Sewn textile strain sensors: impact of contact-regulating stitch parameters on strain sensing performance

Abstract

Sewn textile strain sensors (STSSs) provide a scalable and textile-integrated approach for wearable motion monitoring. In this work, STSSs were fabricated on a rib knitted fabric using silver-plated nylon thread (SPNT) by lockstitch sewing. The stitch distance and sewing layer number were engineered as structural variables to regulate the conductive contact network within the stitched architecture. The results show that decreasing stitch distance and increasing sewing layers promote more stable electromechanical responses. This enhanced stability is characterized by improved linearity and suppressed signal fluctuation under tensile deformation. The optimised STSS with a stitch distance of 1 mm and three sewing layers exhibited good linearity within 0-20% strain and repeatable performance over 1,000 loading-unloading cycles after an initial conditioning stage. In addition, the sensor demonstrated repeatable responses to small-amplitude limb movements. Fabricated using a conventional industrial sewing process on breathable textile substrates, the proposed STSS is readily integrated into garments and shows potential for wearable motion sensing applications.