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1. A Seminar Report
On
Arm-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

2. VAAGDEVI COLLEGE OF ENGINEERING
Bollikunta, Warangal, 506005
(Affiliated to JNTU, Hyderabad)
CERTIFICATE
This is to certify that Seminar report entitled “Arm-Band type Textile-MP3
Player with Multi-layer Planar Fashionable Circuit Board (P-FCB)
Techniques” is prepared and submitted by K.SUHAS (07641A0428), in partial
fulfillment for award of the degree of Bachelor of Technology in Electronics &
communication engineering.
Dr.D.V.KRISHNA REDDY V.RAJANNA
Head of the Department, ECE Lecturer

3. ACKNOWLEDGMENT
This Success accomplished in this Project would not be have been possible but for the
timely help and guidance by many people. We wish to express our sincere and heartfelt
gratitude to all those who have helped us in one-way or the other for completion of our
project.
We offer our sincere thanks to the Management, Director, Prof K.Kishan Rao, Principal
and Prof.CH.Sathaiah and to Dr.D.V.Krishna Reddy, Head of the Department, Dept. of
Electronics and communication engineering in providing the necessary facilities for carrying
out our project in time.
We express our deep sense of gratitude to V.Rajanna, Lecturer in ECE for giving
necessary suggestion to prepare the seminar report. We also express our sincere gratitude to
teaching and non-teaching faculty member in the Department of Computer Science for their
suggestions and taking care of all the software needs.
K.SUHAS

4. ABSTRACT
Arm-band type textile-MP3 player using direct chip integration technique into textile named
Planar Fashionable Circuit Board (P-FCB) is designed. The multi-layered improves the
integration 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 show
the possibility of using P-FCB in wearable entertainment system

5. CONTENTS Page
1. Introduction 01
2. State of the art wearable electronics 02
3. Higher integration techniques for P-FCB 04
4. Wearable user i/o interface for P-FCB 08
5. System implementation results 11
6. Conclusion 14
7. References 15

6. 1|Page
1. INTRODUCTION
The 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 and
pervasive 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 full
platform into clothes. In healthcare application, this fully integrated platform into the textile
is already introduced for continuous and wearable health monitoring system. It is shown that
the system can be fully integrated without any bulky external components so that there is no
disturbance in both person’s activity and aesthetic appearance.
However, there is no previous attempt to apply this platform to entertainment application due
to some difficult issues on system implementation. The first issue is higher integration level
requirement which results from that the entertainment system platform is more complex so
that more layers are needed than healthcare system. And the second issue is wearable user I/O
interface, 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 as
circuit board itself, and they have not been developed yet. Instead, other manufacturing
techniques are introduced for wearable entertainment systems. However, some of them use
conductive wires to interconnect external IC components, and some of them use bulky
components to implement user interface. Therefore, it is revealed that all of them do not show
the completely wearable entertainment system.
In this paper, we propose the wearable electronic system for entertainment application using
fully integration techniques into the textile. To make it possible to apply the entertainment
system rather than healthcare system, multi-layer manufacturing technique and user-friendly
I/O interface are proposed. The rest of the paper is organized as follows. In Section 2, the
state-of-the-art wearable electronics techniques named Planar-Fashionable Circuit Board (P-
FCB) will be introduced with some previous examples. Section 3 describes the proposed
higher integration techniques for P-FCB to implement the multi-layered board, and Section 4
covers the wearable user I/O interface. And the system implementation result will be
presented in Section 5. Finally, conclusions will be made in Section 6.

7. 2|Page
2. STATE-OF-THE-ART WEARABLE ELECTRONICS:
PLANAR-FASHIONABLE CIRCUIT BOARD
Planar Fashionable Circuit Board (P-FCB) is a new flexible electronics technology firstly
introduced by Hyejung Kim. It implements the circuit board on the plain fabric patch for
wearable electronics applications. Various examples of P-FCB samples are shown in Fig. 1. It
can support very soft and flexible feelings just same as clothes. Previous P-FCB systems for
continuous healthcare application systems are already proposed and implemented.
Fig. 1. Various P-FCB Patterning and Integration
First, the circuit board is silkscreen printed on the fabric patch (Fig. 2-1). And the bare IC and
ultra-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 [2] adopts the additional multi-layered
technique, not to increase the integration level of the circuit board itself, but to attach the
electrode, communication antenna, and battery. The technique will be explained more detail
in Section 3. There are also some previous researches to figure out the electrical and
mechanical characteristics, and valuable system design parameters are obtained such as
maximum power consumption, maximum current density, crosstalk between neighboring two
lines, and durability to tear out. Based on this background knowledge about Planar

