03-11-2012, 05:26 PM
A Seminar Report On Electronic Textiles
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INTRODUCTION
Intelligent textiles, variously known as smart fabrics, electronic textiles, or e-textiles, have attracted considerable attentions worldwide due to their potential to bring revolutionary impacts on human life.
Electronic textiles (e-textiles) are fabrics that have electronics and interconnections woven into them. Components and interconnections are a part of the fabric and thus are much less visible and, more importantly, not susceptible to becoming tangled together or snagged by the surroundings. Consequently, e-textiles can be worn in everyday situations where currently available wearable computers would hinder the user. E-textiles also have greater flexibility in adapting to changes in the computational and sensing requirements of an application. The number and location of sensor and processing elements can be dynamically tailored to the current needs of the user and application, rather than being fixed at design time.
Electronic textiles, also described as smart fabrics in popular media, have become quite a fashionable research area. An electronic textile refers to a textile substrate that incorporates capabilities for sensing (biometric or external), communication (usually wireless), power transmission, and interconnection technology to allow sensors or things such as information processing devices to be networked together within a fabric. This is different from the smart textiles that feature scientific advances in materials research and include things such as better insulators or fabrics that resist stains. Electronic textiles allow little bits of computation to occur on the body. They usually contain conductive yarns that are either spun or twisted and incorporate some amount of conductive material (such as strands of silver or stainless steel) to enable electrical conductivity.
Electronics textile or e-textile belongs to the category of newly emerging discipline in the field of research, which combines specialists in respective discipline of information technology, Microsystems, materials and textiles. The emphasis of this upcoming area is aimed at developing the enabling technologies and fabrication techniques for the economical production of large area and conformable information systems that are estimated to have multiple applications in both consumer electronics and military industry.
HISTORY OF ELECTRONIC TEXTILES
In the past, clothing-containing electronics was only portrayed in the world of science fiction. The merging of textiles and technology has made electronic textiles an exciting new reality. The idea of integrating electronics into our textile and apparel products is no longer science fiction. Textile-based computing is currently being developed, allowing the wearer to easily move audio, data, and power around a garment or textile. These specialized textiles have the potential to keep us connected, informed, and entertained without the need to carry any electronic devices. Interactive touch, voice, and body heat activated wearable electronics are being developed and are gradually appearing on store shelves. The development of these items is fueled by the increasing desire for mobile devices that will allow us to access information anywhere and at anytime.
One of the first efforts in e-textiles, performed at MIT, consisted of conductive metallic organza integrated into fabric to create interactive fabrics. The first interactive fabric was a row and column based musical keyboard. The resulting device was flexible enough to be folded and was capable of emitting the appropriate keyboard notes via external speakers.
Row and column fabric keyboard:
The row and column fabric keyboard (Figure 1) is a fabric switch matrix sewn from conducting and no conducting fabric. The keyboard
consists of two layers of highly conductive metallic organza with a resistance of approximately 10 V/m (ohm/meter) and non conducting rows separated by an insulating layer of nylon netting (also known as tulle). When pressed at the right point, the two conducting layers make contact through spaces in the nylon netting and current flows from a row electrode to a column electrode. Commercial gripper snaps are used to connect wires from a microcontroller to the organza. The keyboard can be repeatedly rolled up, crushed, or washed without affecting its electrical properties.
Levis/Philips ICD+ jacket:
The Levis ICD+ jacket (Figure 2) was launched commercially in summer 2000 and this product is widely considered to be the first commercial wearable electronics garment.
The patented ICD jacket was designed in four styles and all had a removable wired harness connecting a range of portable electronic devices carried by young professional people. The jacket had strategic pockets for the Philips Xenium mobile phone (Figure 3), Rush MP3 player and earphones along with purpose built channels for the wiring through the garment. A central control module connected all the devices to allow the wearer to switch between them and control their separate functions. A personal area network (PAN) provides the backbone for connecting these electronics. Concealed inner wiring and connectors in the fabric allow the devices to operate by remote control.
MAKING OF E-TEXTILES
The tactile and aesthetic properties of textile and apparel products are important to consumers. Many are reluctant to wear bulky gadgetry or have wires and hard plastic cases containing electronics against their bodies. In the effort to develop lighter more appealing wearable devices, conductive materials are being used to transform traditional textile and apparel products into fashionable, desirable, lightweight, wireless wearable computing devices. A material, such as metallic and optical fibers, conductive threads, yarns, fabrics, coatings and inks are being used to supply conductivity and create wireless textile circuitry.
