Fort Worth Star-Telegram

FORT WORTH, Texas – As Shashank Priya sees it, tilting at windmills is no longer for crazy people, providing they can fit in the palm of your hand.

Priya, an assistant professor of materials science and engineering at the University of Texas at Arlington, has designed a miniature windmill that – with a light breeze – could provide enough energy to power a wireless Internet sensor.

With such a powerful and lightweight power source, the use of Wi-Fi sensors could be expanded to almost anywhere, dramatically increasing the ability to gather data, Priya said. The implications of his research could touch on everything from studying volcanoes to keeping burglars out of homes.

“You could have a security system on your home powered by wind,” Priya said.

The energy source behind Priya’s windmills comes from the growing field of piezoelectricity, which uses certain crystals that generate an electric current when pressure is applied to them. Piezoelectric technology can be found in an array of items, including push-button cigarette lighters, quartz watches and some high-end cameras.

Research in piezoelectric crystals has looked at numerous ways of harnessing the power of various sources of vibrations, including cars, human movement and ocean currents. The technology is similar to electromagnetic induction, used in battery-free flashlights that only need to be briefly shaken to generate enough juice to work.

“Piezo is better because it shrinks the size dramatically,” Priya said.

Priya and his team of graduate students have designed windmills as small as 5 millimeters in diameter that harness the power of thin piezoelectric strips. The work recently earned Priya a profile in the scientific journal Nature and has caught the notice of colleagues in the scientific community and several technology companies.

He’s built prototypes of larger windmills and plans to build the 5-millimeter version in the coming weeks, Priya said.

The most immediate effect of the windmills could be on scientific research, Priya said. For example, geologists measuring seismic activity in Pakistan to try to gain advance warning of an earthquake typically have to use battery-powered sensors to transmit data or connect the sensors to electric cables. Either setup is woefully impractical and hinders research, he said.

“You can’t go to the mountain every six months to change the battery,” Priya said.

One of Priya’s miniature windmills should be able to generate roughly 50 microwatts of power per turn of its blades, he said.

At that rate, a windmill could store enough power for a remote sensor to transmit a signal about every two hours, Priya said.

In January, Priya is holding a conference on piezoelectric energy harvesting at UT-Arlington’s Automation & Robotics Research Institute in Fort Worth. Scheduled presenters include representatives from Bell Helicopter, Lockheed Martin and Halliburton.

Steve Arms, president of MicroStrain, a maker of miniature sensors in Vermont, is also scheduled to make a presentation at the conference. The company is working on several patents involving energy harvesting from piezoelectric materials.

Mike Robinson, MicroStrain’s vice president of sales and marketing, said the demand for wireless sensors is growing as more companies see it as valuable for monitoring crucial data such as environmental conditions or the amount of strain or stress on a structure.

While cables are no longer an issue as sensors have gone wireless, the need for batteries still means regular maintenance is needed. Eliminating that extra work is a major goal for technology firms, and many are looking to piezoelectric materials as the key, he said.

“The whole idea for energy harvesting systems is you can deploy sensors that are maintenance-free,” Robinson said. “Sometimes you want to deploy these sensors for 10 or 20 years, so you basically want to deploy them without worrying about them.”

The field of piezoelectricity has been steadily advancing since the mid-1950s, and in recent years has gained favor for use in cell-phones as a way to sort radio frequencies, according to Dr. Daniel Stutts, associate professor of mechanical engineering at the University of Missouri-Rolla, who has studied piezoelectricity since 1993.

Priya’s incorporation of wind power with the technology is what makes his work so intriguing and could be a smart and practical way of powering Wi-Fi sensors, Stutts said.

“It’s not revolutionary but evolutionary,” Stutts said. “In this instance, you don’t need a lot of power and as long as you can protect these devices from vandals and the elements, it sounds like a real nice solution.”

There are endless possibilities to how the windmills could be used.

One idea Priya hopes to explore involves a windmill atop a house that could connect to sensors on every window and door. The sensors could be programmed to send out a signal when moved, creating a wind-powered home security system.

UT-Arlington plans to take the patents created through Priya’s research and spin off a separate company that will license the technology.

Not surprisingly, among those expressing interest in Priya’s work is a leading cell phone manufacturer, he said.

Another company has inquired about swapping the solar panels currently used to power weather stations for Priya’s windmills, he said. Replacing solar panels, which can be bulky and unreliable as a power source, is an area where Priya thinks his windmills could someday have their biggest effect.

“Solar is a mature technology. Piezoelectric isn’t,” Priya said. “This is a new technology so it will take some time to grow.”

(c) 2005, Fort Worth Star-Telegram.

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