8. 3|Page
Fashionable Circuit Board (P-FCB), some process improvement techniques will be proposed
and introduced in Section 3 and 4.
Fig. 2. Single-layered P-FCB system manufacturing process

9. 4|Page
3. Higher Integration Techniques for P-FCB
Since entertainment application systems are more complex than healthcare systems, multi-
layer structure is essential for higher integration level. To maintain high wear ability and
good aesthetic appearance, the connection between two layers should be wearable and
pervasive. There are several methods to implement this connection. The possible methods are
listed as follows:
(1) Using conductive thread
(2) Using conductive tape in both-sides
(3) Using small metal connector named eyelet
(4) Using conductive adhesive
To 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 small
area 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 fabric
The first method using conductive thread is the most intuitive way but it is very hard to make
a knot in extremely small area. So it cannot achieve high integration level enough. Also, the
second method using conductive tape in both-sides is not good that much. The conductive
tape 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 the
connection 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 is
commonly used to make the decoration in clothes. To connect both sides of the fabric, two
fabrics are aligned and stacked together at first. And the sharp side of the eyelet is passed
through patterns on two fabrics. In this step, the conductive pattern on fabric #1 is connected
with eyelet. But the pattern on fabric #2 is still floated.

10. 5|Page
Fig. 4. Implementation of multi-layer connection using eyelet
Finally, the sharp side of the eyelet is hammered to connect the eyelet with conductive
patterns on fabric #2. Fig. 4 shows the implementation result of two layer connection using
eyelet. Although it has a small resistance below a few ohms and the size can be as small as
2mm2, this method has a huge drawback. It can only connect the back-to-back side of two
fabrics. Therefore, the connection between more than three layers cannot be implemented in
the same location. It degrades the integration level. Also, the eyelet is not the perfect planar
structure 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 is
proposed. Fig. 5 shows the multi-layer connection process using conductive adhesive. It
consists of mainly 2 steps. At first, via is formed at the back-side of upper layer pattern
wherever 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 is
pasted on the backside via pattern of the fabric #1. Then the upper and lower layer fabrics #1
and #2 are aligned and pressed to be attached to each other (Fig. 5-2). Since this method is
applied on the hidden side of both fabric layers, it does not affect the aesthetic appearance at
all. Also its thickness is much less than the fabric thickness and almost the same as that of
silkscreen pattern, so the planar structure of the board is still maintained resulting in high
wear ability.

11. 6|Page
Fig. 5. Multi-layer connection process using conductive adhesive
The other huge advantage of this method rather than the third method with eyelet is the
extendibility to more than three layers. Since this method uses opposite-side layers of each
fabric, the maximum number of layer which can be stacked is not limited. It means that the
integration level of P-FCB is unlimited. Therefore, much more complex system can also be
implemented 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 photo
of 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 silver
parts are silkscreen printed patterns, and the red part is the yarn in the fabric. The via
formation place is highlighted with dashed line box. It is shown that silkscreen patterns are
passed through the fabric so that the both sides of one fabric are connected to each other.

12. 7|Page
Fig. 6. SEM photo of the proposed via structure
The resistance measurement result of the proposed via and conductive adhesive is shown in
Fig. 7. To get an average value, as many as 100 connections are formed and measured. The
resistances of the proposed via and conductive adhesive are measured as 0.24ohm and
0.34ohm, respectively. Since the resistance of the silkscreen printed pattern in P-FCB is
0.05ohm/mm and the wire length is normally over 10 times than wire width [8], the proposed
via and conductive adhesive resistance does not degrade the system performance. And to
lower the resistance value of the proposed via, we can increase the via size over 1mm x 2mm
of 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 last
method using conductive adhesive is considered as the best way to form a multi-layer
connection. Therefore, the further system implementation uses conductive adhesive method
for multi-layer connection.

13. 8|Page
4. WEARABLE USER I/O INTERFACE FOR P-FCB
Entertainment 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 MP3
player system. Therefore, user I/O interface is very important for entertainment system. Until
now, these I/O interfaces were implemented with external components which are bulky and
not wearable. They cannot be fully integrated into clothes, so user feels uncomfortable due to
them. Moreover, they are connected with wires like conductive threads, which increase the
manufacturing cost than printing process of P-FCB. Therefore, the process improvement for
I/O interface is necessary. In this Section, the new wearable and pervasive user I/O interface
is 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 is
processed 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 the
fabric itself has small invisible holes, a via can connect the both sides of one fabric
physically. After that, fabric #3 is put between fabric #1 and #2. There is no connection
between fabric #1 and #2 if there is no external pressure. On the other hand, there is physical
connection 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 method
To verify the operation of wearable user I/O interface, simple LED lightening system is
implemented as shown in Fig. 9. Each LED is turned on when the corresponding switches are
pressed. Patterns on fabric are made from gold foil for aesthetic. Gold foil patterns do the
same function as silver paste in screen-printing method. One side of LED array is connected
to the switch with conductive adhesive and conductive yarn. The other side of LED array is
connected to battery. Since this proposed I/O interface consists of only fabric, it shows much
better wear ability compared to previous I/O interfaces.

