i
DEVELOPMENT OF FIBRE OPTIC ROUGHNESS MEASURING
SYSTEM USING TIME OF FLIGHT METHOD (TOF)
RAMANESHWARAN A/L BASKARAN
This Report Is Submitted In Partial Fulfillment Of Requirements For The
Bachelor Degree Of Electronic Engineering (Telecommunication)
Fakulti Kejuruteraan Elektronik dan Kejuruteraan Komputer
Universiti Teknikal Malaysia Melaka
May 2011
ii
UNIVERSTI TEKNIKAL MALAYSIA MELAKA
FAKULTI KEJURUTERAAN ELEKTRONIK DAN KEJURUTERAAN KOMPUTER
BORANG PENGESAHAN STATUS LAPORAN
PROJEK SARJANA MUDA II
Tajuk Projek : DEVELOPMENT OF FIBRE OPTIC ROUGHNESS MEASURING
SYSTEM USING TIME OF FLIGHT METHOD (TOF)
Sesi Pengajian :
Saya RAMANESHWARAN A/L BASKARAN (HURUF BESAR) mengaku membenarkan Laporan Projek Sarjana Muda ini disimpan di Perpustakaan dengan syarat-syarat kegunaan seperti berikut:
1. Laporan adalah hakmilik Universiti Teknikal Malaysia Melaka.
2. Perpustakaan dibenarkan membuat salinan untuk tujuan pengajian sahaja.
3. Perpustakaan dibenarkan membuat salinan laporan ini sebagai bahan pertukaran antara institusi
pengajian tinggi.
4. Sila tandakan ( √ ) :
SULIT*
*(Mengandungi maklumat yang berdarjah keselamatan atau
kepentingan Malaysia seperti yang termaktub di dalam AKTA
RAHSIA RASMI 1972)
TERHAD**
**(Mengandungi maklumat terhad yang telah ditentukan oleh
organisasi/badan di mana penyelidikan dijalankan)
TIDAK TERHAD
Disahkan oleh:
__________________________ ___________________________________
(TANDATANGAN PENULIS) (COP DAN TANDATANGAN PENYELIA)
iii
I hereby declare that I have read this thesis RAMANESHWARAN S/O
BASKARAN and found it is satisfactory and can be accepted
Signature :…………………………………….
Name of Supervisor :……………………………………
Date :……………………………………
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Hereby the author declares that this project entitled Development of Fibre Optic
Roughness Measuring System Using Time Of Flight Method (TOF) is the
result of my own work except for works that have been cited clearly
in reference.
Signature : …………………………………………
Name Of Author :…………………………………………..
Date :………………………………………….
v
ACKNOWLEDGEMENT
The road leading to degree was told to be long journey of perseverance and
indeed it was. I was fortunate in obtaining divine grace in enduring the path full of trial
and tribulations in the labor of studies for the past 4 years. Many individuals deserve
warm gratitude for making this thesis a reality.
It has been a great privilege to be a graduate student in the Faculty of electronics
engineering and computer engineering at the Telecommunication Department of
University Teknikal Malaysia Melaka. My experience here is full of opportunities to
learn from faculties and lecturers who are experts in the field. In addition to that, parents
and friends also have been a significant part of my life. Therefore, I would like to take
this opportunity to express my sincere gratitude to those people who are particularly
instrumental to my experience at UTEM.
First and foremost, I would like to thank my supervisor, ENGR. Zulkifli Shariff
for his invaluable guidance throughout this project in every elements and scopes of this
project. Secondly, my sincere thanks and appreciation to Pn. Norlezah Binti Hashim,
who has put a lot effort to correct and guide my circuit design and completion of the
task.
I am indebted to Mr. Shahrul, who is a R&D manager of Significant
Technologies and Mr.Hafiz assistant of Mr.Shahrul. His professionalism and great
technical advice as well as enthusiastic technical inputs have inspired me to
continuously challenge myself to reach new levels. I feel very fortunate to know him
through my supervisor under the collaboration of this project with Significant
Technologies. His wealth of knowledge in the Fibre Optics, circuit design and
programming has assisted me in identifying the problem of the project and completion
of the project. I look up to him as an excellent research advisor and would like to
express my utmost gratitude.
