A Seminar Report OnArm-Band type Textile-MP3 Player with Multi-layer Planar Fashionable Circuit Board (P-FCB) Techniques A Seminar report submitted in partial fulfillment for the awarded of degree BACHELOR OF TECHNOLOGY IN Electronics and Communication Engineering By K.SUHAS (07641A0428) Under the guidance of V.RAJANNA (Lecturer) Department of Electronics and Communication engineering VAAGDEVI COLLEGE OF ENGINEERING (Affiliated to JNTU, Hyderabad) Bollikunta, Warangal, 506005 2010-2011
VAAGDEVI COLLEGE OF ENGINEERING Bollikunta, Warangal, 506005 (Affiliated to JNTU, Hyderabad) CERTIFICATEThis is to certify that Seminar report entitled “Arm-Band type Textile-MP3Player with Multi-layer Planar Fashionable Circuit Board (P-FCB)Techniques” is prepared and submitted by K.SUHAS (07641A0428), in partialfulfillment for award of the degree of Bachelor of Technology in Electronics &communication engineering.Dr.D.V.KRISHNA REDDY V.RAJANNAHead of the Department, ECE Lecturer
ACKNOWLEDGMENT This Success accomplished in this Project would not be have been possible but for thetimely help and guidance by many people. We wish to express our sincere and heartfeltgratitude to all those who have helped us in one-way or the other for completion of ourproject. We offer our sincere thanks to the Management, Director, Prof K.Kishan Rao, Principaland Prof.CH.Sathaiah and to Dr.D.V.Krishna Reddy, Head of the Department, Dept. ofElectronics and communication engineering in providing the necessary facilities for carryingout our project in time. We express our deep sense of gratitude to V.Rajanna, Lecturer in ECE for givingnecessary suggestion to prepare the seminar report. We also express our sincere gratitude toteaching and non-teaching faculty member in the Department of Computer Science for theirsuggestions and taking care of all the software needs. K.SUHAS
ABSTRACTArm-band type textile-MP3 player using direct chip integration technique into textile namedPlanar Fashionable Circuit Board (P-FCB) is designed. The multi-layered improves theintegration level so that more complex system can be implemented using P-FCB. Also,wearable user input-output people control the system freely without any disturbance.Finally, Arm-band type textile-MP3 player system is developed and demonstrated to showthe possibility of using P-FCB in wearable entertainment system
CONTENTS Page1. Introduction 012. State of the art wearable electronics 023. Higher integration techniques for P-FCB 044. Wearable user i/o interface for P-FCB 085. System implementation results 116. Conclusion 147. References 15
1|Page 1. INTRODUCTIONThe greater demand for portable device shows up recently in the areas of medical, healthcare,and entertainment. Since these systems are used in person’s everyday life, more wearable andpervasive platforms are required not to obstruct his/her activity and aesthetic appearance.The best way for maximizing both wear ability and aesthetic sense is integration of the fullplatform into clothes. In healthcare application, this fully integrated platform into the textileis already introduced for continuous and wearable health monitoring system. It is shown thatthe system can be fully integrated without any bulky external components so that there is nodisturbance in both person’s activity and aesthetic appearance.However, there is no previous attempt to apply this platform to entertainment application dueto some difficult issues on system implementation. The first issue is higher integration levelrequirement which results from that the entertainment system platform is more complex sothat more layers are needed than healthcare system. And the second issue is wearable user I/Ointerface, it is because people use I/O interface more frequently in entertainment system.Both the multi-layer connection and user I/O interface should offer the enough flexibility ascircuit board itself, and they have not been developed yet. Instead, other manufacturingtechniques are introduced for wearable entertainment systems. However, some of them useconductive wires to interconnect external IC components, and some of them use bulkycomponents to implement user interface. Therefore, it is revealed that all of them do not showthe completely wearable entertainment system.In this paper, we propose the wearable electronic system for entertainment application usingfully integration techniques into the textile. To make it possible to apply the entertainmentsystem rather than healthcare system, multi-layer manufacturing technique and user-friendlyI/O interface are proposed. The rest of the paper is organized as follows. In Section 2, thestate-of-the-art wearable electronics techniques named Planar-Fashionable Circuit Board (P-FCB) will be introduced with some previous examples. Section 3 describes the proposedhigher integration techniques for P-FCB to implement the multi-layered board, and Section 4covers the wearable user I/O interface. And the system implementation result will bepresented in Section 5. Finally, conclusions will be made in Section 6.
