Researchers at Clarkson University, NY, have developed wireless bridge sensors which work without batteries. Instead, they are powered by the vibrations caused by passing traffic. This is good news for all the people in charge of maintaining bridges, who will no longer to have to replace batteries installed in hard-to-access locations. As said one of the researchers, 'We have completely eliminated the battery from the equation. Hermetically sealed wireless sensors powered by bridge vibration can remain on the bridge without need of maintenance for decades, providing continuous monitoring of such parameters as ice conditions, traffic flows and health status.' Nice job, but read more...
You can see above Clarkson University Assistant Professor Edward Sazonov and graduate students Darrell Curry and Haodong Li checking data from a wireless bridge sensor on the Route 11 bridge in Potsdam, N.Y. (Credit: Clarkson University) Here is a link to a larger version of this picture.
Assistant Professor Edward Sazonov website Sazonov, who is working for several years on energy harvesting as enabling factor for bridge monitoring, has developed the technology with Professor Pragasen Pillay.
So how these researchers are harvesting energy for their sensors? "Energy was harvested by locating an electromagnetic generator on a girder. The harvester responded to one of the natural vibration frequencies of the bridge. Each time a car or a truck passed over the bridge, even in a different lane from the sensor installation, the whole structure vibrated and excited the mover in the generator, producing electrical energy. Harvested electrical energy powered unique wireless sensors that increased energy output of the harvester and consumed only microwatts of power while performing useful tasks."
Sources: Clarkson University news release, via ScienceDaily, October 17, 2007; and various websites
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