Body-Coupled Multifunctional Human-Machine Interfaces with Double Spiral Electrode Structure

Human-machine interfaces (HMIs) serve as essential channels for communication between humans and machines. However, current HMIs often require the integration of batteries, multiple sensing components, and electrodes, resulting in complex configurations, limited flexibility, and poor scalability. In this work, a body-coupled sensing mechanism employing the power–frequency electric and magnetic field as an energy source is proposed, and an HMI with a double spiral electrode structure (DS-HMI) has been designed based on this mechanism. By comparing the output peaks of the two spiral electrodes and encoding the binary codes “0” and “1”, the DS-HMI detects multiple directions without the need for batteries or complex algorithms. The device demonstrates an ultralow detection threshold (< 0.02 N), exceptional durability (> 100 000 cycles), robustness, high scalability, and rapid encoding capabilities (single-bit encoding completed in 8 ms). The DS-HMI has been successfully implemented in security code systems, UAV control interfaces, and robotic leg control interfaces. This work offers novel insights and principles for advancing next-generation interactive electronic devices, with broad applications in IoT, smart homes, and VR/AR technologies.