A 1 cm3 ModularAutonomous Sensor NodeforPhysical Activity Monitoring

Traditionally, mostofthesensor interfaces mustbe tailored towards aspecific application. Thisdesign approach is inflexible andrequires several iteration stepsfornewsensor applications. Itusually results inhighcostsforlowand mediumquantity marketproducts. Ontheotherhand,generic interface design reduces thecosts andmayprovide a handy solution formultisensor applications. Thispaperpresents a generic architecture forsensor front-ends. Themodulardesign methodology provides aflexible waytobuild acomplete sensor interface outofconfigurable blocks. Thesettings ofthese blocks canbeoptimized according tothevarying needsofthe application. Furthermore, thesystemcaneasily beexpanded withnewbuilding blocks. Themodularsystemisillustrated in aGeneric Sensor Interface Chip(GSIC) forcapacitive sensors. TheGSICcombines averylowpowerdesign (120gW inON- state) witha smartoptimization oftheoperation cycle. This results inan averaged powerconsumption of48gW ina physical activity monitoring system. Hence,theGSICisa significant steptowards lowcostautonomous sensor nodesfor thesmartenvironment.