My acknowledgements would not be complete without expressing my gratitude
to my parents Mr & Mrs Baskaran Kalaivani for their unconditional love, support and
care throughout my studies. Their love and overwhelming support in the face of any
obstacles or adversity I faced was not only instrumental but essential in completion of
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this thesis. I would not be where I am today without their contributions and foundations
that they have provided throughout the years.
Not to forget UTEM lab technicians who helped me in dealing with lab facilities.
My heartfelt appreciation goes to all individuals who have directly and indirectly offered
help, support and suggestions in completing this project.
Last but not least, I would like express my special gratitude towards God. I feel
very fortunate to be blessed by His endless love ever. He is the true shepherd of my life.
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ABSTRACT
This project is mainly about the development of Fibre Optics Roughness
Measuring System using Time of Flight Method. This project is implemented by
construction of hardware design and software programming. The components that
involves in the construction of the circuit are PIC24FJ128GA006 microcontroller,
optical switch, circulator, laser diode, pin detector and transimpedance amplifier. The
heart of the surface roughness measuring system is the PIC24, 16-bit microcontroller
whereby it works in a very high speed in order to capture the transmitted and
received signal in light medium. The analog signal will be transmitted by the optical
switch in to the microcontroller and it will be changed to digital signal before
transmission. It will goes through the laser diode and detected by the pin detector.
The digital signal is converted back to the analog signal by using the ADC read in
the microcontroller before sending the signal to transimpedance amplifier. The
output of the signal is observed by using oscilloscope and the signal is tapped at pin
6 of the transimpedance amplifier. Finally the time difference and the voltage
difference is recorded when the laser is used to measure the surface roughness. The
ALTIUM DXP software is used in order to design the circuit and for the
programming part the MPLAB IDE is used in order to generate the C programming.
The C programming code is embedded to the PIC24 by using PICKIT 2. The
medium that have been used throughout the project is Fibre Optics and the
wavelength is a non visible wavelength which is 1550nm. The main advantage of
this project is the usage of the single mode fibre transmission. The advantage of this
transmission is, it can measure for a long distance and it minimizes the loss along the
signal transmission and this helps in producing a reliable signal when a surface
roughness is measured.
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ABSTRAK
Projek in adalah mengenai penghasilan sebuah system mengunakan
jangkaian jalur optik untuk mengukur kekasaran sesuatu permukaan. Teknik yang
ditekankan dalam projek in adalah teknik perbezaan masa antara masa maklumat
dihantar dengan maklumat diterima. Projek in mengandungi pengimplimentasian
hardware design dan programming. Komponen utama yang digunakan dalam projek
in adalah PIC24FJ128GA006 microcontroller, suis optik, circulator, diod laser,
pengesan optic dan amplifier transimpedansi. PIC24 bertindak sebagai komponen
utama dalam sistem ini kerana ia berfungsi dengan kelajuan yang tinggi untuk
mengesan cahaya daripada jalur optik ini dan pemindahan maklumat ke seluruh
sistem perlu dilakukan dengan cepat untuk memperoleh maklumat yang tepat. Cara
litar in berfungsi adalah bermula dengan penjanaan signal dari suis optic dan
maklumat dari suis optic in akan ditukarkan kepada signal digital oleh PIC24
microcontroller. Setelah proses penukaran tamat, signal itu akan dihantar ke diod
laser dan dikesan oleh pengesan optik. Maklumat akan dihantar semula ke PIC24
mikrocontroller untuk menukarkan maklumat kepada analog signal. Setelah proses in
selesai signal itu akan dihantar ke ampflier transimpedansi untuk diamplifikan dan
signal ini dapat diukur dengan mengunakan oscilloscope. Perbezaan masa dan voltan
yang diperoleh daripada oscilloscope semasa mengukur kekasaran sesuatu objek
direkodkan. Perisian yang digunakan untuk melakar litar in adalah ALTIUM DXP
dan programming dilakukan dengan menggunakan perisian MPLAB IDE. Medium
yang digunakan dalam projek in adalah rangkaian jalur optic dengan panjang
gelombang 1550nm. Keuntungan projek ini adalah penghantaran maklumat dengan
menggunakan jalur optic serat tunggal iaitu “single mode fibre”. Penggunaan jalur
optik ini membolehkan maklumat diukur pada jarak yang jauh dan meminimumkan
kehilangan maklumat yang banyak dalam seluruh proses penghantaran maklumat ini
dan ia juga membantu untuk pemerolehan maklumat yang tepat apabila kekasaran
sesuatu objek diukur.
