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

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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

xvi

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.