Wearable bead-based triboelectric nanogenerator with dual-mode operation for monitoring abnormal behavior in demetia patients

Abstract

A bead-based TENG (BB-TENG) that operates in dual-mode, contact-separation (CS) and free-standing (FS), is demonstrated as a two-in-one device. It serves both as an energy harvester and a sensor. This BB-TENG was designed to collect kinetic energy from two prevalent human movements: pressing related to the CS mode and walking linked to the FS mode. This functionality enables it to detect two typical behaviors of dementia patients while simultaneously harvesting energy: accidental falls corresponding to pressure and aimless wandering associated with walking, thereby enhancing its potential applications. The output characteristics from the BB-TENG was evaluated in terms of open-circuit voltage, short-circuit current and total transferred charge. The flexibility of the BB-TENG, which can be easily attached to a part of the body, gives it superior adaptability compared to other conventional TENGs. Furthermore, its sealed structure provides improved robustness against environmental factors such as humidity, making it suitable for outdoor use. A two-in-one module to enclose a wearable sensor and a flexible energy harvester can immediately alert the caregivers when a dementia patient wanders aimlessly and falls accidentally.