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CONTENTS
Pages
PROJECT TITLE
DECLARATION
ACKNOWLEDGEMENT
i
iii
v
ABSTRACT vii
ABSTRAK viii
CONTENTS ix
LIST OF FIGURES xiv
LIST OF TABLE xvi
CHAPTER 1 INTRODUCTION
1.1 History of Fiber Optic……………………………….. 1
1.2 Overview..………………………………….……. 2
1.3 Objective of The Project………………….…….…… 3
1.4 Scope of The Project………………………………… 5
1.5 Research Methods…………………………………… 6
1.5.1 Literature Review and Study…………………. 7
1.5.2 Circuit Fabrication and Testing… 7
1.5.3 Complete Design and Test………………. 8
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CHAPTER 2 LITERATURE REVIEW
2.1 Roughness of surfaces………………………………. 9
2.2 Techniques and Measurement Methods of surface
roughness…………………………………………..
10
2.2.1 Profilometry………………........................... 12
2.2.2 Digital Photogrammetry……………………..
2.2.3 Laser………………………………………….
14
14
2.3 Researches done with Time Of Flight Method……… 17
2.4 Time Of Flight (TOF) Method In This Project……… 18
2.5 Advantages Of Time(TOF) Of Flight In This Project.. 19
CHAPTER 3 METHODOLOGY
3.1 Optical Fibre………………………………………….
3.1.1 Optical Fibre Constructions………………….
3.1.2 Types Of Optical Fibre……………………….
3.1.3 Advantage Of Optical Fibre …………………
3.1.4 Disadvantage Of Optical Fibre………………
3.1.5 General Uses Of Optical Fibre………………
21
21 25 27 28 29
3.2 Optical Fibres Used In The Project………………… 31
3.2.1 Laser Diode…………………………………. 31
3.2.2 Pin Detector…………………………………. 32
3.2.3 Stripping and Splicing Optical Fibre………… 32
3.2.4 Testing Power Of the Optical Fibre…………. 33
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3.3 Components Used In The Project………………….. 34
3.3.1 Optical Switch……………………………….. 34
3.3.2 Circulator…………………………………….. 35
3.3.3 PIC Microcontroller…………………………..
3.3.4 Transimpedance Amplifier…………………..
3.3.5 Voltage Regulator……………………………
3.3.6 Capacitors and Resistors…………………….
3.3.7 EEPROM 25LC256…………………………
36
37 38 38 39
3.4 Circuit Design……………………………………… 40
3.4.1 Schematic Design…………………………… 40
3.4.2 PCB Layout 2-D View………………………
3.4.3 PCB Layout 3-D View………………………
3.4.4 CamTastic View Of the PCB Layout………..
41
42 43
3.5 Programming………………………………………..
3.5.1 Configuration………………………………..
3.5.2 Input and Output…………………………….
3.5.3 Interrupt………………………………………
3.5.4 UART…………………………………………
3.5.5 Complete Programming………………………
3.5.6 Embedded Coding…………………………..
44
44 45 46 47 48 51
xii
CHAPTER 4 RESULTS AND DISCUSSION
4.1 Complete Transimpedance Circuit and Surface
Roughness Measuring System……………………….
