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Author

Ivo Locher

Bio: Ivo Locher is an academic researcher from ETH Zurich. The author has contributed to research in topics: Printed circuit board & Wearable computer. The author has an hindex of 11, co-authored 23 publications receiving 1057 citations. Previous affiliations of Ivo Locher include University of Pisa & University of California, Los Angeles.

Papers
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Journal ArticleDOI
TL;DR: In this paper, four purely textile patch antennas for Bluetooth applications in wearable computing using the frequency range around 2.4 GHz were presented, which can withstand clothing bends down to a radius of 37.5 mm without violating the Bluetooth specifications.
Abstract: In this paper, we present four purely textile patch antennas for Bluetooth applications in wearable computing using the frequency range around 2.4 GHz. The textile materials and the planar antenna shape provide a smooth integration into clothing while preserving the typical properties of textiles. The four antennas differ in the deployed materials and in the antenna polarization, but all of them feature a microstrip line as antenna feed. We have developed a manufacturing process that guarantees unaffected electrical behavior of the individual materials when composed to an antenna. Thus, the conductive textiles possess a sheet resistance of less than 1Omega/squarein order to keep losses at a minimum. The process also satisfies our requirements in terms of accuracy meeting the Bluetooth specifications. Our investigations not only characterize the performance of the antennas in planar shape, but also under defined bending conditions that resemble those of a worn garment. We show that the antennas can withstand clothing bends down to a radius of 37.5 mm without violating specifications

446 citations

Proceedings Article
01 Jan 2004
TL;DR: In this article, a navel circularly polarized (CP) textile patch antenna is presented, which uses truncated carners along with a single slit in patch to achieve proper CP operation.
Abstract: A navel circularly polarized (CP) textile patch antenna is presented in this paper. To our knowledge, it is the first textile antenna with circular polarization and for the first time, we show that more sophisticated design methods are also applicable to flexible textile antennas. The antenna uses a single inset microstrip feed-line. To achieve proper CP operation, truncated carners along with a single slit in patch are applied. The 3-dB axial-ratio CP bandwidth is about 3%, which represents a very good result even compared to standard, hard substrate CP antennas.

105 citations

Journal ArticleDOI
Ivo Locher1, Gerhard Tröster1
TL;DR: This work presents transmission lines structures that were screen-printed on fabrics that featured a sheet resistance of about 0.15 Ω/, while preserving the flexible nature of textiles and proposes an advanced printing technique as outlook.
Abstract: Electronic fabrics is an emerging topic in the field of smart textiles. We present transmission lines structures that were screen-printed on fabrics. They featured a sheet resistance of about 0.15 ...

104 citations

Proceedings ArticleDOI
07 Oct 2002
TL;DR: The system design of "Smart Kindergarten", a smart problem solving environment for early childhood education, is described and the design challenges of iBadge and Sylph are presented and the efforts in integrating these two systems are presented.
Abstract: We describe the system design of "Smart Kindergarten", a smart problem solving environment for early childhood education. Two crucial building blocks that make up smart kindergarten are iBadge, a lightweight power-aware sensor-instrumented badge, and Sylph, a sensor middleware infrastructure. Equipped with sensors, radio, and DSP, iBadge has been designed to be worn by kids and teachers to unobtrusively capture the interaction between the kids and their surroundings. The captured data is then wirelessly transmitted to Sylph, a middleware infrastructure, which provides means of accessing the data in coherent and user-friendly manner. In this paper, we present the design challenges of iBadge and Sylph and our efforts in integrating these two systems.

84 citations

Journal ArticleDOI
01 Sep 2005
TL;DR: An already developed organic field-effect transistor that is realized on a flexible film that can be applied on whatever kind of substrate, in particular, on textiles could pave the way to a variety of applications aimed to conjugate the favorable mechanical properties of textiles with the electronic functions of transistors.
Abstract: In this paper, several issues concerning the development of textiles endowed with electronic functions will be discussed. In particular, issues concerning materials, structures, electronic models, and the mechanical constraints due to textile technologies will be detailed. The idea starts from an already developed organic field-effect transistor that is realized on a flexible film that can be applied, after the assembly, on whatever kind of substrate, in particular, on textiles. This could pave the way to a variety of applications aimed to conjugate the favorable mechanical properties of textiles with the electronic functions of transistors. Furthermore, a possible perspective for the developments of organic sensors based on this structure are described.

