Design of parallel coil arrays with identifiable eigenfrequency elements for wearable human-machine interactions

Wearable electronic devices are considered as a promising platform for efficient human-machine interactions (HMI) in the advancing era of the Internet of Things (IoT). However, the limited capacity often necessitates the arraying of individual devices, which inevitably increase the number of connecting wires, communication channels, and physical chaos. Herein, we propose a high-capacity HMI interface which is composed of parallel-arranged flexible coils, a magnetized composite and a pair of electrodes for electrical connection. When the coils were deformed, the inherent oscillation occurs spontaneously once the mechanical constraint was released. Upon this, the magnetic flux variation caused by the oscillation results in induced current within the coil as defined by the law of electromagnetic induction. Assisted by theoretical model of cantilever beams, eigenfrequency could be effectively regulated and the integration of distinct coils permits a single device to transmit multiple commands and information. Taking advantage of the design, spatial position sensing, virtual piano playing and robotic control have been demonstrated as practical applications, which are mainly based on one communication channel and a pair of electrodes. We expect that the eigenfrequency-dependent mechanism can provide an inspiring solution for the design of high-capacity, effective, and comfortable HMI interfaces in the future.