52
4.2 System testing to obtain best displacement………….. 54
4.2.1 Results Obtained……………………………... 54
4.2.2 Explaination for Results Obtained…………… 56
4.2.3 Results Obtained for the Smooth Surface……
4.2.4 Explaination for Results Obtained…………...
4.2.5 System Testing With Copper Plate…………...
4.2.5.1 Steps Taken…………………………….
4.2.5.2 Results Obtained………………………
4.2.5.3 Explaination For Results Obtained……
4.2.6 System Testing With Plastic…………………
4.2.6.1 Steps Taken……………………………
4.2.6.2 Results Obtained………………………
4.2.6.3 Explaination For Results Obtained……
58
59
60 60 60 62 66 66 66 68
4.3 Overall Discussion……………...................................
72
CHAPTER 5 CONCLUSION AND SUGGESTION
5.1 Project Overall View………………………………… 73
5.2 Future Prospect of The Project………………………. 74
5.3 Suggestions…………………………………………... 75
xiii
REFERENCE
76
APPENDIX A
APPENDIX B
APPENDIX C
APPENDIX D
APPENDIX E
xiv
Figure 1.1 Figure 2.1 Figure 2.2 Figure 2.3 Figure 3.1 Figure 3.2 Figure 3.3 Figure 3.4 Figure 3.5 Figure 3.6 Figure 3.7 Figure 3.9 Figure3.10 Figure3.11 Figure3.12 Figure3.13 Figure3.14 Figure3.15 Figure3.16 Figure3.17 Figure3.18 Figure3.19 Figure 4.1
LIST OF FIGURES
Overall Flow Of the Project………………………………..
Brown & Sharpe Surfcom unit stylus equipment device….. Measurement techniques and isometric topographical perspectives of The used specimen………………………... Block diagram and the process flow of the method used in the Project…………………………………………………. Flow Chart Of Overall Methodology……………………… Construction of a typical fiber optic………………………. Optical Cable Construction……………………………….. Single mode, Step-index multimode, Graded-index multimode…………………………………………………. Laser Diode ( FP Laser Diode series)…………………… Coaxial Pin Detector (GPDP-2020XX Series)…………… Optical Fusion Spilicer…………………………………….. Optical Power Meter………………………………………. Optical Switch……………………………………………... Circulator…………………………………………………... PIC24FJ128GA006 Microcontroller………………………. OPA 380 (Transimpedance Amplifier)……………………. L7805CV (Voltage Regulator)……………………………. EEPROM (25LC256)…………………………………….. Schematic Diagram Of the Transimpedance Circuit……… 2-D view of the PCB layout………………………………. 3-D view of PCB layout…………………………………… CamTastic view of the PCB layout………………………... Complete Surface Roughness Measuring System………….
Pages
6
11 16 19 20 22 23 26 31 32 33 33 34 35 36 37 38 39 40 41 42 43 53
xv
Figure 4.2 Figure 4.3 Figure 4.4 Figure 4.5 Figure 4.6 Figure 4.7 Figure 4.8 Figure 4.9 Figure4.10 Figure4.11 Figure4.12
Complete system with Oscilloscope Measurement………... Graph Average Output Voltage versus Thickness /
Displacement (mm)………………………………………...
Average Output Voltages on smooth surface………………
Average Output voltage,V on smooth areas of copper plate
Average output voltage, V on rough surface of copper……
Signal Shown for Smooth Surface Of Copper Plate……….
Signal Shown For Rough Surface Of Copper Plate………..
Average Output voltage, V on smooth surface of plastic….
Average Output voltage, V on rough surface of plastic……
Signal shown for Smooth Surface Of Plastic………………
Signal shown for Rough Surface Of Plastic………………..
53 57 59 62 63 64 64 68 69 70 70
xvi
LIST OF TABLES
Pages
Table 2.1 Comparison of contact and non-contact profilometry
surface roughness…………………………………………
13
Table 2.2 Comparison of techniques used in surface roughness
measurement………………………………………………
15
Table 4.1 The displacements versus average value of output voltage 54
Table 4.2 Output voltage at different places on the smooth surface of
the stationary steel…………………………………………
58
Table 4.3 Output voltage at different places on the smooth surface of
the copper plate…………………………………………..