Metallic and Optical fibers:
Electronic textiles can be created by using minute electrically conductive fibers. Electrically conductive fibers can be classified into two general categories, those that are naturally conductive and those that are specially treated to create conductivity. Naturally, conductive fibers or metallic fibers are developed from electrically conductive metals such as ferrous alloys, nickel, stainless steel, titanium, aluminum, copper, and carbon. Metal fibers are very thin metal filaments, with diameters ranging from 1 to 80 microns (μm).
A thread developed from steel and polyester fibers is shown in Figure 7, while a 100% stainless steel thread is illustrated in Figure 8. Metallic fibers are highly conductive; however, they expensive and their brittle characteristics can damage spinning machinery over time. In addition, they are heavier than most textile fibers making homogeneous blends difficult to produce.
PROPERTIES OF E – TEXTILES
Electrical properties:
From the electrical points of view, conductivity is the most important factor. Electrical resistance low enough to allow a flow of electric energy, such as for power or data transmission, is critical. Metal, carbon, or optical fibers are typically well-known conductors. Conductive yarns are either pure metal yarns or composites of metals and textiles. Metals are superior in strength and fineness, and textiles are selected for comfort. In order to produce a successful conductive yarn, the best mix of conductive and non-conductive materials is critical. As a thread takes on a bigger portion of conductive components, it loses the typical textile properties such as flexibility or drivability and becomes more conductive. The achievement in electrical resistance has ranged from 0.2441 ohms per meter (Ω/m) to 5,000 Ω/m.
Mechanical properties:
From the textile point of view, e-textiles need to be designed to exhibit physical properties similar to those of traditional textiles. E-textiles should be bendable, stretchable, and washable while keeping good electrical conductivity. To develop practical wearable systems, mechanical properties of e-textiles are critical. However, there has been very little research that systematically evaluates the physical behaviour of e-textiles.
Flexibility:
Flexibility can be understood as the resistance to permanent deformation under stresses such as folding or bending. Flexibility of yarns can be improved through textile processes such as spinning or twisting because the overall geometry of the yarn is a prior factor to those of individual fibers. Generally, yarn flexibility is affected by an individual fiber's characteristics, such as fineness, flatness or Young's modulus; percentage of conductive fibers; and their geometry.
[attachment=38126]
[attachment=38127]
INTRODUCTION
Intelligent textiles, variously known as smart fabrics, electronic textiles, or e-textiles, have attracted considerable attentions worldwide due to their potential to bring revolutionary impacts on human life.
Electronic textiles (e-textiles) are fabrics that have electronics and interconnections woven into them. Components and interconnections are a part of the fabric and thus are much less visible and, more importantly, not susceptible to becoming tangled together or snagged by the surroundings. Consequently, e-textiles can be worn in everyday situations where currently available wearable computers would hinder the user. E-textiles also have greater flexibility in adapting to changes in the computational and sensing requirements of an application. The number and location of sensor and processing elements can be dynamically tailored to the current needs of the user and application, rather than being fixed at design time.
Electronic textiles, also described as smart fabrics in popular media, have become quite a fashionable research area. An electronic textile refers to a textile substrate that incorporates capabilities for sensing (biometric or external), communication (usually wireless), power transmission, and interconnection technology to allow sensors or things such as information processing devices to be networked together within a fabric. This is different from the smart textiles that feature scientific advances in materials research and include things such as better insulators or fabrics that resist stains. Electronic textiles allow little bits of computation to occur on the body. They usually contain conductive yarns that are either spun or twisted and incorporate some amount of conductive material (such as strands of silver or stainless steel) to enable electrical conductivity.
Electronics textile or e-textile belongs to the category of newly emerging discipline in the field of research, which combines specialists in respective discipline of information technology, Microsystems, materials and textiles. The emphasis of this upcoming area is aimed at developing the enabling technologies and fabrication techniques for the economical production of large area and conformable information systems that are estimated to have multiple applications in both consumer electronics and military industry.
HISTORY OF ELECTRONIC TEXTILES
In the past, clothing-containing electronics was only portrayed in the world of science fiction. The merging of textiles and technology has made electronic textiles an exciting new reality. The idea of integrating electronics into our textile and apparel products is no longer science fiction. Textile-based computing is currently being developed, allowing the wearer to easily move audio, data, and power around a garment or textile. These specialized textiles have the potential to keep us connected, informed, and entertained without the need to carry any electronic devices. Interactive touch, voice, and body heat activated wearable electronics are being developed and are gradually appearing on store shelves. The development of these items is fueled by the increasing desire for mobile devices that will allow us to access information anywhere and at anytime.
