Active sensing platform for wireless structural health monitoring

Inorder tomonitor structures withahighdegree ofaccuracy, itis Thispaper presents SHiMmer, awireless platform forsensing and often required toinstrument thestructure withahighdensity of actuation that combines localized processing withenergy harvestingsensors. Theinstallation ofa wiredsensor network canbe toprovide long-lived structural health monitoring. Thelife-cycle of prohibitively expensive, sinceitmay require changes tothe thenodeissignificantly extended bytheuseofsuper-capacitors for structure itself (e.g. drilling holes inwalls) andtakeseveral months energy storage instead ofbatteries. During this period thenodeis inbigbuildings andinfrastructures. Bycontrast, wireless sensor expected toworkcompletely maintenance-free. Thenodeiscapable networks provide structural engineers withacheapandeffective ofharvesting upto780Jperday.Thismakesitcompletely self- waytoinstrument astructure andcollect dataregarding it,by sufficient whileemployed inrealstructural health monitoringeliminating theneedtocable thestructure under test. applications. Unlike other sensor networks that periodically monitor Wireless sensor networks, however, also create complexities oftheir a structure androute information toabasestation, ourdevice own.Inparticular, sensor nodeshavesevere energy constraints. acquires thedata andprocesses itlocally after being radio-triggered Battery-powered sensor nodes needperiodical humanintervention, byanexternal agent. Thelocalized processing allows ustoavoid inorder torecharge orreplace batteries. Thelife-cycle ofbatteries is issues duetonetwork congestion. Ourexperiments showthat its 32- onlyafewyears. Somesolutions allow thelife-cycle tobeextended bits computational core canrunatIOOMIPS for15minutes daily. [7] [30], butafter 10years their capacity isreduced by50%[28]. Thiswouldresult inconsiderably highmaintenance costs. A typical