Wearable strain sensor integrating mechanoluminescent fiber with a flexible printed circuit

This paper reports an optical strain sensor that integrates a self-powered mechanoluminescent (ML) elastic fiber with a flexible circuit. The inclusion of an alumina nanoparticle as the additive results in seven-fold enhancement of ML intensity while maintaining flexibility of 120% strain. The sensor facilitates the detection of strain and stretching speed. It attains a sensitivity of 0.0022 lx/(1% strain) and a resolution of 0.2% strain, respectively. We have successfully applied it to detect bending motions of the finger, wrist, and elbow. This wearable strain sensor holds promise for diverse applications in wearable technology.