Wireless Hybrid Self-Powered Sensor Using PVDF-Ecoflex Composite for Enhanced Energy Harvesting

The rapid growth of the Internet of Things (IoT) has increased the demand for wearable human-machine interaction (HMI) devices, where sensors play a crucial role in detecting physical inputs and converting them into electrical signals. However, conventional sensors are rigid, bulky, and power-dependent, limiting their application on soft and irregular surfaces like human skin. Here, we propose a piezoelectric/triboelectric hybrid generator (PT-HG) using a composite film to achieve simultaneous piezoelectric and triboelectric charge generation. This sensor produces a higher voltage ($\sim 2.0 \mathrm{~V}$) than a PVDF-only film ($\sim 1.0 \mathrm{~V}$) under a 10 N force and is integrated into a wireless power transfer (WPT) system using capacitive coupling, achieving a 30 cm wireless transmission distance with a received voltage of 0.04 V. A proof-of-concept application is demonstrated in a wireless human-machine interface for smart rehabilitation, where the sensor functions as a self-powered switch in an interactive game. The results highlight the potential of the proposed PT-HG for self-powered wearable electronics, wireless HMI systems, and assistive technologies.