EGaIn-Silicone-based highly stretchable and flexible strain sensor for real-time two joint robotic motion monitoring

We have developed a highly stretchable and flexible strain sensor based on eutectic gallium indium (EGaIn) and EcoFlex through a simple and low-cost fabrication process. The sensor has two different sensing channels in a single device with novel architecture that can allow fast and effective detections simultaneously from the different joint movements. The sensor is tested with several different angles up to 90° (strain: 250 %) using a 3D printed test setup to imitate joint movements, and it shows superior performance with an exceptional signal-to-noise ratio (69 dB), gauge factor (~3), measurement resolution (0.43 %), and response/recovery times (0.4 s/0.2 s), leveraging the high conductivity of EGaIn and excellent deformability of EcoFlex. Furthermore, the sensor successfully demonstrates the motions of a human finger as a practical application. [Display omitted] •Demonstration of EGaIn-Silicone-based highly stretchable and flexible strain sensor without complex methods or lithography.•Outstanding performance of the sensor with measurement resolution (0.43 %), SNR (69 dB), fast response/recovery time (~0.4 s).•Demonstration as wearable sensors and robotic motion monitoring with a human finger (PIP and MCP joints).