(Lecturer, Deptt. Of Textile Technology, PSG College of Technology, Coimbatore, INDIA
Technology is getting smaller and faster and we all know the speed of this development is increasing. We see an ongoing miniaturization and production of materials equipped with special properties. It is possible to integrate properties of sensitivity, information and intelligence into single materials. The materials of our surroundings are being intellectualized. Whereas, in the past, we needed several components to satisfy a certain function, technology today has allowed us to satisfy the same function with fewer components. These materials can interact, communicate and sense. Miniaturization not only means the production of smaller components, but the elimination of components. Formerly people had a traditional relationship with materials, but new materials do not have a known image of themselves. People have had to change from perceiving with cultural and physical depth to perceiving appearances. Therefore materials and objects today are not what they actually are, but what they seem to be and the performance they offer. Our everyday life is being more and more regulated by intelligent devices. Making a system of intelligent objects is one of the most important trends in contemporary engineering and design.
Advances in textile technology, computer engineering, and materials science are promoting a new breed of functional fabrics. Fashion designers are adding wires, circuits, and optical fibers to traditional textiles, creating garments that glow in the dark or keep the wearer warm. Meanwhile, electronics engineers are sewing conductive threads and sensors into body suits that map users whereabouts and respond to environmental stimuli. Researchers agree that the development of genuinely interactive electronic textiles is technically possible, and that challenges in scaling up the handmade garments will eventually be overcome.
The vision behind the idea of wearable electronics systems describes future electronic systems as an integral part of our everyday clothing, serving us as intelligent personal assistants. A wearable electronics garment is always on, does not hinder the user's activities, has easy-to-use interfaces, is aware of the user's situation and provides support, e.g. by displaying relevant information, monitoring health parameters and augmenting the user's view of reality. The possible systemization of wearable electronics consists of the components of a wearable system that provide several functions:
sensor unit: registration of biometric and environmental data and of user commands
network unit: transmission of data within the wearable computer and to external networks
processing unit: calculating, analyzing and storing data
Power unit: supplying. energy
Actuator unit: adapting to situations, creating an effect on the user, displaying data.
The wearable electronics clothing functions like a motherboard, with plastic optical fibers and other specialty fibers woven throughout the actual fabric of the shirt. The flexible bus can transmit critical information to and from the soldiers. The smart shirt is highly useful in detecting the number of bullet wounds and to send the vital signs like temperature rate, pulse rate, blood pressure rate to the remote centre. And also it can help a physician to determine the extent of a soldiers injuries based on the strength of his temperature and heart beat. This information is vital for accessing who needs first assistance during the so called Golden Hour in which there is numerous causalities.
Communication plays a vital role in the defence field; conventional method of communication is too complicated and massive in weight. Since they consist of heavy batteries, lengthier antennas, heavy control box, heavy head phone and discomfort method of operation. Whereas Wearable Electronics clothing eliminates all this hurdles by means of tiny integrated communication circuits. The power can be generated from the usual body movements and by using accumulator circuits.
Initially the clothes will be powered by a rechargeable battery, like those in mobile phones, but eventually we can trap the natural heat given off by the body. This will generate about 100 watts as the basic source of power. With this unique mix of electronic and textile technology we can produce an entirely new clothing concept WEARABLE ELECTRONICS. A fabric keypad for communication purpose can also be incorporated in this. Mobile phone technology and miniature cameras could be combined with the clothing in order to allow the defence personnel to track wherever they are and to monitor what they are doing. This paper deals about the prospective of generating power from the body movements and competent placement of placing the powered batteries in the wearable electronics garments, so that it will not be hindrance to the wearer. It also describes about the possibilities of integrating solar cells in the garment.
1.0 INTRICACIES OF POWER SUPPLY
The power supply is the heaviest part the biggest problem, two of the most known approaches to develop new power supply technologies, are lithium polymer battery and micro fuel cells. Sunlight, body temperature and body motion are alternative energy sources on the body that can be transformed into electrical energy. Also in this case, one should differ between flexible and textile, because there are more efforts to mount flexible energy supplies onto textiles than inventing pure textile power supply. The temperature difference between the outside and the inside of clothing can produce a power of a few microwatts per cm.
