DESIGN OF A LOW COST PORTABLE HEART BEATS MONITOR USING

INFRARED SENSOR

AHMAD HARRIS BIN ABD HAMID

This report is submitted in partial fulfillment of the requirements for the award of

Bachelor of Electronic Engineering (Industrial Electronic)

Faculty of Electronic and Computer Engineering

Universiti Teknikal Malaysia Melaka

JUNE 2013

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Special Dedication towards my beloved family,

Supervisor and friends

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ACKNOWLEDGEMENT

In the name of Allah, the Most Gracious, the Most Powerful and the Most

Merciful Alhamdulillah, all praises to Allah for the strengths and His blessing in

completing this final year project and thesis. I had put my full effort and dedicated to

finish this final year project and thesis as it is partial fulfilment or requirements for

the degree of Bachelor in Electronic Engineering (Industrial Electronic).

Special appreciation goes to my supervisor, Dr Mai Mariam Binti Mohamed

Aminuddin, for her supervision and constant support. Her invaluable help of

constructive comments and suggestions throughout along one year of duration for

final year project have contributed to the success of this project.

Sincere thanks to all my friends for give me motivation and boost my effort

to finish this project. Thanks for the friendship and memories.

Last but not least, my deepest gratitude goes to my beloved parents; Abd

Hamid B Deraman and Zainalriah Bt Abdul Manan and also to my brother and

sisters for their endless love, prayers and encouragement. To those who indirectly

contributed in this project, your kindness means a lot to me.

Thank you very much

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ABSTRACT

A Low Cost Portable Heart Beats Monitor using Infrared Sensor is a medical-

related project function as a low cost portable device to measure a heart rate in real-

time condition. In this project, Infrared LED and photodiode has been used as a

sensor to measure a heart rate and a microcontroller act as controller to process the

input and output of the device. The development of the prototype as an assist device

for a user with has a busy lifestyle to monitor their heart rate at any places. Parallel to

this need, the prototype is a portable and low cost design. The development of the

prototype starts with the designing the sensor circuit, signal conditioning circuit,

voltage regulator circuit and microcontroller circuit. After the functionality test,

these circuits will integrate with the output display. The prototype design is able to

display the heart rate measurement in beat per minute (BPM) and the condition of

heart rate either low heart rate or normal heart rate or high heart rate. Then, the LEDs

function as an indicator to shows the normality or abnormality condition.

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ABSTRAK

Projek Pengukur Dengutan Jantung Mudah Alih Berkos Rendah

menggunakan Pengesan Inframerah adalah projek berkaitan perubatan yang berfungi

sebagai alat mudah alih yang kos rendah untuk mengesan kadar denyutan jantung

pengguna dalam keadaan langsung. Pemancar inframerah dan foto diod digunakan

sebagai keadah untuk mengukur kadar denyutan jantung subjek dan mikropengawal

digunakan untuk mengawal masukan dan keluaran alatan ini. Protaip ini dihasilkan

bagi membantu pengguna yang sibuk dengan aktiviti seharian untuk memantau kadar

denyutan jantung mereka dimana sahaja mereka berada. Dengan itu, konsep mudah

alih dan kos rendah diterapkan di penghasilan projek ini. Ini bertepatan dengan

objektif projek iaitu untuk membina alat mengukur dengupan jantung yang mudah

alih dan kos rendah. Projek ini dimulakan dengan mereka litar bagi pengesan, litar

penguat dan penapis, litar pengawal voltan dan litar mikropengawal. Kesemua litar

ini diuji funginya dan digabungakan dengan hasil keluaran. Prototaip ini akan

memaparkan nilai denyutan jantung setiap minit (bpm) pada papan pemapar dan

nyalaan diod pemancar cahaya bagi menentukan kadar denyutan jantung berada

dalam keadaan normal atau sebaliknya.