One of the first efforts in e-textiles, performed at MIT, consisted of conductive metallic organza integrated into fabric to create interactive fabrics. The first interactive fabric was a row and column based musical keyboard. The resulting device was flexible enough to be folded and was capable of emitting the appropriate keyboard notes via external speakers.
Row and column fabric keyboard:
The row and column fabric keyboard (Figure 1) is a fabric switch matrix sewn from conducting and no conducting fabric. The keyboard
consists of two layers of highly conductive metallic organza with a resistance of approximately 10 V/m (ohm/meter) and non conducting rows separated by an insulating layer of nylon netting (also known as tulle). When pressed at the right point, the two conducting layers make contact through spaces in the nylon netting and current flows from a row electrode to a column electrode. Commercial gripper snaps are used to connect wires from a microcontroller to the organza. The keyboard can be repeatedly rolled up, crushed, or washed without affecting its electrical properties.
Levis/Philips ICD+ jacket:
The Levis ICD+ jacket (Figure 2) was launched commercially in summer 2000 and this product is widely considered to be the first commercial wearable electronics garment.
The patented ICD jacket was designed in four styles and all had a removable wired harness connecting a range of portable electronic devices carried by young professional people. The jacket had strategic pockets for the Philips Xenium mobile phone (Figure 3), Rush MP3 player and earphones along with purpose built channels for the wiring through the garment. A central control module connected all the devices to allow the wearer to switch between them and control their separate functions. A personal area network (PAN) provides the backbone for connecting these electronics. Concealed inner wiring and connectors in the fabric allow the devices to operate by remote control.
MAKING OF E-TEXTILES
The tactile and aesthetic properties of textile and apparel products are important to consumers. Many are reluctant to wear bulky gadgetry or have wires and hard plastic cases containing electronics against their bodies. In the effort to develop lighter more appealing wearable devices, conductive materials are being used to transform traditional textile and apparel products into fashionable, desirable, lightweight, wireless wearable computing devices. A material, such as metallic and optical fibers, conductive threads, yarns, fabrics, coatings and inks are being used to supply conductivity and create wireless textile circuitry.
Metallic and Optical fibers:
Electronic textiles can be created by using minute electrically conductive fibers. Electrically conductive fibers can be classified into two general categories, those that are naturally conductive and those that are specially treated to create conductivity. Naturally, conductive fibers or metallic fibers are developed from electrically conductive metals such as ferrous alloys, nickel, stainless steel, titanium, aluminum, copper, and carbon. Metal fibers are very thin metal filaments, with diameters ranging from 1 to 80 microns (μm).
A thread developed from steel and polyester fibers is shown in Figure 7, while a 100% stainless steel thread is illustrated in Figure 8. Metallic fibers are highly conductive; however, they expensive and their brittle characteristics can damage spinning machinery over time. In addition, they are heavier than most textile fibers making homogeneous blends difficult to produce.
PROPERTIES OF E – TEXTILES
Electrical properties:
From the electrical points of view, conductivity is the most important factor. Electrical resistance low enough to allow a flow of electric energy, such as for power or data transmission, is critical. Metal, carbon, or optical fibers are typically well-known conductors. Conductive yarns are either pure metal yarns or composites of metals and textiles. Metals are superior in strength and fineness, and textiles are selected for comfort. In order to produce a successful conductive yarn, the best mix of conductive and non-conductive materials is critical. As a thread takes on a bigger portion of conductive components, it loses the typical textile properties such as flexibility or drivability and becomes more conductive. The achievement in electrical resistance has ranged from 0.2441 ohms per meter (Ω/m) to 5,000 Ω/m.
Mechanical properties:
From the textile point of view, e-textiles need to be designed to exhibit physical properties similar to those of traditional textiles. E-textiles should be bendable, stretchable, and washable while keeping good electrical conductivity. To develop practical wearable systems, mechanical properties of e-textiles are critical. However, there has been very little research that systematically evaluates the physical behaviour of e-textiles.
Flexibility:
Flexibility can be understood as the resistance to permanent deformation under stresses such as folding or bending. Flexibility of yarns can be improved through textile processes such as spinning or twisting because the overall geometry of the yarn is a prior factor to those of individual fibers. Generally, yarn flexibility is affected by an individual fiber's characteristics, such as fineness, flatness or Young's modulus; percentage of conductive fibers; and their geometry.