Thin film solar cells can be made on flexible surfaces such as plastics. The flexible solar cell technology has also been adapted to fiber form. The efficiency of these alternative energy sources needs to be improved. Creating components that are wirelessly powered by an electric field in the environment is another interesting approach.
2.0 BODY POWER GENERATION
This circuit has been generated to develop the concept of wearable electronics clothing that will be able to power the equipment the soldiers currently use, to monitor soldiers body during combat situations, etc. The continuous supply of power is required for the circuits used in the garment and for communication. In the conventional system, heavy sized batteries weighing around 12 Kgs being carried for communication purposes.
Above requirements can be resolved by incorporating a novel idea to generate power from body movements. This will purge the conventional method of carrying massive batteries and by this way continuous power can be supplied for the circuits used in the garment. The circuit for power generation circuit is embedded in the soldiers pants. Normally this system generates 5 Volts, the generated voltage is connected to a special type of chemical rechargeable battery which is placed in the sole part of the shoes; the battery weight is negligible when compared with conventional type of batteries. The placement of the fixed magnets and induction coil is shown in the Figure 1
2.1 POWER GENERATION SYSTEM
Figure 1.1 shows the block diagram of the power generation system. It consists of two units. One unit is packed and stitched with fixed magnet arrangement and another unit is packed and stitched with induction coil arrangement. Output pins are provided for tapping the power from this system.
The unit is stitched in a suitable manner so that there is no discomfort to soldier.
FIG 1: BLOCK DIAGRAM OF THE POWER GENERATION SYSTEM
The coil is wounded for three cycles on the aluminum foil.At first the coil is wounded parallel to the horizontal axis of the foil, for the second cycle it is wounded in a crossed manner, next upon the crossed wound coil it is again wound parallel to the horizontal axis of the plate. Figure1 shows the schematic diagram of the power generation system in which there is fixed magnetic arrangement and there is a coil arrangement. From the coil arrangement power is tapped and given as an input to the AC to DC converter unit. After DC conversion the supply is given to the output pins.
Block diagram of the power generation system consist of two units. One is the Magnetic plates and the second one is the coil arrangement. According to Faradays Law of Electromagnetic Induction, whenever a conductor cuts magnetic lines of flux, an emf is induced in the conductor. In this novel technology, triangular magnet pieces of size 6 mm x 2.5 mm x 18mm filled with Gellodium is used as Permanent Magnet. Aluminum sheet wounded with conductive coils were used as conductor. When a soldier walks, coil cuts the magnetic flux lines; due to this an emf will be generated. The tapped emf can be used to activate external circuits like mobile phone, PDA or the circuits used in our garment. This emf can be given as input to the special batteries kept inside the sole of the shoes.
2.2 POWER SHOES
The Power shoes were our experimental method to generate the power to be used for the circuits. Accumulator can also be called as chemical rechargeable battery which is the resource of power for all circuits. It is placed inside the sole of the shoes. It gives continuous constant power supply for the circuits to operate and it can be used for 6 hours without recharging. Soldier would not feel any discomfort while walking or running because of the arrangement of accumulator inside the shoes.
The complete arrangement is just like a rechargeable battery which is connected in series with the power generation circuit. The generated power from this circuit will be supplied to this power shoes. It will be charged while walking. From this rechargeable circuit all the other circuits can get power.
3.0 WEARABLE LIGHT FIBRE ANIMATION
PMMA is one of the Plastic optical fiber. It is used for Telecommunication of data transfer by using its end emitting characteristics. Polymeric optical fiber (POF) is used for simple light guide and illumination applications. The polymer optical fiber materials can be utilized in flexible lighting elements which can be combined with textile structures. The POF woven fabrics are introduced as a flexible alternative to lighting elements.
