Microtetrahedral Electrode-Enhanced Wearable Capacitive Dual-Mode Sensor for Integrated Tactile Pressure and Proximity Detection.

Advances in artificial intelligence are enabling flexible intelligent sensors with performance rivaling or surpassing human perception. In this work, we have introduced a dual-mode capacitive sensor featuring double-sided microtetrahedral electrodes (DSMEs) for proximity and contact detection. The innovative architecture design effectively minimizes the sensor's viscoelasticity and equivalent modulus, achieving a high pressure sensitivity of 1.29 kPa-1 across a broad linear response range of 0-20 kPa and a detection upper limit of up to 800 kPa. The sensor demonstrates rapid response and recovery times of 125 and 65 ms, respectively, along with stable signal output maintained over 10,000 loading cycles. Moreover, the microtetrahedral structure electrodes produce a nonuniform electric field, which enhances noncontact sensing capabilities through the capacitive fringe effect, allowing the sensor to detect stainless steel plates at distances of up to 100 mm. Leveraging its exceptional dual-mode sensing capabilities, the sensor has demonstrated remarkable performances in human motion monitoring, object shape recognition, and material type perception. With the integration of machine learning, the sensor achieves an impressive material classification accuracy of 98.75%. These results establish a valuable reference for the development of multifunctional intelligent perception systems in the next generation of intelligent robots.