ULTRASONIC CANE FOR THE BLIND: TRANSMITTER AND RECEIVER
MAZLIYANA BINTI AYUB
This report is submitted in partial fulfillment of the requirements for the award of
Bachelor of Electronic Engineering (Industrial Electronics) With Honours
Faculty of Electronic and Computer Engineering
Universiti Teknikal Malaysia Melaka
APRIL 2009
UNIVERSTI TEKNIKAL MALAYSIA MELAKA FAKULTI KEJURUTERAAN ELEKTRONIK DAN KEJURUTERAAN KOMPUTER
BORANG PENGESAHAN STATUS LAPORAN
PROJEK SARJANA MUDA II
Tajuk Projek : ULTRASONIC CANE FOR THE BLIND: TRANSMITTER AND RECEIVER
Sesi
Pengajian : 2008/2009
Saya MAZLIYANA BINTI AYUB 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)
Alamat Tetap: 271, Jalan Fajar, Felda Lubuk Merbau,
06710 Pendang, Kedah.
Tarikh: Tarikh: ………………………..
“I hereby declare that this report is the result of my own work except for quotes as
cited in the references.”
Signature : ………………………………..
Author : MAZLIYANA BINTI AYUB
Date : ……………………………….
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“I hereby declare that I have read this report and in my opinion this report is
sufficient in terms of the scope and quality for the award Bachelor of Electronic
Engineering (Industrial Electronic) With Honours.”
Signature :
Supervisor’s Name :
Date :
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Dedicated for my beloved father and mother…
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ACKNOWLEDGEMENT
Firstly, I would like to dedicate my highest gratitude to Allah SWT for giving
me the strength to complete this final project.
I would like to express my heartfelt gratitude to my supervisors, Pn. Siti
Khadijah binti Idris for guiding this work with utmost interest, patience, cares and
scientific rigor. I am grateful to her for setting high standards and giving me the
freedom to explore many things. Thank you for the time and experiences shared as
well as additional knowledge gained as I believe that I would not get this kind of
opportunity elsewhere.
I am thankful to my family for bearing with me during this venture and
providing the strength to persist. Finally, a special mention for my friends in the
department, whose support and suggestions went along way in making this work a
reality. Thank you.
.
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ABSTRACT
The purpose of this project is to develop the Electronic Travel Aid for the blind
people. It will involve the ultrasonic technology to be more useful and reliable
compare to the classical cane in order to provide fully automatic obstacle avoidance
with audible notification. Developments in embedded systems have opened up a vast
area of research and development for affordable and portable assistive devices for the
physically challenged. Besides, it is design to consume less power, portable in size
and has an acceptable accurate performance in object distance. This project aimed at
the design and implementation of a detachable unit which acts to augment the
functionality of the existing white cane, to allow knee-above obstacle detection.
However, due to its inherent limitation, the classical method does not provide the
protection for the body. Consequently, there is no guarantee that’s the presence of
obstacle, can be detected by the blind to avoid a collision. The cane developed helps
a blind person find way without any difficulty in terms of improving the social life
for the blind pedestrian.
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ABSTRAK
Projek ini bertujuan untuk membina satu alat bantuan pergerakan elektronik untuk
orang buta. Ia melibatkan teknologi ultrasonik dan dijangka dapat menggantikan
tongkat sedia ada. Ciri bagi alat bantuan ini termasuk menyediakan pengesanan
halangan automatik sepenuhnya melalui penghasilan bunyi. Selain itu, alat bantuan
perjalanan elektronik (ETA) ini, menjimatkan kerana penggunaan kuasa yang
minimum dan saiz yang kecil membolehkan ia dibawa dengan mudah.
Walaubagaimanapun, berdasarkan keadaan semasa, tongkat yang terdahulu tidak
dapat menyediakan perlindungan kepada tubuh badan. Oleh itu, tiada jaminan
kepada halangan yang bakal dihadapi dapat dikesan oleh orang buta pada masa yang
sama dapat mengelakkan daripada berlakunya perlanggaran. Selain daripada
meningkatkan kemajuan alat bantu terdahulu dan menggantikannya, ia merupakan
satu pembaharuan dalam peningkatan kehidupan sosial golongan orang kurang upaya
ini.
