Effects of E-Textile Circuit Components on Signal Quality for Wearable Sensing Applications

Wearable sensors are an emerging area of interest for next-generation spacesuits. Wearable sensors can be used to measure things like physiological signals or forces experienced by the body to obtain information about crew members� wellness, mobility, and body position. Obtaining this information within rigid, constrained environments such as spacesuits can be challenging and labor-intensive. Requirements of comfort and conformability are often at odds with both functional and durability requirements involved with wearing a sensing layer underneath a stiff suit. Using E-textile components such as conductive threads and rubbers instead of typical electrical components can help manage the comfort/durability requirements of a sensing baselayer for space suit applications. However, flexible e-textile components may influence circuit integrity and sensor signal quality, and lead to inaccurate measurement. This study seeks to quantify the effects of various approaches to integrating soft textile-based electrical connections (such as threads and rubbers) on the responses of soft strain sensors. Changes in Signal to Noise Ratio (SNR) for textile-based piezoresistive and capacitive strain sensors were measured under wearability conditions including three e-textile lead configurations, a body curvature condition, and a skin proximity condition. Effects were most significant for the capacitive sensor. All lead types maintained strong SNR for the piezoresistive sensor, and body curvature did not induce significant changes. Skin proximity (and particularly motion artifacts) affected the capacitive sensor response, but effects were smallest when using conductive rubber leads.