61
Table 4.4 Output voltage at different places on the rough surface of
the copper plate…………………………………………..
61
Table 4.5 Output voltage at different places on the smooth surface of
the plastic………………………………………………….
67
Table 4.6 Output voltage at different places on the rough surface of
the plastic…………………………………………………
67
1
CHAPTER 1 INTRODUCTION 1.1 History of fibre optic
The important step in the establishment of the industry of fibre optics
was the development of laser technology. Laser diode (LD) and light emitting
diode (LED) had the potential to generate large amounts of light in a spot tiny
enough to be useful for fibre optics. The idea of using lasers was popularized by
Gordon Gould in 1957 and later was supported by Charles Townes and Arthur
Schawlow from Bell Laboratories. In 1966, Charles Kao and Charles Hockham, from
Standard Telecommunication Laboratory, England published a paper proposing that
optical fibre can be a suitable transmission medium if its attenuation could be kept
under 20 decibels per kilometer (dB/km). With a loss of only 20dB/km, 99% of the
light would be lost over just only 3,300 feet (David, 2002) [1].
In 1970, glass researchers; Drs. Robert Maurer, Donald Keck, and Peter
Schultz from Corning succeeded in developing a purest glass fibre. This fibre
exhibited attenuation at less than 20dB/km, which is the threshold for making fibre
optics a viable technology. This can be summarized that the optical power that
reached the receiver is only 1/100th of the one transmitted (David, 2002) [1]. The
biggest challenge remaining for fibre optics is economic. Today telephone and cable
2
television companies can cost-justify installing fibre links to remote sites serving tens
to a few hundreds of customers. However, terminal equipment remains too expensive
to justify installing fibre all the way to homes, at least for present services. Instead,
cable and phone companies run twisted wire pairs or coaxial cables from optical
network units to individual homes. Time will see how long that lasts. Fibre have
many uses in remote sensing. In some applications, the sensor acts as the optical
fibre. In some other applications a non-fibre optic sensor is connected with fibre to a
measurement system. The main advantage of fibre is because of its small size or the
fact that nonelectrical power is needed at the remote location or because many
sensors can be multiplexed along the length of the fibre by using different
wavelengths of light for each sensor[2].
1.2 Overview A fibre optic sensor system is developed to probe the surface texture of
corroded metals. The present work is based on the principle of Time of Flight(TOF)
method in order to measure the surface roughness. A pulse is transmitted and the
time difference for the light takes to travel to a target and back is measured with a
single roundtrip delay. The time delay is indirectly measured by comparing the signal
from the laser with the delayed signal returning from the target. The fibre optic
sensor system can be used to estimate the surface roughness of the measured
material.
The surface roughness of an object can be measured either mechanically or
optically. Mechanical devices based on the profilometer and digital photogrammetry
principle are expensive, can be unreliable in certain applications, and require
physical contact with the surface of interest. The surface damage that may result can
3
corrupt the measurement data. Noncontact optical techniques with implementation of
the TOF method eliminate the problems of surface damage and inaccurate data, but
they require very precise optical elements that must be realigned continually (Sensors
Magazine Online - April 1999) [3]. However, this method is far cheaper compared to
the some other methods. Therefore through this project, Time of Flight(TOF) method
of measuring roughness of a surface can be develope and this can be applied in our
industry as it might reduce the production cost.