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TABLE OF CONTENTS
CHAPTER CONTENTS PAGE
TITLE I
VERIFICATION OF REPORT III
VERIFICATION BY SUPERVISOR IV
DEDICATION V
ACKNOWLEDGEMENT VI
ABSTRACT VII
ABSTRAK VIII
TABLE OF CONTENTS IX
LIST OF TABLES XIII
LIST OF FIGURES XIV
LIST OF ABBREVIATIONS XVI
LIST OF APPENDIX XVII
I INTRODUCTION 1
1.1 Project Background 1
1.2 Project Objectives 2
1.3 Problem Statements 3
1.4 Scope of Works 4
1.5 Advantages of Ultrasonic Cane 5
1.6 Thesis Summary 6
II LITERATURE REVIEW 7
2.1 Background of Cane 7
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2.2 Types of Cane 9
2.3 History of Cane 10
2.4 Canes Around The World 11
2.5 How The Ultrasonic Cane Works 11
2.6 Ultrasound Ranging 12
2.7 Functional Descriptions 13
2.8 Obstacles 14
2.9 Sensors 15
2.9.1 Type of sensor 16
2.10 Sonar Sensor 19
2.11 The MaxSonar-EZ1 20
2.12 Advantages Of Using Ultrasonic 21 Sensor Compared To Another Sensor
2.12.1 Advantages of ultrasonic sensor 21
2.12.2 Disadvantages of infra-red sensor 22
2.12.3 Disadvantages of laser 22
2.12.4 Another advantage 23
2.13 Feeding safe and confident 23
III METHODOLOGY 24
3.1 Hardware 24
3.1.1 The main board 25
3.1.2 Ultrasonic sensor 27
3.1.3 The Circuitries 27
3.2 Project Work Flow 30
3.3 Project Block Diagram 31
3.4 Software 33
3.5 Negotiation Common Obstacles 33
3.6 Obstacles 35
3.7 Angle Of The Cane 35
3.7.1 Beam Width 37
x
IV RESULTS AND ANALYSIS 39
4.1 Hardware Part 39
4.2 Result Obtained 41
4.2.1 Ultrasonic Board 41
4.2.2 Acceptable Voltage Indicator 45
4.3 Experimentation And User Validation 46
4.4 Detection Of Knee Above Obstacles 46
4.5 Negotiating Common Obstacle 48
4.6 Other Observation 48
4.7 Packaging 49
4.7.1 Casing 49
4.7.2 Specifications 49
4.8 Problems And Troubleshooting 50
4.8.1 Hardware 50
4.8.2 Software 50
4.9 Analysis 51
4.9.1 Angle Detection Zone 51
4.9.2 Audio Warning Zone 52
V DISCUSSION AND CONCLUSION 53
5.1 Discussion 53
5.2 Conclusion 55
VI FUTURE DEVELOPMENT 56
6.1 Introduction 56
6.2 Intelligent Cane 57
6.3 Conceptual Design 59
6.3.1 Device Needed 60
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VII REFERENCES 63
VIII APPENDIX 64
xii
LIST OF TABLES
NO TITLE PAGE
3.1 PIC PORT B Connection 26
3.2 PIC PORT A Connection 26
3.3 Division of Detection Range into Sub-Ranges and 36
Corresponding Patterns
4.1 Audio Warning Zone 52
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LIST OF FIGURES
NO TITLE PAGE
2.1 Long Cane 9
2.2 ID Cane 10
2.3 Ultrasound Based Ranging 13
2.4 Sonar Range Finder 21
3.1 Ultrasonic Sensor 27
3.2 The Power Supply Circuit 27
3.3 The Main Circuit 28
3.4 Acceptable Voltage Indicator Circuits 29
3.5 Process Flow Chart 30
3.6 Project Block Diagram 31
3.7 Path Finding 34
3.8 Side View Illustrating The Horizontal And Vertical Coverage Of
The Detection Zone
34
3.9 Detection Cone 36
3.10 Top Views Showing The Horizontal And Angular Coverage Of
The Detection Zone For Long Range Mode (left) and Short
Range Mode (right)
37
3.11 Four Different Scenarios Returning The Same Sensor Output 38
4.1 Ultrasonic Cane 39
4.2 Details Of Design 40
4.3 No Obstacle Detected 41
4.4 Obstacle Detected 42
4.5 PCB Layouts With Component Footprint 42
4.6 Component Footprint 43
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4.7 Original Size 43
4.8 Original Size Of Additional Circuit 45
4.9 Mirror Track. 46
4.10 Detection Of Raised Side Of A Truck 47
4.11 Detection Of Raised Horizontal Bar 47
4.12 Path Finding Experiment 48
4.13 Different Grips For Holding The White Cane 48
4.14 Predicted Detection Area 51
4.15 Actual Detection Area 51
4.16 Sounds Versus Distance 52
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LIST OF ABBREVIATIONS
PSM - Projek Sarjana Muda
IC - Integrated Circuit
PIC - Programmable Integrated Circuit
DC - Direct Current
AC - Alternate Current
I/O - Input or Output
IP/OP - Input Port or Output Port
LED - Light Emitting Diode
SONAR - SOund Navigation And Ranging
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LIST OF APPENDIX
NO TITLE PAGE A The ‘Smart’ Cane Project From Indian Institute Of 64 Technology Delhi B The MaxSonar-EZ1 High Performance Sonar Range Finder 68 C Sonar Explorer 70 D A Collection Of Ultrasonic Cane Project 72 E Project Cost 75 F Programming the PIC16F84 76
G PIC Projects 78 H Program Source Codes 80
CHAPTER 1
INTRODUCTION
1.1 Background
The Malaysian Association for the Blind (MAB) estimates that there are 63,000
