Albert Heuberger, Fraunhofer-Institut für Integrierte Schaltungen
Christine Kallmayer, Fraunhofer-Institut für Zuverlässigkeit und Mikrointegration
Thomas Norgall, Fraunhofer-Institut für Integrierte Schaltungen
Peter Schneider, Fraunhofer-Institut für Integrierte Schaltungen
Christian Weigand, Fraunhofer-Institut für Integrierte Schaltungen

Being discussed for years in the context of next generation personal computing, wearable technology is currently among the most prevailing topics, latest since the U.S. CES trade fair in January 2014. A lot of related products shaped as smart watches, wristbands, clips or even necklaces have been announced or reached the market. However, the consumer market is still dominated by the endless variety of apps that benefit from the dramatically increasing capabilities of permanently evolving smartphones. Mainly addressing younger consumers and their lifestyle demands in the past, now an increasing number of apps are dedicated to senior users and health- and safety-related use cases. As an example, app112 is an innovative emergency app with a number of functions for initiating distress calls by automatically dialing the international emergency number 112. An alarm can be raised utilizing on-board sensors of most current smartphones, including a function for fall detection – essential for senior users. For sophisticated motion sensing and fall detection algorithms see e.g. ActiSENS by Fraunhofer IIS.

Dedicated Wearable Devices

According to an Internet-based survey of thousands of Americans (who have Internet access) by Endeavour Partners in September 2013, one in ten U.S. consumers aged 18+ now owns a modern activity tracker . The study reveals that more than half of the owners do not use it anymore. “A third of U.S. consumers who have owned one stopped using the device within six months of receiving it. The lack of long-term utilization raises the stakes for any company incorporating wearables and related data into its products or services.”

To avoid this dilemma, moving towards “serious” applications and customers, particularly delivering health status and context information, is an option. Two related examples feature embedding of wearables in a semi-professional infrastructure of dedicated other components and completely novel consumer products that integrate lifestyle and health-related functions similar – however not yet equivalent – to professional medical devices:

CarePredict™ is a multi-component system that monitors seniors in their homes to recognize declines in health status before an emergency occurs. A wrist-worn sensor detects motion type – walking, running, sitting, standing, or lying down, speed, number of steps, their duration and frequency and provides localization information. Data transmission and battery charging are performed wirelessly. Small batteryoperated beacon components provide indoor localization and send the sensor information to be analyzed to a hub that builds a user-friendly data repository, the “Rhythm Journal”. Via Internet, the hub can send data to be analyzed to a cloud where proprietary servers can access it. The system learns normal user activity patterns over the first seven days of use. Measured daily activities are documented in the Rhythm Journal where caregivers and family members can view and compare them over weeks and months.

Some novel products explicitly feature functions traditionally performed by medical devices. The Cosinuss Earconnect C-SP 01 is a mobile in-ear pulse and heart rate monitor that transmits measured data to a dedicated pulse computer or a smartphone using Bluetooth 4.0 or ANT+. The waterproof Bragi Dash goes some steps further and combines pulse oximeter-based heart rate and oxygen saturation calculation, body temperature measurement, accelerometer-driven performance tracking and wireless in-ear headphone and headset functionality with a 4GB MP3 Player. It uses Bluetooth 4.0 technology and a CSR aptX® audio codec for mp3 and AAC audio reproduction, noise is reduced based on built-in microphones. The user interface is a trackpad-like touch sensitive surface. Announced for fall 2014, it is developed by the Munich-based startup Bragi, which could raise a +3 Mio. € crowdfunding budget.

Success Criteria for Wearables – Chances and Challenges of Textile Integration

As a general approach, the study mentioned above lists a set of well-known criteria that are essential for adoption and short-term utilization of wearable products and services. It complemented these aspects by less known behavioral science factors for long-term engagement. These criteria include clear and relevant user benefit, design and form factor, quality and robustness, intuitive, familiar and seamless user experience. Furthermore, they comprise lifestyle compatibility with minimized need for behavior change, integrability by open APIs and data interfaces and – last not least – the overall product utility that must go much beyond the mere collection of data. Most relevant behavioral factors are habit formation, social motivation and goal reinforcement. Similar criteria and requirements are not only defined in numerous other recent publications on this topic, but also direct the development of wearable technologies in the industry and in R&D organizations.

For optimal wearable package solutions aiming at serious and professional use cases, smart textiles provide indispensable contributions – particularly when users with functional limitations are addressed. Ongoing miniaturization of electronic components is an enabling and driving factor for textile integration of smart functions and user interfaces. Integrated electronic components can enhance textiles with new capabilities such as sensing and lighting. However, there are still substantial problems to solve, e.g. in the areas of electrical and mechanical contacts between electronics and textiles, availability of manufacturing technologies and materials for textile use, long-term reliability and safety during use, washability, specific approaches for data communication and the lack of standards. Starting from currently available technologies, various cases can be successfully addressed by smart textile solutions.

