A self-powered smart safety belt enabled by triboelectric nanogenerators for driving status monitoring

Driving status monitoring is highly desirable to ensure safety and prevent traffic accidents. Unsafe and inappropriate driving behaviors can be identified through the monitoring of the driver's body motion. A self-powered smart safety belt composed of two types of triboelectric nanogenerators (TENGs) is developed to monitor the forward position and turning actions of the driver. An auxetic Polyurethane (APU)-TENG integrated in the horizontal strip of the safety belt achieves high sensitivity (0.89V/cm(2)) for strain measurements in the large strain domain (40%-100%), enabling the long range monitoring of the forward position of the driver, which correlates to abrupt and aggressive deceleration. Two sensor arrays of arch-shaped TENGs (AS-TENGs) attached to shoulder and waist location of the diagonal strip in the safety belt can measure the turning directions and angles of the driver, respectively. The AS-TENGs are designed through the integration of two TENGs in the top and bottom arch, respectively, to ensure stable and gradually increased contact between the triboelectric layers in both arches, which leads to a high displacement measurement sensitivity of 47.2 V/cm(3) with high linearity. This work demonstrates an effctive approach to integrate self-powered TENGs sensors seamlessly into existing driving environment for driving status monitoring, expanding the applictions of TENGs in wearable electronics.