people in the Malaysia, who are blind, and 53,000 people are having a bad blurry of
eye. Therefore, both the size of the market and the size of the need for the technology
proposing are large. The virtual cane coupled with an ordinary cane will allow
unprecedented navigational power to those who need it. Products developed for the
visually impaired have typically focused on communication devices such as reading
machines and embossing printers for Braille. Navigational aids beyond the cane have
yet to be developed in a manner leading to their acceptance by the visually impaired
community. The primary impediment to produce a marketable version of the
proposed technology is the form factor. The product must be easy to use and
lightweight. The potentially small size makes it a very attractive option for this
product. As more markets are developed for this technology, the sensor will be able
to be manufactured in high volume at very low cost. This is an added benefit for
those in need of affordable assistive navigational tools. As both technologies mature,
the virtual cane will be able to be mass produced and refined. The device proposes is
simple and should be no more difficult to use than an ordinary cane. The rich amount
of information available to the user is a tremendous benefit and the novel way in
which it is presented to the user make the virtual cane technology an important
milestone in assistive devices.
1.2 Objectives
In expanding the idea of helping the blind, two main objectives are the target to
be achieved upon completion of this project.
The first objective is to develop a model of cane for the blind. The most widely used
primary mobility aid today is the long cane. The goal of this design is to improve
upon the limitations of the long cane and to replace it.
The second objective is to design ETA prototype that consumes less power, portable
in size and has an acceptable accurate performance in object distance detection
(using sensor) in order to provide fully automatic obstacle avoidance with audible
notification.
The design of a small portable cane will be useful for the blind people. It is easier for
them to find ways on daily activities without having to use the standard mobility aid
available for individuals with this disability. Since the mobility aids are small and
light, it is easily, portable and can be taken anywhere.
2
1.3 Problem Statements
For aided orientation and mobility, majority of the blind people use a long cane,
which provide an extended spatial sensing within and are about 0.5 meters ahead of
the user. However, the long cane does not provide protection to their body. The long
cane has several limitations such as a range limited to the length of the cane,
typically one pace ahead of the user, difficulties detecting overhanging obstacles, and
safe storage in public places. Due to its inherent limitations, the long cane does not
provide protection for the body above the waist elevation. Consequently, there is no
guarantee that the presence of obstacles such as low slung signposts, utility boxes,
tree branches, overhanging wires, can be detected by the blind person in time to
avoid a collision.
An Electronic Travel Aid (ETA) is a form of assistive technology having the
purpose of enhancing mobility for the blind pedestrian. The blind people find
traveling difficult and hazardous because they cannot easily determine where things
are, a process otherwise known as spatial sensing. Thus the problem of mobility can
be reframed as a problem in spatial sensing. The techniques for spatial sensing are
well known, radar, sonar, and optical triangulation methods being the most common,
and the latter two have been incorporated into a wide variety of past ETA designs
[Duen Hsi Yen, 1996].
However, there are many problems with currently available devices. First, the
rangefinder technology is unreliable in its detection of step-downs or step-ups, such
as curbs. Secondly, blind users find the sounds of various pitches or tactile vibrations
being used to code the spatial information to be esoteric and difficult to understand.
Thirdly, most blind users do not find the slight improvement in mobility
performance to be worth the extra cost which can be many thousands of dollars, and
the additional worry of maintaining a complex, expensive battery operated system
that must be carried around and kept track of [Duen Hsi Yen, 1996].