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TABLE OF CONTENT

CHAPTER TITLE PAGE

PROJECT TITLE i

VERIFICATION ii

DECLARATION iii

APPROVAL iv

DEDICATION v

ACKNOWLEDGEMENT vii

ABSTRACT vii

ABSTRAK viii

TABLE OF CONTENT ix

LIST OF TABLES xii

LIST OF FIGURES xiv

LIST OF SYMBOLS & ABBRERIATION xvi

1 INTRODUCTION

1.1 Introduction 1

1.2 Objective 2

1.3 Problem Statement 2

1.4 Scope of Work 2

1.5 Thesis Overview 3

2 LITERATURE REVIEW

2.1 Overview 5

2.2 Introduction of Heart Rate 5

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2.2.1 The Heart Rate Measurement Method 6

2.2.2 The Electricity of Heart 7

2.3 The Heart Rate Monitor 8

2.3.1 Introduction of Heart Rate Monitor 8

2.3.2 The Construction of Heart Rate Monitor 9

2.3.2.1 Block Diagram 9

2.3.2.2 Infrared Sensor 10

2.3.2.2.1 Principle of Infrared Sensor 10

2.3.2.2.2 Type of Infrared Sensor 10

2.3.2.3 Dual Operational Amplifier, MCP602 11

2.3.2.3.1 Introduction of MCP602 11

2.3.2.3.2 Features of MCP602 12

2.3.2.4 Microcontroller PIC 16F628A 13

2.3.2.4.1 Introduction of PIC 16F628A 13

2.3.2.4.2 Features of PIC 16F628A 13

2.3.2.5 LCD Display 16x2 14

2.3.2.5.1 Introduction of LCD 14

2.3.2.5.2 Features of LCD 16x2 14

2.3.2.5.3 The advantages of LCD 15

2.4 Existing Heart Rate Monitor Construction 15

2.4.1 Heart Rate Measurement from the Finger 15

using a Low-cost Microcontroller 16

2.4.2 Microcontroller Based Heart Rate

Monitor using Fingertip Sensors 16

3 METHODOLOGY

3.1 Overview 17

3.2 Project Flow Chart 18

3.3 Block Diagram 19

3.3 Project Methodology 19

3.4.1 Circuit Development 19

3.4.1.1 Sensor Circuit 20

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3.4.1.2 Signal Conditioning Circuit 20