2|Page 2. STATE-OF-THE-ART WEARABLE ELECTRONICS: PLANAR-FASHIONABLE CIRCUIT BOARDPlanar Fashionable Circuit Board (P-FCB) is a new flexible electronics technology firstlyintroduced by Hyejung Kim. It implements the circuit board on the plain fabric patch forwearable electronics applications. Various examples of P-FCB samples are shown in Fig. 1. Itcan support very soft and flexible feelings just same as clothes. Previous P-FCB systems forcontinuous healthcare application systems are already proposed and implemented. Fig. 1. Various P-FCB Patterning and IntegrationFirst, the circuit board is silkscreen printed on the fabric patch (Fig. 2-1). And the bare IC andultra-thin metal plates are attached on the fabric to connect IC and circuit board (Fig. 2-2).After that, they are wire-bonded to each other (Fig. 2-3). Finally, the IC is molded with non-conductive epoxy (Fig. 2-4). Only the system in  adopts the additional multi-layeredtechnique, not to increase the integration level of the circuit board itself, but to attach theelectrode, communication antenna, and battery. The technique will be explained more detailin Section 3. There are also some previous researches to figure out the electrical andmechanical characteristics, and valuable system design parameters are obtained such asmaximum power consumption, maximum current density, crosstalk between neighboring twolines, and durability to tear out. Based on this background knowledge about Planar
3|PageFashionable Circuit Board (P-FCB), some process improvement techniques will be proposedand introduced in Section 3 and 4. Fig. 2. Single-layered P-FCB system manufacturing process
4|Page 3. Higher Integration Techniques for P-FCBSince entertainment application systems are more complex than healthcare systems, multi-layer structure is essential for higher integration level. To maintain high wear ability andgood aesthetic appearance, the connection between two layers should be wearable andpervasive. There are several methods to implement this connection. The possible methods arelisted as follows: (1) Using conductive thread (2) Using conductive tape in both-sides (3) Using small metal connector named eyelet (4) Using conductive adhesiveTo find the best way, above 4 methods are all tested with drape characteristic of the fabric.The best solution for multi-layer circuit board should not only have low resistance and smallarea but also maintain the drape characteristic of the fabric itself. To check the drape-ability,the simple device is newly developed as shown in Fig. 3. Fig. 3. Drape characteristic test of fabricThe first method using conductive thread is the most intuitive way but it is very hard to makea knot in extremely small area. So it cannot achieve high integration level enough. Also, thesecond method using conductive tape in both-sides is not good that much. The conductivetape should be cut and attached by hand, and the tape area is also limited by that. Moreover,the adhesive material on the tape degrades the electrical conductivity of the tape. So theconnection between two layers has large resistance above a few hundred ohms.The third method is to use the small metal ring named eyelet which is shown in Fig. 4. It iscommonly used to make the decoration in clothes. To connect both sides of the fabric, twofabrics are aligned and stacked together at first. And the sharp side of the eyelet is passedthrough patterns on two fabrics. In this step, the conductive pattern on fabric #1 is connectedwith eyelet. But the pattern on fabric #2 is still floated.
5|Page Fig. 4. Implementation of multi-layer connection using eyeletFinally, the sharp side of the eyelet is hammered to connect the eyelet with conductivepatterns on fabric #2. Fig. 4 shows the implementation result of two layer connection usingeyelet. Although it has a small resistance below a few ohms and the size can be as small as2mm2, this method has a huge drawback. It can only connect the back-to-back side of twofabrics. Therefore, the connection between more than three layers cannot be implemented inthe same location. It degrades the integration level. Also, the eyelet is not the perfect planarstructure even after hammering so that it reduces the wear ability of the P-FCB system.To eliminate these drawbacks of eyelet process, the last method using conductive adhesive isproposed. Fig. 5 shows the multi-layer connection process using conductive adhesive. Itconsists of mainly 2 steps. At first, via is formed at the back-side of upper layer patternwherever the connection is needed between two fabric layers (Fig. 5-1). To implement via,the backside of the fabric #1 is screen-printed. Since the fabric itself has small invisible holes,a via can connect the both sides of one fabric physically. After that, conductive adhesive ispasted on the backside via pattern of the fabric #1. Then the upper and lower layer fabrics #1and #2 are aligned and pressed to be attached to each other (Fig. 5-2). Since this method isapplied on the hidden side of both fabric layers, it does not affect the aesthetic appearance atall. Also its thickness is much less than the fabric thickness and almost the same as that ofsilkscreen pattern, so the planar structure of the board is still maintained resulting in highwear ability.
