Researchers at Clarkson University in Potsdam, NY have developed technology that converts the vibrations generated by passing traffic into electricity. This electricity can be used to charge small, battery- powered wireless sensors that monitor the structural integrity of bridges.

According to Assistant Professor Edward S. Sazonov, who developed the technology together with Professor Pragasen Pillay, placing wireless sensors on a bridge to monitor its condition and report any changes that could indicate potential failure is easy. The hard part, until now, has been powering them. Periodically replacing millions of batteries, some of which might be located in hard-to-reach places, presented a very expensive logistical problem. Eliminating those batteries, however, would require an alternate source of power.

So how does the system work? Energy generated in the vibrations caused by vehicles passing over a bridge is harvested by a small electromagnetic generator installed on one of the bridgeís girders. Each time a car or truck passes over the bridge, regardless of what lane it's in, it causes a vibration in the structure that excites a mover in the generator, producing electrical energy. This electrical energy can be used to power the sensors. According to Sazonov, "Hermetically sealed wireless sensors powered by bridge vibration can remain on a bridge without need of maintenance for decades, providing continuous monitoring of such parameters as ice conditions, traffic flows, and health status."

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