Fully 3D Printed Capacitive Bending Sensor Enabled by 3D Structuring

Advancing 3D printing fabrication methodologies can enable customized wearables and robotic sensing systems with novel sensing architectures, tuned mechanical properties, and higher feature density. In this work, a design and fabrication approach is developed and used to produce a novel soft elastomeric capacitive sensor conceived to measure bending motions. Analytical and finite element modeling are used to create a non-intrusive sensor design that can measure the bending angle of a joint independent of bending direction. Transduction is achieved by 3D printed angular features, with integrated silver plates, fabricated by Direct Ink Writing (DIW) a shear thinning UV-curable silicone ink. The soft sensor achieves a sensitivity of 2.50 +/- 0.04 fF/degrees and detects the bending direction, matching the developed model. This work makes a significant contribution to the fabrication of fully 3D-printed soft electronics, enabling devices with novel architectures and functionalities.