3.4.1.3 Voltage Regulator Circuit 24

3.4.1.4 Microcontroller and Output Circuit 24

3.4.2 Hardware Development 25

3.4.3 Software Development 25

3.4.4 Hardware and Software Development 26

3.4.5 Testing 26

3.4.5.1 The Reliability and Consistency Test 26

3.5 Expected Result 28

3.6 Project Planning 29

3.6.1 Overall Project Flow Chart 29

3.6.2 Gantt Chart 30

4 Result Analysis and Discussion

4.1 Overview 31

4.2 Result for the Reliability and Consistency Test 31

4.2.1 Wilcoxon rank sum test for Test 1 32

4.2.2 Wilcoxon rank sum test for Test 2 33

4.2.3 Wilcoxon rank sum test for combination of

Test 1 & Test 2 34

4.3 Discussion 35

4.3.1 Project Discussion 35

4.3.2 Importance of the project design for

sustainable development 36

4.3.3 Impact for commercialization and

research advancement 37

5 Conclusion and Future Work

5.1 Overview 38

5.2 Conclusion 38

5.3 Future Work 39

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References 40

Appendix A 42

Appendix B 46

Appendix C 49

Appendix D 52

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LIST OF TABLES

TABLE TITLE PAGE

3.4.2 Gantt Chart 30

4.2.1 Data sample for Test 1 32

4.2.2 Data sample for Test 2 33

4.2.3 Data sample for Test 1 and Test 2 34

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LIST OF FIGURES

FIGURE TITLE PAGE

2.2.1.1 Manual Method 6

2.2.1.2 Monitor Method 6

2.2.2.1 Myocardium electricity activity 7

2.3.2.1 The block diagram of heart rate monitor 9

2.3.2.2 Illustration of infrared sensor 10

2.3.2.3.1 The packaging for MCP602 12

2.3.2.4.1 The packaging of PIC 16F628A 13

2.3.2.5 LCD Display 16x2 pins 14

2.4.1 The block diagram of heart rate monitor 15

2.4.2 The block diagram of heart rate monitor 16

3.2 The flow chart of the prototype development 18

3.3 The block diagram of the project 19

3.4.1.1 The design of sensor circuit 20

3.4.1.2 The design of signal conditioning circuit 20

3.4.1.2(a) The simulation of Oscilloscope 22

3.4.1.2(b) The simulation of Bode Plotter 23

3.4.1.3 The design of Voltage regulator circuit 24

3.4.1.4 The design of microcontroller and output Circuit 24

3.4.2 The PCB circuit 25

3.4.4 The hardware and software integration 26

3.4.5.1 The example of Wilcoxon rank sum test in Matlab software 28

3.6.1 The overall project flow chart 29

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4.2.1 Wilcoxon rank sum test for Test 1 using Matlab simulation 32

4.2.2 Wilcoxon rank sum test for Test 2 using Matlab simulation 33

4.2.2 Wilcoxon rank sum test for combination of Test 1 & Test 2

using Matlab simulation 34

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LIST OF SYMBOLS & ABBRERIATION

bpm - beats per minutes

ECG - Electrocardiogram

LCD - Liquid crystal display

LED - Light-emitting diode

PCB - Printed circuit board

ADC - Analog to digital converter

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CHAPTER 1

INTRODUCTION

1.1 Introduction

Heart rate measurement could show the condition of the heart. Heart rate is

varying according to age, person physical and activity condition. Human heart rate

for adult that healthy is around 60 to 100 beats per minute (bpm) [1]. While for an

athlete, his/her heart rate is slower than an active adult [2]. For baby on the other

hand, the heart rate is higher which is around 120 to 160 bpm and for their children’s

heart rate is around 75 to 110 bpm [1]. Abnormal heart rate such as lower heart rate

than the normal rate is called bradycardia whereas for a higher heart rate which is

higher than the normal is called tachycardia [1].The traditional heart rate is

measurable by putting finger above pulse artery and count pulse rate within 30

second and heart rate (bpm) can be found with multiply with 2 [1]. This way is easy

but inaccurate especially when artery pulse state in high rate. The most accurate

method to measure heart rate is by using electrocardiogram machine (ECG) [3] but

this equipment expensive and not affordable by individuals.

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1.2 Objective

The main objective of this project is to design and develop a low cost

portable heart beats monitor using infrared sensor. The prototype is a low cost

portable device that can extract and display the heart rate by count the pulse generate

by the infrared sensor. The signal is extracted from the fingertip placed in between

infrared transmitter LED and a photo diode sensor. The pulses generates at the

output of the photo diode sensor is too small to be detected directly by a

microcontroller. Therefore, a two-stage high gain, active low pass filter is designed

using two Operational Amplifiers to filter and amplify the signal to appropriate

voltage level so that the pulses can be counted by a microcontroller. The heart rate is

displayed on a LCD display and LED as an indicator for normality or abnormality

heart rate condition.

1.3 Problem Statement

A traditional approach of heart monitoring has always meant that people is

going to hospital where a cardiologist or medical officer will examine the patient for

any heart diseases. The standard Electrocardiogram (ECG) machine normally found

in big hospitals due to the high cost and requires a specialist to handle the machine.

This will contribute high medical cost for the patients. The development of a low

cost portable heart beats monitor using infrared sensor will be the foundation for an

inexpensive portable heart rate monitor. This prototype would benefit the users to

monitor their heart rate at home or any place.