PMMA and polycarbonate (PC) fibers have been produced experimentally through single-screw and conical extrusion. The fiber is integrated in woven structures by means of handloom, narrow fabric weaving and Jacquard technology. This material can be used as flexible lighting elements by converting them into surface emitting property, it can also be combined with textile structures in a specific weave patterns as a flexible alternate to lighting elements. Flexible display units may provide new possibilities for creative design, protective clothing and industrial art applications.
The illuminated system is prepared by connecting the ends of woven fabric into the fiber optic cable to LED; this system is in turned to a battery of 3 V. The illuminated system is stitched into a specific location in silhouette of the garment, construction of garment panels are made with high speed lock stitch sewing machine of Class 300 stitches. Fig 2 shows the prototype of illuminated clothing system.
FIG 2 ILLUMINATED CLOTHING PROTOTYPE
The illuminated clothing system is a design and developed for safety and protective purposes. It is possible to produce the woven fabric using PMMA for the purpose of glowing effect with slight modification in the weave geometry. The sateen weave shows better illumination when compared to twill fabric, the structure of sateen weave has more weft float. Since the weft bending angle is less that causes more illumination when compared to twill fabric. The illumination effect on clothing system is also influenced by the different colors of LEDs; the wavelength of different colors influences the illumination.
It can be implemented for the applications like, transferring the images or text from a mobile phone to the optical fiber screen of the garment to bring animated effect. It is possible to vary the brightness of optic fiber screen according to the sound environment, using low frequency sensitive circuit. The light may get brighter each time, when wearer clap their hands or stamp their feet. Further work can also be carried out in medical textile by using this material as surgical tool for photo therapy system.
4.0 DEVELOPMENT OF ELECTRIC SWEATER
The idea behind the project is to generate heat by means of heating coils; the coils were integrated with textile garment. Nickel Chromium alloy (Ni-chrome) in wire form is used as heat generating coils. The Ni-chrome wire has a special property of generating heat when a difference voltage is applied. This property is used to generate heat. The Ni-chrome integrated garment will be embedded with an electronic circuitry which consists of, microcontroller, Temperature sensor, wires, etc.
Two temperature sensors are used in the garment. One is to measure the body heat, and another is to measure the temperature of heating filament. Body temperature measuring sensor is placed near the armhole portion of the garment and another one is fixed with the heating filament. The heat generated in the coil should not exceed a limit and should be controlled. For this purpose a second temperature sensor is used.
Power supply is connected to the Ni-chrome coils through a 6 Volt relay. The relay is triggered by microcontroller. Both the temperature sensors are connected to the microcontroller to monitor the temperature. The microcontroller is programmed to measure the temperature of both temperature sensors at every second. Whenever the body temperature falls below certain limit, microcontroller will trigger the relay thereby giving electric supply to Ni-chrome wires. The supply will generate heat in wires. The heat generated will be dissipated by cotton to the entire body. Whenever the temperature exceeds the upper limit the power supply will be cut off.
5.0 THE CONCEPT OF ELECTROTEXTILES
Electronic means that a system is able to exchange and process information. If textiles had the ability to record, analyse, store, send and display data, a new dimension of intelligent high-tech clothing could be reached. The wearability totally depends on the way of integration into clothing: miniaturization of electronic components and attachment to textiles development of textiles with electronic functions.
Electrotextiles are fabrics made from yarns that carry electronic components. Circuits are made from such yarns by weaving. We describe the technical development of the concept of e-textiles, and briefly discuss three challenges: connectivity, materials and fabrication, and wear. Wearable electronics and electronic textiles lie at the two ends of a spectrum that ranges from added-on electronics to components integrated with textile yarn to true integration.
5.1 TECHNOLOGY OF ELECTROTEXTILES
The technology of electro textiles is found mainly in military applications, an example antenna woven into soldiers' vests. But commercial products are starting to appear. "People are developing radios only two or three millimeters big that can be incorporated into washable electro textiles, The soft, flexible fibers woven into the electro textiles aren't meant to light up floor lamps, but they are conductive enough to transmit signals. Whether they are intended for soldiers or civilians, electro textiles in their current incarnations require an external power source, normally a battery.
