Self-powered impact sensors based on electrospun acrylonitrile butadiene styrene triboelectric nanogenerators for wearable helmet applications

Abstract

The recent developments in the self-powered sensing technologies have immensely contributed to wearable energy harvesting systems for safety applications. This study presents the first elucidation of incorporating electrospun acrylonitrile butadiene styrene (ABS) nanofiber-based triboelectric nanogenerators (TENGs) into a smart wearable helmet for real-time impact detection and wireless alert transmission. The neat ABS nanofibers produced after the 4 h electrospinning process showed the highest triboelectric output when compared to the 2 h, 6 h, and 8 h electrospun samples with an open circuit voltage (V_oc) of 48.1 V, a short circuit current (I_sc) of 3.1 μA, and a transferred charge of 13.4 nC. The effect of the impact force and contact frequency was systematically studied and the optimal efficiency was confirmed at 5 N and 10 Hz. The 1 cm² TENG device achieved a peak power density of 903 mW m⁻² at a 70 MΩ load resistance and cycling stability over 4000 cycles showed its strong potential for energy harvesting and sensing applications. On simple hand tapping, the device exhibited an output of 200 V and 12 μA, which was used to charge a commercially available capacitor. A smart wearable helmet was designed for real-time impact detection by strategically placing the fabricated TENG units in the helmet at different positions. The signals generated from the helmet were processed using a microcontroller and transmitted through a Bluetooth module ensuring rapid detection and user notification.