79 citations


Cited by
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Journal ArticleDOI
Wei Zeng1, Lin Shu1, Qiao Li1, Song Chen1, Fei Wang1, Xiaoming Tao1 
TL;DR: This article attempts to critically review the current state-of-arts with respect to materials, fabrication techniques, and structural design of devices as well as applications of the fiber-based wearable electronic products.
Abstract: Fiber-based structures are highly desirable for wearable electronics that are expected to be light-weight, long-lasting, flexible, and conformable Many fibrous structures have been manufactured by well-established lost-effective textile processing technologies, normally at ambient conditions The advancement of nanotechnology has made it feasible to build electronic devices directly on the surface or inside of single fibers, which have typical thickness of several to tens microns However, imparting electronic functions to porous, highly deformable and three-dimensional fiber assemblies and maintaining them during wear represent great challenges from both views of fundamental understanding and practical implementation This article attempts to critically review the current state-of-arts with respect to materials, fabrication techniques, and structural design of devices as well as applications of the fiber-based wearable electronic products In addition, this review elaborates the performance requirements of the fiber-based wearable electronic products, especially regarding the correlation among materials, fiber/textile structures and electronic as well as mechanical functionalities of fiber-based electronic devices Finally, discussions will be presented regarding to limitations of current materials, fabrication techniques, devices concerning manufacturability and performance as well as scientific understanding that must be improved prior to their wide adoption

1,626 citations

Journal ArticleDOI
TL;DR: CAS will be able to provide a substantial contribution to the development of sensor networks, and has already been designed to test the many ideas spawned by the research community and to implement applications to virtually all fields of science and technology.
Abstract: Sensor networks offer a powerful combination of distributed sensing, computing and communication. They lend themselves to countless applications and, at the same time, offer numerous challenges due to their peculiarities, primarily the stringent energy constraints to which sensing nodes are typically subjected. The distinguishing traits of sensor networks have a direct impact on the hardware design of the nodes at at least four levels: power source, processor, communication hardware, and sensors. Various hardware platforms have already been designed to test the many ideas spawned by the research community and to implement applications to virtually all fields of science and technology. We are convinced that CAS will be able to provide a substantial contribution to the development of this exciting field.

641 citations

Journal ArticleDOI
TL;DR: In this article, a wearable activity recognition system is proposed to recognize human activities from body-worn sensors, which can further open the door to a world of healthcare applications, such as fitness monitoring, eldercare support, long-term preventive and chronic care, and cognitive assistance.
Abstract: Activity-aware systems have inspired novel user interfaces and new applications in smart environments, surveillance, emergency response, and military missions. Systems that recognize human activities from body-worn sensors can further open the door to a world of healthcare applications, such as fitness monitoring, eldercare support, long-term preventive and chronic care, and cognitive assistance. Wearable systems have the advantage of being with the user continuously. So, for example, a fitness application could use real-time activity information to encourage users to perform opportunistic activities. Furthermore, the general public is more likely to accept such activity recognition systems because they are usually easy to turn off or remove.

634 citations

Journal ArticleDOI
TL;DR: A review of recent developments in the rapidly changing and advancing field of smart fabric sensor and electronic textile technologies can be found in this article, which summarizes the basic principles and approaches employed when building fabric sensors as well as the most commonly used materials and techniques used in electronic textiles.
Abstract: This paper provides a review of recent developments in the rapidly changing and advancing field of smart fabric sensor and electronic textile technologies. It summarizes the basic principles and approaches employed when building fabric sensors as well as the most commonly used materials and techniques used in electronic textiles. This paper shows that sensing functionality can be created by intrinsic and extrinsic modifications to textile substrates depending on the level of integration into the fabric platform. The current work demonstrates that fabric sensors can be tailored to measure force, pressure, chemicals, humidity and temperature variations. Materials, connectors, fabric circuits, interconnects, encapsulation and fabrication methods associated with fabric technologies prove to be customizable and versatile but less robust than their conventional electronics counterparts. The findings of this survey suggest that a complete smart fabric system is possible through the integration of the different types of textile based functional elements. This work intends to be a starting point for standardization of smart fabric sensing techniques and e-textile fabrication methods.

618 citations

Journal Article
TL;DR: In this paper, a personal activity recognition system based on a cell phone platform augmented with a Bluetooth-connected sensor board is proposed to recognize 8 different activities collected from 12 different subjects.
Abstract: We are developing a personal activity recognition system that is practical, reliable, and can be incorporated into a variety of health-care related applications ranging from personal fitness to elder care. To make our system appealing and useful, we require it to have the following properties: (i) data only from a single body location needed, and it is not required to be from the same point for every user; (ii) should work out of the box across individuals, with personalization only enhancing its recognition abilities; and (iii) should be effective even with a cost-sensitive subset of the sensors and data features. In this paper, we present an approach to building a system that exhibits these properties and provide evidence based on data for 8 different activities collected from 12 different subjects. Our results indicate that the system has an accuracy rate of approximately 90% while meeting our requirements. We are now developing a fully embedded version of our system based on a cell-phone platform augmented with a Bluetooth-connected sensor board.

588 citations