WILLISTON, Vt. -- Steve Arms started by designing sensors that could be arthroscopically implanted to measure strain on knee ligaments. These days, Arms and his company, MicroStrain Inc., are experimenting with wireless sensing technology that could play a bigger role in assessing the condition of bridges after one in Minneapolis collapsed two weeks ago, killing at least nine people.

The wireless, solar-powered sensor system can provide data on strain, seismic activity and vibrations on bridges, eliminating the need to manually replace batteries once the sensors are installed in hard-to-access places.

Already in place on the Corinth Canal Bridge in Greece and an Interstate 95 bridge in New London, Conn., the sensors harvest energy from the sun using 6-by-9-inch photovoltaic panels. The panels are linked to rechargeable batteries and power microelectronic modules that record data from inside watertight enclosures. The data is transmitted to computers via wireless connections.