A Family of “Textile & App” Solutions

The Fraunhofer IIS VitalShirt concept provides building blocks for solutions combining smart shirts and apps. The Sport and Training VitalShirt supports athletes to maintain recommended training intensity and frequency for optimal training effect. The Stress VitalShirt informs managers, rescue workers or pilots on current stress level and ways to relaxation. The Health VitalShirt monitors cardiovascular condition and general fitness and derives recommendation for dosed exercising. The Sleeping VitalShirt realizes sleep lab functions, providing statistics on sleep quality and apnea events with optional threshold-based real-time alerts. A smart baby romper monitors vital functions and helps to prevent sudden infant death. A number of demonstrators (see Figure 1) feature VitalShirt building blocks, e.g. the FitnessSHIRT for mobile continuous acquisition of physiological data; textile electrodes pick up the electrical cardiac activity. A stretchable band around the thorax measures chest movement providing information about respiratory performance and effort. Heart rate (pulse), heart rate variability (HRV), respiratory rate, inspiration and expiration times are derived from these data. Power supply and electronics for local storage and wireless transmission of data are housed in a small box attached with snap fasteners and are removable for washing. Sampling rate, battery capacity and wireless technology can be adapted to application and client requirements. Use cases include cardiovascular care, monitoring emergency responders in dangerous environments, support of exercise monitoring, biofeedback for therapy and stress management as well as sports and leisure.

Figure 1. VitalShirt / FitnessSHIRT demonstrators (Fraunhofer IIS / Fraunhofer IZM)

Figure 1. VitalShirt / FitnessSHIRT demonstrators (Fraunhofer IIS / Fraunhofer IZM)

Going beyond smart shirts and apps, Fitness Coach and Fitness Assistant are tracksuit-based demonstrators designed to maintain and retain physical mobility by professionally supervised and personalized health and fitness training program. An intelligent sensor suit collects body movement data, a t-shirt provides respiration sensing (see last paragraph). A tablet serves as user interface, analyzes the collected data, enables user feedback and instructs on fitness or rehabilitation exercises (see Figure 2 top left). The system can be used at home to motivate regular exercise. Applications particularly include physical rehabilitation and prophylactic workout programs for seniors. For young users the motion-sensing suit could also be combined with games or virtual competitions. The sensor suit technology is based on tri-axial accelerometers, which allow for future reducing the size of the sensor components. Figure 2 (right and bottom) illustrates the urgent need for textile embedding of the numerous leads and sensor components. One on-body central unit is attached to each jacket and pants. Slightly larger than a business card case, these units pull collected data and transmit them to the tablet. The Fitness Coach and Fitness Assistant can be easily integrated into telehealth infrastructures, connecting to a human coach from a telehealth service provider. Thus, personalized exercises can be guided via tablet or smartphone, including direct compliance monitoring by professionals.


Figure 2. Fitness Coach / Fitness Assistant: Audiovisual Guidance and Feedback / Sensor Glove / Sensor Suit (Fraunhofer IIS)


Wearable technologies dominate the roadmaps for the development of personal electronics and computing. Lessons learned from already marketed products lacking sustainable use emphasize the indispensability of substantial user benefit, the integration of wearable components into overall infrastructures including personalized services should be based on practicable business models. From the technology perspective, textile integration becomes increasingly relevant for (semi-) professional applications in healthcare and sports, but also enables novel attractive outfits. However, for autonomous operation, imperceptible integration of electronics as well as flexible and scalable functionality there are still a lot of challenges, but also solutions.

Energy Harvesting: Using a thermoelectric energy supply, Fraunhofer IIS presented the first Bluetooth Low Energy wristband with in April 2014. The BlueTEG sensor wristband measures e.g. ambient temperature or acceleration rates and transmits this data via Bluetooth LE to a smartphone or tablet PC. The temperature difference between the skin and the surrounding air is used to produce electrical energy for electronic systems by a conventional thermo generator and a special voltage converter. BlueTEG does not require a battery that needs to be recharged or exchanged, unlike conventional devices. The technology can be used with all types of bodyworn systems.

Imperceptible integration: The past years saw a number of approaches to realize stretchable electronic circuits. In the European STELLA project a fabrication technology for stretchable electronic systems has been developed by Fraunhofer IZM in cooperation with TU Berlin. The technology is derived from conventional printed circuit board manufacturing processes. Stretchability is achieved by using polyurethane as a carrier material for copper structures and a meandering design of circuit paths connecting commercial (rigid) electronic components. The boards can be extended by up to 300 percent before rupture of the copper interconnections. Systems thus realized can be attached to different surfaces, in particular
textiles by a simple lamination process.

Scalable functionality: A cooperation project of the Berlin University of the Arts, Fraunhofer IZM and a commercial partner resulted in a flexible and bendable lighting system that can be adapted to different shapes and easily extended to larger sizes. “Canvas” is composed of several layers, which realize specific optical, electrical and thermal properties and are connected in a lamination process. The electrical layer consists of a stretchable substrate with 256 white LEDs and surface-mounted lenses made from acrylic glass that can be controlled by a dimmer. This layer is back-covered by a knitted fabric made of metalized yarn, which is used to conduct the heat away from the electronics. For the top layer a non-conductive fabric that is structured by a deep drawing process is used to stabilize the underlying optics and to achieve an overall textile look and feel. When Canvas is moved or formed to different shapes new light patterns and light effects are created, making it attractive for many in- and outdoor applications. The project has been awarded 2010 with a textil+mode Innovation Award of the German Textile and Fashion Industry Association.

Figure 3. Textile Lighting / Smart Textile Examples (Fraunhofer IZM)

Figure 3. Textile Lighting / Smart Textile Examples (Fraunhofer IZM)

Textile integration can contribute to success of future wearable solutions addressing health-related and professional use-cases including personalized services based on practicable business models.