Resonance-Based Sensing on Large Surfaces Using RF Excitation for Human–Machine Interaction

This letter proposes resonance-based sensing on large surfaces using 13.56 MHz RF excitation to enhance human safety in human machine interaction (HMI). In this approach, whole large conducting surface itself functions as a sensor by varying its resonance characteristics in response to object interactions. The sensing system is compact in design and optimized for operation in the industrial, scientific, and medical (ISM) band. The surface is excited using a single conductor powered resonant coil, which provides good passive voltage gain at -16 dBm input power. A secondary resonant coil is employed to amplify voltage variations caused by human touch on the surface. The system delivers a high voltage output signal that can be directly interfaced with a computing platform through an analog to digital converter (ADC), thereby eliminating the need for external amplifiers or analog filters. This technique offers a cost effective, low power, and large area sensing solution for human robot collaboration (HRC). The proposed system can be seamlessly integrated into machines or robotic platforms for sensing applications in HMI.