Self-Elevated 3D Helical Oscillator with Addressable Eigenfrequency for Wearable Interface

Equipped with 3D architecture, flexible electronic devices enable intuitive tactile sensing with enhanced spatial efficiency and skin conformity. However, realizing 3D metasurfaces on a flexible substrate remains laborious. Furthermore, conventional methodology often requires complex electrical connections and communication channels to realize tactile addressing. Leveraging magnetic repulsion among ferromagnetic microstructures, here, the spontaneous formation of a 3D self-elevated helical oscillating unit (SEHOU) on flexible films is presented. Through specific pattern design, the 3D morphology can be precisely tuned upon built-in magnetic moments that balance with the inherent elastic strength. Based on electromagnetic induction, axial vibrations of SEHOU generate sinusoidal electric signals with an intrinsic oscillating frequency. Along with the theoretical model, non-overlapping eigenfrequencies are customized, allowing convenient mapping of mechanical inputs from the received electrical signals. It is shown that crosstalk-free interactions can be achieved on a single piece of SEHOU-based interface, e.g., multi-touch recognition, without compromising the overall wearability. Further, the developed fabric coils and signal analysis modules showcase the potential for wireless Internet of Things. This methodology provides a valuable reference to establish reliable, scalable, and distributed tactile addressing for high-capacity human-machine interactions.