Smart Textiles: Fundamentals, Design, and Interaction Edited by Stefan Schneegass, Oliver Amft

Contents

Chapter 1
Introduction to Smart Textiles
Stefan Schneegass and Oliver Amft

Abstract This chapter introduces fundamental concepts related to wearable computing, smart textiles, and context awareness. The history of wearable computing is summarized to illustrate the current state of smart textile and garment research. Subsequently, the process to build smart textiles from fabric production, sensor and actuator integration, contacting and integration, as well as communication, is summarized with notes and links to relevant chapters of this book. The options and specific needs for evaluating smart textiles are described. The chapter concludes by highlighting current and future research and development challenges for smart textiles.

1.1 Introduction
Over the last two decades research around textile electronics evolved from initial research explorations into a industrially relevant area. Starting from pioneering investigations on howto integrate conductive lines and circuits into textilesmade during the late 1990s, successive steps led to denser integration, additions of sensors, actuators, user interfaces, and complex textile circuits.While there have been many applications of textile electronics, including industrial filtration, a central aim has always been to realize clothing that could provide additional functionality due to active components and would eventually include a complete wearable computer. Hence, the term smart garments was created. Over the past years, smart textile patches and full smart garments have spun new application fields as well as shaping existing applications centered around sensor-based monitoring and interaction.

Sensor-based monitoring applications include acquiring vital signs in medical surveillance, estimating physical activity in sports, and safety systems for soldiers or firefighters. Their unobtrusive character makes smart garments particularly suited for any physiological and physical monitoring task. In contrast to wearable devices that are used as add-ons to the wearer’s gear, clothing, enriched with smart textiles, can provide a convenient integration in everyday life for their wearers. Moreover, smart garments may not change the perception of clothing and thus enables wearers to privately use technology, which is sought in many monitoring applications. Often, it is underestimated, how much body coverage and integration space clothing provides to hostmonitoring functions, ranging from shirts and pants to jackets and underwear, respectively.

An essential feature for any monitoring application is the data quality provided. One long-standing challenge in the field of smart garments is thus how to maximize artifact resistance and measurement robustness, while retaining textile-like mechanical bend and stretchability. A variety of strategies to maximize the signal-to-noise ratio (SNR) are being considered, from mechanically or chemically optimizing electrode contact and conduction, to multimodal sensing and data fusion. However, it is not only the momentary signal quality that matters. Frequently it is the regular usage, handling, and cleaning procedures, which critically affects longer-term reliability. Most of today’s textile handling procedures were established for classic fabric and textiles, thus resulting in quick deterioration of sensors and SNR.Atypical example is washability and, in particular, the laundry cycle count that a smart garment can sustain without deteriorating in function. Another key challenge is scalability of the textile and garment production processes. Over the last century, textile production evolved into low-cost, large-volume processes. The production processes are contradictory to the diversification of smart garment production requirements across applications. Essentially, there is insufficient volume in each smart garment application to warrant investment by textile manufacturers. We continue to discuss the challenges for smart garment monitoring in the chapter contributions detailed further below.

Smart garments shape the way we may interact with computing systems in the future. Current interaction techniques on mobile devices mainly realize explicit input from users via touch and speech to execute certain commands. In contrast, smart garments move interaction from finger tips to a intimate body contact. Combined with the ubiquity of clothing in our everyday life, interaction becomes continuous and potentially involves the whole body. Explicit and implicit interaction techniques allow users to control computing systems while input and output devices in smart textiles remain unobtrusive. A new core element is implicit interaction based on the measurements of subconscious behavior and state such as of a user’s physiological condition, posture, or movement during everyday activities. Implicit interaction in smart textiles may leverage its potential in combination with explicit user input involving full-body and arm gestures.