are reliability, power management and cost savings. Because they are self-healing, the networks offer users a reliable flow of information. Power efficiency is an important consideration as well because it eliminates the need to constantly change batteries. Finally, customers can save money because the network does not require the installation of wires. It costs between $20 and $30 a foot to lay wiring; a wireless infrastructure costs approximately $3 a foot, Sheflin shares.
Although this type of networking offers many benefits, Sheflin points out that some matters still need to be resolved. “This is not just a sensor-to-sensor issue. If I have that much more data about my situation, how do I use knowledge management tools to manage all that data?” he asks. Both commercial and military users must address this problem, he states.
Honeywell also is working with other firms that have developed tiny networking nodes, including Ember Corporation, Boston. Like Dust Networks, the company began in academia and with the help of the Defense Advanced Research Projects Agency. Robert Poor and Andrew Wheeler, co-founders of the company, created the initial technology while at the Massachusetts Institute of Technology, Cambridge.
Ember Corporation, founded in 2001, offers what the company calls a complete solution that consists of chips embedded with the firm’s patented networking software and low frequency transmitter technology. Ember currently offers the EM2420 and the EM1020 chips. The former provides the essential elements for development of 802.15.4-compliant applications in an integrated package. This radio standard supports low-cost, low-power, interoperable wireless networking applications for monitoring large and small areas. The latter is a low-cost narrowband embedded radio frequency chip for developing applications in the 300-megahertz to 1-gigahertz range. EmberNet is the company’s software product that provides connectivity.
The company also offers three toolkits. The developer kit includes software, hardware and development tools for integrating the firm’s technology into applications that control systems such as heating, cooling and lighting. The evaluation kit allows users to set up live demonstrations of wireless sensor networks. The Ember Studio enables users to see real-time network traffic patterns and gather live data from multiple sensors.
Ember has a number of clients including the military. Company officials cannot disclose the names of these customers; however, some of the technology’s users have been employing the systems for more than two years in very harsh environments, they say.
Development of this microtechnology goes beyond niche companies. Intel Corporation, Santa Clara, California, began working with researchers at the University of California–Berkeley several years ago through the Intel Research Berkeley laboratory. The Intel Mote project is examining how to create a new platform design that would deliver a high level of integration and low-power operation in a small package. Team members are working with the research community to determine new applications for motes and sensor networks and have developed a prototype of the next-generation Intel Mote. Ultimately, the goal is to create a single microchip mote with layered components, including a sensor and radio frequency microelectromechanical systems, nonvolatile storage, digital/analog silicon and a battery.
The research is being conducted with two markets in mind. First, many experts believe the applications for wireless micro-networks are only now beginning to emerge. Second, as Sheflin points out, once all the data is collected, organizations are going to need larger networks and faster processing speeds to sift through and collate the data gathered. This requirement may feed into the company’s primary business, Intel officials note.
Sereno believes the applications for smart dust technology are likely to grow exponentially. He predicts that the nodes will become even smaller and less expensive as sensor and power technologies evolve. “Compared to the current technology, if the size, cost and power come down another order of magnitude, the mote could be the size of an aspirin. Also there will be the ability to mix and match sensor types and connect to the same network. Often, you lay down the topology and stick with it. But in the future, it may be possible to add more types of sensors,” he says.
Although the technology may support urban military operations in the future, Sereno remarks that this application will not occur for several years. “It’s a way down the road. Some of these things could solve problems like looking around corners in an urban environment, but it won’t be soon. The urban environment is a challenge because there are more people and cars, so it’s harder to sense the threats,” he states.
Web Resources
Dust Networks: http://www.dust-inc.com/flash-index.shtml
Honeywell Automation Control Solutions: www.honeywell.com/sites/acs/
Ember Corporation: www.ember.com
Intel Corporation: http://www.intel.com/research/print/motes.htm
