A Stretchable Capacitive Sensory Skin for Exploring Cluttered Environments

We present a design and fabrication method using low-cost materials for a new tactile sensor that is highly stretchable (up to 60%) and for which the signal is substantially unaffected by stretching, immersion in water, or electromagnetic noise. The sensor can be wrapped around the front, side and back surfaces of fingers and allows them to flex without affecting the signal. The sensor consists of multiple layers of UV laser-patterned metallic capacitive elements and interconnects, encapsulated in a silicone membrane. It survives large impacts and over a thousand stretching cycles without a change in performance. We use low-cost capacitance-to-digital converters for filtering and communication. To meet different requirements for the front and back surfaces of fingers, the sensitivity of taxels can be tuned by varying the dielectric pattern and in CDC firmware. The skin detects contacts as low as 60 Pa and is intended for manipulation in cluttered environments where the back of the hand may accidentally brush objects.