Spike-based Self-Calibration for Enhanced Accuracy in Self-powered Pressure Sensing

Self-powered pressure sensors are gaining popularity in human–machine interaction and mobile systems for their energy efficiency. Among the many types of self-powered sensors, triboelectric sensors have numerous advantages, including diversity of materials, ease of fabrication, and high voltage output. However, their signal is prone to be affected by both intrinsic and extrinsic factors including environmental change and discharging, which can significantly deteriorate the accuracy of measurement. To address this, a simple yet effective solution is proposed: a mechanically induced spike-based self-calibration method for a triboelectric pressure sensor. The sensor generates two signals: an open-circuit voltage and a spiking calibration voltage, enabling real-time calculation of current surface charge density. The calibration signal generates a spike at each predetermined discrete pressure change, whether positive or negative direction, denoting the corresponding direction of the pressure variation. This system successfully calibrates signals from various effects, including humidity change (20%–80%), discharging (over 10 days), and charge accumulation. This sensor has potential applications in precision agriculture for efficient crop harvesting and packaging in diverse environmental conditions.