Plug-n-play e-knit: prototyping large-area e-textiles using machine-knitted magnetically-repositionable sensor networks

TL;DR

This work tackles the challenge of rapid, large-scale prototyping of e-textiles by introducing plug-n-play e-knit, a non-invasive, reconfigurable platform that fuses machine-knitted conductive networks with soft magnet connectors. It enables repositionable sensor modules across a garment via a differential $I^2C$ communication scheme, demonstrated over a $2700~\mathrm{cm}^2$ area, and validated with an IMU-based motion-tracking network. Key contributions include the machine-knitted textile network, the PME-based soft magnet connectors, and modular sensing units that can be inserted and relocated without fabric damage, enabling efficient design iterations for body-motion capture and skin-temperature sensing. The approach has practical impact for ubiquitous smart clothing development by providing scalable, repeatable, on-textile testing and optimization of sensor placement and network topology under real-world wear conditions.

Abstract

Prototyping electronic textile (e-textile) involves embedding electronic components into fabrics to develop smart clothing with specific functionalities. However, this process is still challenging since the complicated wiring setup is required during experimental phases. This paper presents plug-n-play e-knit, a large-scale, repositionable e-textile for providing trial-and-error prototyping platforms across the textile. Plug-n-play e-knit leverages industrial digital knitting machines loaded with conductive thread to automatically embed a communication and power supply network into garments, in addition to using soft magnet connectors to rearrange electronic components while preserving the stretchability of the garment. These combinations enable users to quickly establish e-textile sensor networks, and moreover test the performance and optimal placement of the electric devices on the textile. We demonstrated that our textiles leveraging custom I2C protocols could achieve the motion-resilient motion-tracking sensor network over a 2700 $cm^2$ garment area.

Figures (7)

• Figure 1: Design overview of plug-n-play e-knit comprising the textile garment, sensing module, soft magnet and control hub.
• Figure 2: Fabrication process of the textile including (a) designing the thread pattern and producing with industrial knitting machine (MACH2XS, SHIMA SEIKI MFG., LTD.), (b) covering irrelevant channels' conductive threads with square pieces of paper to ensure insulation and coat corresponding channels with conductive paste to enhance conductivity, (c) aligning the gaps in each channel with the corresponding channels of a vertical conductive strip, (d) affixing the strip using Thermoplastic Polyurethanes (TPU) under a heat press machine at 0.7 and 120.
• Figure 3: (a) A close-up of 5 wide PME's stretchability. (b) Relationship between the tension and the strain of the 5 wide PME. The solid line denotes the mean and the shaded areas depict the maximum deviation of the three PME testing samples.
• Figure 4: System overview of the sensing module.
• Figure 5: (a) The setup of evaluating 9 position's signal attenuation. (b) Comparison of SCL-signals acquired at 9 locations within 0.1. (c) Comparison of the number of 5 intact sensing modules left after different movements.