Development of an extremely compact impedance-based wireless sensing device

Abstract

This paper describes the development of the next generation of an extremely compact,wireless impedance sensor node for use in structural health monitoring (SHM) andpiezoelectric active-sensor self-diagnostics. The sensor node uses a recently developed,low-cost integrated circuit that can measure and record the electrical impedance of apiezoelectric transducer. The sensor node also integrates several components, including amicrocontroller for local computing, telemetry for wirelessly transmitting data, multiplexersfor managing up to seven piezoelectric transducers per node, energy harvesting and storagemediums, and a wireless triggering circuit into one package to truly realize acomprehensive, self-contained wireless active-sensor node for various SHM applications. Itis estimated that the developed sensor node requires less than 60 mW of total power formeasurement, computation, and transmission. In addition, the sensor node isequipped with active-sensor self-diagnostic capabilities that can monitor the conditionof piezoelectric transducers used in SHM applications. The performance of thisminiaturized device is compared to our previous results and its broader capabilities aredemonstrated.