3
1.4 Scope of Work
The motivation for this project was to design an electronic mobility aid for the
blind. The goal of this project is to design Electronic Travel Aid (ETA) for the blind
and to improve upon the limitations of the long cane and to replace it. It will
involved ultrasound technology to be more useful and reliable than classical cane.
The ultrasonic cane is use to allow the blind people for aided orientation and easy
mobility. The prototype is fitted in a ‘flashlight-like’ enclosure made of a PVC tube
with an external battery pack as power supply, an earphone for the audible output
and a range of 0 up to 1 meter.
The open ultrasonic sensor manufactured gold foil stretched over a grooved plate.
The grooved, metallic back plate in contact with the insulated side of the foil forms a
capacitor which, when charged, exerts an electrostatic force to the foil thus
transforming electrical energy into acoustical waves. Similarly the energy flow can
be reversed to transform the returning echo into electrical energy.
In this design, ultrasound is radiated out and the returning ultrasonic echo’s are
translated back down into the audible domain and presented binaurally to the blind
user. The time based cues responsible for spatial hearing are encoded upon the
sound, thereby creating the illusion of an externalized auditory image located out in
space at the detected object's position. In this approach, one of the significant
drawbacks is that the user must wear earphones, which can interfere with the
listening of normal environmental sounds.
4
1.5 Advantages of Ultrasonic Cane
Several advantages were identified during interaction with this product.
1.5.1 Light Weight Design
Since the cane is small and light; it is easily portable and can be taken anywhere.
This product is a lightweight rechargeable battery provides power. The unit should
be light in weight without adding extra weight to the existing cane and at the same
time without compromising in terms of strength, particularly impact strength and the
user should be able to use the unit at length without getting fatigued.
1.5.2 Low power consumption
PIC16F84A consist of 18-pin Enhanced FLASH/EEPROM 8-bit microcontroller. It’s
used the low power, high speed technology and the characteristic is <2mA typical @
5V, 4 MHz and 15 µA typical @ 2V, 32 kHz
1.5.3 Other Design Features
It is fully automatic obstacle avoidance with audible notification. All buttons on the
module should be non-protruding type and should possess Braille markings for easy
identification. Also all the above requirements have to be met within an affordable
cost target. The unit should be such that it has flexibility to be used by users having
different styles of holding and gripping.
5
1.6 Thesis Summary
This thesis consists of six (6) chapters which are Introduction, Literature Review,
Methodology, Results and Analysis, Discussion and Conclusion and Future
Development.
Chapter 1 is the introduction of the main idea including the advantage and
important of this project.
Chapter 2 is the literature review that discussed about the types of sensor will
be use in the development of the Ultrasonic Cane for the Blind project. This includes
the explanations about how will the cane works.
Chapter 3 is the methodology while focused on hardware and software design
of the Ultrasonic Cane. It will be focused on obstacle sensing which is using the PIC
Microcontroller as a main controller. In this section, software development such as
software compiler, software design will be discussed further.
Chapter 4 is results and analysis whereas all the results obtained and the
analysis of the project is identified. All discussions are concentrating on the result of
Ultrasonic sensor board. This chapter also discusses the problem that faced for this
project.
Chapter 5 is discussion and conclusion, will be discussed the conclusion for
this project after the entire task is completed.
Chapter 6 is future development that discussed the further development of the
project that can be added into the classification for improving.
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CHAPTER 2
LITERATURE REVIEW
2.1 Background of Cane
This research intends to bring "intelligence" into the long cane by providing
overhanging obstacle detection capabilities to the cane users. For this purpose, a self-
contained, miniaturized ultrasonic ranging module with microelectronics will be
designed, prototyped, and integrated into the shaft of a long cane. Upon obstacle
detection, a human voice signal, describing in key words the distance and height of
the obstacle, will be displayed to provide orientation assistance. Compared to
electronic travel aids (ETAs) developed in the past, the "smart" long cane will be
ergonomic in design, easy to use, easy to maintain, less expensive, and much more
compatible with daily travel situations. It will provide a useful tool to the blind
community in terms of increased mobility, which is a prerequisite for employment
and an independent, substantial social life.
10% of people considered legally blind also have mobility impairment,
leading to reliance on others for mobility. Although there are limited specialty
options available for blind people with mobility impairments, people have been
successful using the current obstacle detection options like ultrasonic or infrared
sensors.