6|Page Fig. 5. Multi-layer connection process using conductive adhesiveThe other huge advantage of this method rather than the third method with eyelet is theextendibility to more than three layers. Since this method uses opposite-side layers of eachfabric, the maximum number of layer which can be stacked is not limited. It means that theintegration level of P-FCB is unlimited. Therefore, much more complex system can also beimplemented using P-FCB with this proposed multi-layer connection method.To verify that the proposed via structure is enough for multi-layer connection, the SEM photoof via and the resistance measurement of via is performed as shown in Fig. 6 and Fig. 7,respectively. In Fig. 6, the both sides of one fabric are partially screen-printed. The silverparts are silkscreen printed patterns, and the red part is the yarn in the fabric. The viaformation place is highlighted with dashed line box. It is shown that silkscreen patterns arepassed through the fabric so that the both sides of one fabric are connected to each other.
7|Page Fig. 6. SEM photo of the proposed via structureThe resistance measurement result of the proposed via and conductive adhesive is shown inFig. 7. To get an average value, as many as 100 connections are formed and measured. Theresistances of the proposed via and conductive adhesive are measured as 0.24ohm and0.34ohm, respectively. Since the resistance of the silkscreen printed pattern in P-FCB is0.05ohm/mm and the wire length is normally over 10 times than wire width , the proposedvia and conductive adhesive resistance does not degrade the system performance. And tolower the resistance value of the proposed via, we can increase the via size over 1mm x 2mmof the current size.With the consideration of several factors including integration level, aesthetic appearance,wear ability degradation, the resistance, and the drape maintenance of the fabric, the lastmethod using conductive adhesive is considered as the best way to form a multi-layerconnection. Therefore, the further system implementation uses conductive adhesive methodfor multi-layer connection.
8|Page 4. WEARABLE USER I/O INTERFACE FOR P-FCBEntertainment system usually requires more interaction with users than healthcare system.For example, the user can often control the volume, and add or remove the play list of MP3player system. Therefore, user I/O interface is very important for entertainment system. Untilnow, these I/O interfaces were implemented with external components which are bulky andnot wearable. They cannot be fully integrated into clothes, so user feels uncomfortable due tothem. Moreover, they are connected with wires like conductive threads, which increase themanufacturing cost than printing process of P-FCB. Therefore, the process improvement forI/O interface is necessary. In this Section, the new wearable and pervasive user I/O interfaceis proposed, which uses the previously introduced multi-layer connection method in Section3.The structure of wearable user input interface is shown in Fig. 8. The manufacturing isprocessed as follows. At first, fabric #1 and fabric #2 is screen printed with being aligned.The backside of the fabric #1 is also screen-printed. As described in Section 3, since thefabric itself has small invisible holes, a via can connect the both sides of one fabricphysically. After that, fabric #3 is put between fabric #1 and #2. There is no connectionbetween fabric #1 and #2 if there is no external pressure. On the other hand, there is physicalconnection between fabric #1 and #2 if the external pressure is applied on the fabric #1. Fig. 8. Wearable User Input Interface using multi layer connection methodTo verify the operation of wearable user I/O interface, simple LED lightening system isimplemented as shown in Fig. 9. Each LED is turned on when the corresponding switches arepressed. Patterns on fabric are made from gold foil for aesthetic. Gold foil patterns do thesame function as silver paste in screen-printing method. One side of LED array is connectedto the switch with conductive adhesive and conductive yarn. The other side of LED array isconnected to battery. Since this proposed I/O interface consists of only fabric, it shows muchbetter wear ability compared to previous I/O interfaces.
9|Page Fig. 9. Measurement result of wearable User Input InterfaceThe structure of wearable user output interface is shown in Fig. 10. Each screen-printedcolumn and row lines are located with uniform space. Single layer screen pattern is notconnected with back side of layer. So each row and column can be existed in the same layerwith no connection. After that, LED array is located properly and connected with row andcolumn lines using conductive adhesive. Fig. 10. Wearable User Output Interface process using multi layer connection methodFig. 11 shows the system integration of the proposed input and output devices. LED array iscontrolled by IC chip. Once the switch is pressed, the number displayed in LED array isincreased.