The transparent photovoltaic and washable fibre developed at the University Stuttgart is a solar cell which is to wear like clothes. It is made of plastic fibre, glass fibre and wire threefold coated in amorphous silicon and its purpose is to produce energy. Wearable computers/electronic devices are either attached applications or they use existing niches for the integration of technology, whereas electro textiles do not influence the design of the clothes but as a fabric that may take every shape provides clothing with additional functions.
It's seen as boon to the military for a variety of reasons. War fighters could cut their battery load weight in half when PV cells are used in combination with rechargeable batteries to power individual items such as night vision goggles, Less weight means better mobility, and the ability to recharge batteries on-the-move can increase sustainability, extend mission times and distance from tactical operations centers, and reduce logistics support requirements. Replacing or decreasing the number of liquid-fuel-powered generators further reduces logistics, and lowers the heat and sound signature in the field for improved stealth. It's also a potential lifesaver as an emergency back-up power in case generators fail, say, in a field hospital. These benefits are possible because of new lightweight and flexible solar cells made with two complementary PV technologies, amorphous silicon and dye-sensitized Nan composites.
5.2 IMPORTANT OF ELECTROTEXTILES
The mobility aspect of wearable is what makes it unique as a medium for communication. Today, mobility is a fundamental aspect of many services and devices. There is an almost unlimited number of application ideas, e.g. in the fields of health, knowledge and entertainment. Health applications include the monitoring of ill or high-risk persons, people exposed to extreme conditions or people doing sports. This also applies to therapy and improvement of physical abilities. A wearable computer is always on, should not hinder the users activities, can be aware of the users situation and can display relevant information, augmenting ones view of reality. The vision for wearable computing is to be an integrated part of our everyday clothing serving us as intelligent personal assistants.
6.0 FUTURE PLANS FOR POWER GENERATION
The power generating unit is the heart of wearable electronics. The functionality of the device and its economics are highly based on the power generating systems. We are planning lot of projects for generating the power from natural sources like body heat and sun.
6.1 FLEXIBLE SOLAR CELLS
Sunlight is the bright filling station above that never asks for money or runs out of fuel for photovoltaic products, and some scientists believe that the sky is the limit for a new generation of photovoltaic technologies in development. A promising technology that's existed for decades, photovoltaic solar cells converts light energy into electricity without noise, moving parts, and fuel consumption or pollutant emissions. A breakthrough arrived in the past five years when PV technology transformed from the traditional large, heavy, rigid, reflective and expensive glass panels into lightweight, conformal and inexpensive devices that now can be directly integrated into textiles and for military applications.
Integration of flexible solar cells into clothing can provide power for portable electronic devices. Photovoltaic is the most advanced way of providing electricity far from any mains supply, although it suffers from the limits of ambient light intensity. But the energy demand of portable devices is now low enough that clothing-integrated solar cells are able to power most mobile electronics.
6.2 POWER-GENERATING SOLAR FABRIC
In a new twist on the concept of the power suit, InnovativeTechnolgies are used to develop a woven fabric that can harvest energy from the sun. The overall goal of the project is to develop a functional textile constructed out of fibers with photovoltaic, or solar-energy, and properties. Ultimately, the fabric could be used to create tents with interior lights or pants and backpacks that could charge cell phones. The goal is to create a fabric with 4% efficiency, meaning it could turn 4% of the sunlight hitting it into electric power. The rigid silicon solar panels on top of some downtown buildings are much more efficient. A few companies have developed flexible solar cells that can be used to wrap buildings or even coat bolts of cloth. The new project differs in that the solar harvesting capabilities would be woven into the material, ideally allowing the fabric to behave more like normal fabric. .The cells will be incorporated into foldable pads for recharging electronic devices. "This unique solar fabric represents a leap forward for photovoltaic technology,. It will enable power generation capabilities to be woven in rather than applied.