1.3 Objective of the project There are few objectives that are outlined for the purpose of this
project. They are as follows :
i. The main objective is this final year project (FYP) is a must in order
to fulfill the four years of engineering course or degree in UTEM. FYP is
one of the main requirements in achieving degree in UTEM. A student is
considered capable and qualified as an engineer after finishing his FYP
under a qualified lecturer or others who have the same status as lecturers. It
helps the students to expose themselves in organizing a project and to
measure their ability in finding and selecting information, their
communication skills, time management and self-management.
ii. The intrinsic objective of this FYP is to develop a fibre optic
roughness measuring system by using Time Of Flight(TOF) method. This
development consists of designing the transimpedance circuit, fabricating the
hardware, interfacing of software, transmitting the pulse at different pulse
4
width, measuring the roughness of surfaces and finally evaluating the results
to obtain the roughness of the surfaces.
iii. The objective of the present study is to measure the surface
roughness and surface profile of the engineering materials by an optical
system using the Time of Flight technique. Other than that, it is concerned in
studying the history and theory of fibre optics and designing a system to
measure roughness of given surfaces using fibre optics. The literature review
of this project enlightens me with new methods of measuring surface
roughness including the method used in this project, especially in
transmitting and receiving the pulse using different pulse width from
surfaces to get measurements of roughness.
iv. Last but not least, through this project I manage to improve my
skills in many ways. My planning skills, analytical skills and calculative
skills improved throughout this project. I got to know how great fibre optic
plays its role in our modern society to gain more knowledgeable and useful
tools for the customers. It really gives a big satisfaction in knowing and
working with fibre optics and its applications. FYP also helps students to be
independent while doing their project and this can help students to get a pre-
working experience.
5
1.4 Scope of the project
Firstly, there are many applications using fibre optic, which is implemented
in industry, medical, security, telecommunication, submarine, laboratory fields,
decorative purposes and others. In this project, fibre optics is used as transmitting
and receiving light using different pulse width and the resolution of the pulse width
to and from targeted surface to measure the roughness of the surface. The scope of
the project is to measure the roughness of surfaces from the smooth ones until the
rough ones, which can be proved that the idea is applicable, based on the
experimental results and the resolutions measured. The scope of the project does not
include the thickness and analysis of the surface roughness as this involves another
method, which is not done through this project. This is because it requires other
additional facilities and applications.
6
1.5 Research methods
The development of a fiber optic in measuring the system roughness involves a lot of
research, which was done step by step. Interferences between one step to another do
happen at times but this was unproblematic to handle when there is a clear view of
overall flow of the project. The steps involved are elaborated briefly and shown in
figure.
Briefing & Discussion with lecturer
Survey & Literature Review
Design of transimpedance circuit
Circuit testing & Analysis
Implementation circuit with software
Interfacing software system & circuit for compatible
Testing & reading
Data collection & analysis
Figure 1.1: Overall flow of the project
Proposal
Progress Report
Final report
Understanding project
Design
Fabrication & Testing
7
1.5.1 Literature Review and Study
First of all, understanding the title chosen is very important in order to get a
better view of the project and its scope. For this purpose, a lot of researches have
been carried out through journals, Internet, and books from various sources. Related
topics regarding the project were found to get a better understanding of the project as
well as the flow of it. The conducted research was about history, constructions, types,
advantages, disadvantages, propagation, applications in fibre optics and fibre optics
as sensors. Overall, this step was a stepping-stone in understanding the general view
of the project and a good start to begin the project.
1.5.2 Circuit Fabrication and Testing
The following step after designing of the circuits is the fabrication. These
circuits consist of two parts: transmitter and receiver. These circuits are combined
together as transimpedance circuit . Later once the circuits are giving satisfactory
results, the hardware is interfaced with the software and testing is continued with the
full connection of the system. The analysis for this fabricated circuit will be about the
roughness and measuring the surface roughness using different pulse width and
measure the resolution obtained. It also shows the differences between the theory and
the practical results of the fabricated circuit and also problems while doing the
testing. Graphical analysis is being used most in evaluating the results.
8
1.5.3 Complete Design and Test
Finally when all the testing is over with simulation result and circuit design,
the schematic is implemented on Printed Circuit Board (PCB). ALTIUM DXP
Software is used in order to draw the layout and the components are being soldered
to the board. Again the testing is done to confirm the capability of the fibre optic
system and its accuracy. Graphical method was used in determining the precision of
the results.