14. 9|Page
Fig. 9. Measurement result of wearable User Input Interface
The structure of wearable user output interface is shown in Fig. 10. Each screen-printed
column and row lines are located with uniform space. Single layer screen pattern is not
connected with back side of layer. So each row and column can be existed in the same layer
with no connection. After that, LED array is located properly and connected with row and
column lines using conductive adhesive.
Fig. 10. Wearable User Output Interface process using multi layer connection method
Fig. 11 shows the system integration of the proposed input and output devices. LED array is
controlled by IC chip. Once the switch is pressed, the number displayed in LED array is
increased.

15. 10 | P a g e
Fig. 11. Measurement result of wearable User Output Interface

16. 11 | P a g e
5. SYSTEM IMPLEMENTATION RESULTS
In this section, MP3 player system is implemented and demonstrated to show the
possibility of using P-FCB in wearable entertainment system.
The manufacturing process of MP3 player system using P-FCB is shown in Fig. 12. At
first, two layers are screen printed with circuit pattern on two fabric patches (Fig 11-1). Silver
paste is used as material for screen printing. These circuit patterns are drawn considering the
connection of IC chip, memory card, and other devices. Due to the complex connection
between 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-layer
P-FCB process, it is very important to locate all ICs in the upper-most layer. This is because
if the ICs are placed between two fabric layers, the inter-layer connection becomes unstable
due to IC’s thickness. So it is recommended that all ICs are in the upper-most layer, and there
are only connecting patterns in lower layers. Since the line width and spacing of P-FCB are
limited as 0.2mm and 0.1mm, respectively, as described in [8], the patterns should be drawn
within these limitations. To optimize the system size and stability of pattern drawing, both the
line width and spacing are chosen as 0.5mm in this work.
Fig. 12.Arm-band type textile MP3 player system process

17. 12 | P a g e
At second layer, power and ground lines are connected. In entertainment system, power
consumption is quite large so the power line should support large current flow with no heat
dissipation. Therefore, power and ground lines are drawn as thick as 0.8cm in this work to
make the line resistance becomes smaller than that of normal connecting pattern. The size of
the contact between two fabric layers is chosen to be 2mm x 2mm. Since the conductive
adhesive can be spread out during the manufacturing process so that closer lines become
shorted to each other, 2mm x 2mm size is adopted for stable manufacturing process although
the 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 each
other successfully, IC chips and several peripherals are bonded on the fabric. Depending on
the types of IC and peripherals, the bonding methods can be differed [8]. For the
microcontroller (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-attaching
method using conductive epoxy, which is the exactly same method as conventional bonding
process of surface mounted device type (SMD) on PCB. For Micro SD card, the socket is
used for easy addition and removal of the songs, because users want to change the music files
very 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 to
protect connections between the device and patterns on fabric (Fig. 12-3). The final system
can be directly integrated into clothes as shown in Fig. 12-4 and Fig. 12-5 shows the
completed arm-band type textile MP3-player.
By using this manufacturing process, MP3 player system is implemented and placed on
user’s arm as shown in Fig. 13. The proposed MP3 player system made by P-FCB technique
is attached at back side of fabric ornament of the forearm band. User I/O interface which was
explained 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 not
feel any disturbance during activity. Also, the aesthetic appearance is still maintained as
good. So the proposed MP3 player system is expected to be used in daily activity such as
exercises. This proposed MP3 player system using P-FCB works well as shown in Fig. 14.

18. 13 | P a g e
Fig. 13. Implementation of MP3 player system.
Fig. 14. Measurement of MP3 player system.

19. 14 | P a g e
6. CONCLUSION
In this work, we propose and implement the wearable entertainment systems by using Planar
Fashionable Circuit Board (P-FCB) Technology. Thanks to the proposed multi-layered board
manufacturing technique with conductive adhesive, we can increase the integration level of
P-FCB. Also, wearable user input-output interface makes people can control the P-FCB
system freely without any disturbance. With these two techniques, arm-band type textile MP3
player system is developed and demonstrated to verify the possibility of P-FCB in wearable
entertainment system.

20. 15 | P a g e
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layered Planar Fashionable Circuit Board,” IEEE International Symposium on
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