6.3 MOBILE COMMUNICATION WITH SOLAR CELLS IN CLOTHING
The Innovative technology of integerating flexible solar cells which on the shoulder section of the can be used as the power generating source for mobile communication. There are 72 extremely efficient flexible solar cells, capable of generating sufficient energy to power integrated communications technologies such as a minidisk player, a portable CD player, an electronic organizer or mobile phone. The cells are also capable of supplying power for other applications such as watches, pocket computers or even notebooks. This system currently contains conventional rigid solar cells made from crystalline silicon, but in future, these will be replaced with flexible thin solar cells. Energy generated by the solar cells using ambient light is stored in a rechargeable battery using a charge controller. The individual devices can then be supplied with this electricity directly. To supply higher voltages, for example to operate or recharge mobile phones, a voltage transformer is also required.
6.4 SOLAR CELLS WILL DOUBLE AS CAMOUFLAGE
There is a wonder full scope for flexible solar cell in army application. The recent technology uses the renewable power sources for the Army from light-activated power polymers. Among other things, the plastic cells could let soldiers carry a few rechargeable batteries rather than numerous primary cells to power the electronics they carry into battle Special operations soldiers, for example, can carry 30 to 50 kgs of replacement batteries for night-vision goggles, GPS units, and two-way communicators. "They carry a daily supply of primary batteries, but limited power capacity and the continual need for resupply can limit the mobility, range, and mission length required for effective field operations." The new concept provides Nan materials to convert absorbed sunlight and indoor light into electrical energy. This direct-current electrical energy can be used immediately, stored for later use, or converted to other forms of energy. Traditional photovoltaic cells are made from rigid pieces of silicon. Now a days the solar cells are coatable, plastic, flexible photovoltaic that serve in many applications where traditional photovoltaic can't compete. The photovoltaic products are literally printed onto rolls of plastic. The process can imprint different colors on the photovoltaic material. A prototype tent under development for the military, for example, can be produced in camouflage colors. The cells can also be made with varying degrees of translucency. This photovoltaic material can be printed with the appropriate images while still maintaining their power generating capabilities, helping to protect soldiers in the field."
6. 5 'DENIM' SOLAR PANELS TO CLOTH FUTURE BUILDINGS
Buildings of the future could be "clothed" in a flexible, power-generating material that looks like denim. The Canadian company developing the material says it can be draped over just about any shape - greatly expanding the number of places where solar power can be generated. The inventors hope their power-generating material will enable architects to design complex, curvy buildings that can nevertheless carry solar cells. One day, consumer products such as personal stereos and cell phones might also harness "denim-power" to charge their batteries.
Unlike conventional solar cells, the new, cheap material has no rigid silicon base. Instead, it is made of thousands of inexpensive silicon beads sandwiched between two thin layers of aluminum foil and sealed on both sides with plastic. Each bead functions as a tiny solar cell, absorbing sunlight and converting it into electricity. The aluminum sheets give the material physical strength and act as electrical contacts.This body power generating device can be used in the smart textiles to power the electronic devices integrated into the clothing. This technology enables the compact and techno economic system of wearable electronics
The mobility aspect of wearables is what makes it unique as a medium for communication. Today, mobility is a fundamental aspect of many services and devices. There is an almost unlimited number of application ideas, e.g. in the fields of health, knowledge and entertainment. Health applications include the monitoring of ill or high-risk persons, people exposed to extreme conditions or people doing sports. This also applies to therapy and improvement of physical abilities. By building much of what we normally interact with our clothing directly, we in some sense become smart people with the potential to interact with external processes in a much more natural way exploring the concept of these For-in- future use technologies, the concept of smart clothing evolves. Although the proposed technologies will replace the environmental technology but the goal is to work in harmony with some remaining degree of environmental technology. As advancements in the field of microelectronics continue, more and more computing devices will become portable and wearer-friendly. Thus we have created a unique mix of electronic and textile technology to produce an entirely new clothing concept Powered Clothing.
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