10 | P a g e Fig. 11. Measurement result of wearable User Output Interface
11 | P a g e 5. SYSTEM IMPLEMENTATION RESULTS In this section, MP3 player system is implemented and demonstrated to show thepossibility of using P-FCB in wearable entertainment system. The manufacturing process of MP3 player system using P-FCB is shown in Fig. 12. Atfirst, two layers are screen printed with circuit pattern on two fabric patches (Fig 11-1). Silverpaste is used as material for screen printing. These circuit patterns are drawn considering theconnection of IC chip, memory card, and other devices. Due to the complex connectionbetween devices, two layers of circuit board are required. At first layer, microcontroller chip,MP3 decoder chip, a SD memory socket, and an earphone socket are located. In multi-layerP-FCB process, it is very important to locate all ICs in the upper-most layer. This is becauseif the ICs are placed between two fabric layers, the inter-layer connection becomes unstabledue to IC’s thickness. So it is recommended that all ICs are in the upper-most layer, and thereare only connecting patterns in lower layers. Since the line width and spacing of P-FCB arelimited as 0.2mm and 0.1mm, respectively, as described in , the patterns should be drawnwithin these limitations. To optimize the system size and stability of pattern drawing, both theline width and spacing are chosen as 0.5mm in this work. Fig. 12.Arm-band type textile MP3 player system process
12 | P a g eAt second layer, power and ground lines are connected. In entertainment system, powerconsumption is quite large so the power line should support large current flow with no heatdissipation. Therefore, power and ground lines are drawn as thick as 0.8cm in this work tomake the line resistance becomes smaller than that of normal connecting pattern. The size ofthe contact between two fabric layers is chosen to be 2mm x 2mm. Since the conductiveadhesive can be spread out during the manufacturing process so that closer lines becomeshorted to each other, 2mm x 2mm size is adopted for stable manufacturing process althoughthe experimental result shows that smaller than 2mm x 2mm can be used. After the first step,two layers are aligned and connected (Fig 11-2). After two fabric layers are connected to eachother successfully, IC chips and several peripherals are bonded on the fabric. Depending onthe types of IC and peripherals, the bonding methods can be differed . For themicrocontroller (bare die type IC), wire-bonding method using ultra-thin gold wire is used.Or the MP3 decoder chip (Surface-mount type package IC) is bounded by die-attachingmethod using conductive epoxy, which is the exactly same method as conventional bondingprocess of surface mounted device type (SMD) on PCB. For Micro SD card, the socket isused for easy addition and removal of the songs, because users want to change the music filesvery often. This socket is SMD-type, so the bonding method is same as MP3 decoder IC.After attaching IC on fabric, each IC component is molded with non-conductive epoxy toprotect connections between the device and patterns on fabric (Fig. 12-3). The final systemcan be directly integrated into clothes as shown in Fig. 12-4 and Fig. 12-5 shows thecompleted arm-band type textile MP3-player.By using this manufacturing process, MP3 player system is implemented and placed onuser’s arm as shown in Fig. 13. The proposed MP3 player system made by P-FCB techniqueis attached at back side of fabric ornament of the forearm band. User I/O interface which wasexplained in Section 4, is integrated into this system in order to achieve high wear ability.Since both I/O interface and system itself are directly formed on the fabric, the user does notfeel any disturbance during activity. Also, the aesthetic appearance is still maintained asgood. So the proposed MP3 player system is expected to be used in daily activity such asexercises. This proposed MP3 player system using P-FCB works well as shown in Fig. 14.
13 | P a g e Fig. 13. Implementation of MP3 player system. Fig. 14. Measurement of MP3 player system.
14 | P a g e 6. CONCLUSIONIn this work, we propose and implement the wearable entertainment systems by using PlanarFashionable Circuit Board (P-FCB) Technology. Thanks to the proposed multi-layered boardmanufacturing technique with conductive adhesive, we can increase the integration level ofP-FCB. Also, wearable user input-output interface makes people can control the P-FCBsystem freely without any disturbance. With these two techniques, arm-band type textile MP3player system is developed and demonstrated to verify the possibility of P-FCB in wearableentertainment system.
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