3D Printed Soft and Flexible Insole With Intrinsic Pressure Sensing Capability

This work presents a soft, flexible, and low-cost capacitive pressure-sensitive insole developed using resource-efficient single-step 3D printing method. Developed using elastomeric materials, the soft and robust sensory insole can bend and twist in extreme angles. The insole is designed to have four sensing zones to capture the pressure information from the entire contact area. The sensors tested under different condition of applied pressure showed reliable response up to 300kPa without saturation. The sensors exhibit a sensitivity of 2.4MPa(-1) for range of 0 - 60kPa and 0.526MPa(-1) for 60kPa and above with average sensitivity of 1.314 MPa-1 in the entire range. The insole was also tested under varying bending and temperature conditions. Considering the excellent response over a wide pressure range, the presented insole could be used for gait analysis or with anthropomorphic robots for critical information about the terrain morphology. To show the functionality of presented insole, we have also developed an app to display the sensory information obtained via custom-made electronics circuit.