Crocheted Capacitive Touch Sensors for Rapid Prototyping of Soft Interfaces

This work presents a novel approach to fabricating soft capacitive tactile sensors using a surface crochet technique to embed conductive thread within crocheted textile substrates. The sensors are mechanically compliant, low-cost, removable, and can be incorporated into a wide range of semi-open-mesh textile substrates, including crocheted, knitted, and loosely woven fabrics. To examine the influence of textile structure and fiber material on sensing performance, we fabricated sensors from acrylic, bamboo, and faux fur yarns, and evaluated their binary touch detection accuracy across four force levels and their signal-to-noise ratio over 30 trials per material. A user study with 15 participants revealed that integrating the sensors significantly affected the perceived tactile qualities of each textile substrate. Finally, we evaluated the sensors in a potential real-world use case: enabling touch-based interactions with a soft, zoomorphic socially assistive robot. Quantitative and qualitative findings highlight trade-offs between sensor performance, perceived tactile qualities, and affective impressions of the robot, informing design considerations for integrating textile-based tactile sensing in soft robotic systems.