A self-powered system for large-scale strain sensing by combining CMOS ICs with large-area electronics

We present a 2nd-generation system for high-resolution structural-health monitoring of bridges and buildings. The system combines large-area electronics (LAE) and CMOS ICs via scalable interfaces based on inductive and capacitive coupling. This enables architectures where the functional strengths of both technologies can be leveraged to enable large-scale strain sensing scalable to cm resolution yet over large-area sheets. The system consists of three subsystems: (1) a power-management subsystem, where LAE is leveraged for solar-power harvesting, and CMOS is leveraged for power conversion and regulation; (2) a sensing subsystem, where LAE is leveraged for dense strain sensing, and CMOS is leveraged for multi-sensor acquisition; and (3) a communication subsystem, where LAE is leveraged for long-range interconnects, and CMOS is leveraged for low-power transceivers. The power-management subsystem achieves 30% efficiency for DC-AC power inversion and inductive power delivery to the CMOS IC and 80.5% overall efficiency for generating three voltages via DC-DC converters. The sensing subsystem has a readout noise level of 23 μStrain_RMS (141 μStrain_RMS including sensor noise), at an energy/meas. of 148 nJ and 286 nJ for readout and sensor-accessing control, respectively. The communication subsystem achieves an energy/bit of 14.6 pJ/4.3 pJ (Tx/Rx) at a distance of 7.5 m and a data rate of 2 Mb/s.