Metamaterial-enabled battery-free wireless sensor networks for unencumbered human-machine interactions.

Wireless body sensor networks could enable unencumbered human-machine interfaces for robotics, assistive healthcare, and immersive computing. However, their widespread adoption remains constrained by bulky batteries and inefficient wireless communication. Here, we report a battery-free wireless body sensor network enabled by a dual-mode metamaterial textile for continuous and unobtrusive human-machine interactions. The textile, digitally embroidered with liquid-metal fibers, establishes ultra-wideband electromagnetic pathways to simultaneously support efficient near-field power transfer and Bluetooth communication across the entire human body. This architecture enhances data throughput by 37.8 times and doubles wireless power transfer efficiency compared with emerging near-field clothing. When worn, the metamaterial-integrated clothing allows an NFC-enabled smartphone to serve as a central hub, wirelessly delivering power to and acquiring multimodal signals from distributed battery-free HMI sensors. We demonstrate that this battery-free body sensor network remains robust during motion and enables intuitive, unencumbered interactions in robotic control, virtual reality, and human digital twins.