A Wetness Detection Technique Towards Scalable, Array-Based, Fully-Textile Sensing

Fully-textile systems capable of sensing multiple health parameters have the potential to enable novel wearables for a more complete picture of health status in humans. Multiple textile based sensing modalities can be incorporated in an array configuration to extract meaningful physiological information. In this paper, we present a wetness sensing technique embedded in textile fabric to detect the presence of fluids on the skin. The sensing is performed on the area between parallel stitched conductive seam-lines. Impedance measurements performed between pairs of conductive yarns in rows or columns are combined to determine wetness level of a selected fabric area. This technique enables an array-based wetness detection scheme to detect both the presence and extent of fluids within the fabric using an “outside-in” approach which also optimizes fluid detection speed. A custom-designed, modular electronic switching system provides array-based impedance analysis capability to scan multiple areas within the fabric. Overall, the techniques presented here provide a new fully-textile sensing approach to expand the sensor toolkit towards achieving multimodal and ubiquitous sensing in wearable form factors.