1.4 Scope of Work

The purpose of this project is to obtain the output signal form the infrared

sensor. The infrared sensor is used to measure the cardiovascular pulse wave that is

found throughout human body. This pulse wave will result in a change in the volume

of arterial blood with each pulse beats. This change in blood volume can be detected

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in peripheral parts of the body such as fingertip using a technique called

Photoplethysmosgraphy. The infrared sensor consists of:

An infrared LED transmitter

A photo diode sensor

An infrared LED that transmits an IR light through the fingertip of the

subject, a part of which is reflected by the blood cells. The reflected signal is

detected by a photo diode sensor. The changing blood volume with heartbeat results

in a train of pulses at the output of the photo diode, the magnitude of which is too

small to be detected directly by a microcontroller. Therefore, a two-stage high gain,

active low pass filter is designed using two Operational Amplifiers to filter and

amplify the signal to appropriate voltage level so that the pulses can be counted by a

microcontroller. The dual Operational Amplifier, MCP602 is used to amplify the

signal and PIC 16F628A used as a microcontroller. The heart rate is displayed on a

LCD display and LED as an indicator for normality or abnormality heart rate

condition.

1.5 Thesis Overview

The thesis structure is divided into five main chapters. There is Chapter 1:

Introduction, Chapter 2: Literature Review, Chapter 3: Project Methodology, Chapter

4: Result Analysis and Discussion and Chapter 5: Conclusion and Future work.

For Chapter 1: this chapter briefly explained the background of this project.

Starting with the introduction of this project, that is why this project is chosen. Later,

this chapter will also cover about the problem statement that brings to the idea to

realize this project. Other parts of this chapter will also discussing about the

objectives, scope of studies, and also the project methodology.

For Chapter 2: this chapter briefly explained about the present theory and

concept related to the project. This chapter also discuss about the basic construction

of the heart rate monitor and the existing related project.

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For Chapter 3: this chapter briefly explained the method to develop the

prototype. This is including the hardware design and software design. The hardware

design focus on the designing circuit sensor, signal conditioning circuit and

microcontroller circuit. The software design focuses on the development of

microcontroller instructions coding using MikroC Pro for PIC software.

For Chapter 4: this chapter briefly explained the result for testing method.

The data will record into table for easy observation. Moreover, the result will be

analyze and discuss to get better understanding about the result.

For Chapter 5: this chapter concluding the finding in this project. In addition,

this chapter also included the several aspect involve in overall project such as the

project achievements and the learning outcomes. Also will be discussed in this

chapter is the future recommendation for future study and prototype development

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CHAPTER 2

LITERATURE REVIEW

2.1 Overview

This chapter briefly explains about the present theory and concept related to

the project. This chapter also discuss about the basic construction of the heart rate

monitor and the existing related project.

2.2 Introduction of Heart Rate

Heart rate is the number of heartbeats per unit of time, typically expressed as

beats per minute (bpm). Heart rate can vary as the body's need to absorb oxygen and

excrete carbon dioxide changes during exercise or sleep. The heart rate of a healthy

adult [2] at rest is around 72 beats per minute (bpm). Athletes normally have lower

heart rates than less active people. Babies have a much higher heart rate at around

120 bpm, while older children have heart rates at around 90 bpm. Lower than

normal heart rates are usually an indication of a condition known as bradycardia,

while higher than normal heart rates are known as tachycardia [3]. The measurement

of heart rate is used by medical professionals to assist in the diagnosis and tracking

of medical conditions. It is also used by individuals.

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2.2.1 The Heart Rate Measurement Method

The heart rate can be measure at any spot on the body at which an artery is

close to the surface and a pulse can be felt. The most common places to measure

heart rate using the palpation method is at the wrist (radial artery) and the neck

(carotid artery). There are several others places that can measure heart rate such as

elbow (brachial artery) and groin (femoral artery) [2]. The methods of measuring

heart rate can be divided into two:

Figure 2.2.1.1: Manual method

(Source by: http://www.topendsports.com/testing/heart-rate-measure.htm)

The subject needs to place their fingers either at neck or wrist. For neck area

the carotid pulse will be measure and wrist area the radial pulse will be measure.

Then the subject needs to estimate the beats per minute rate by counting over 10

seconds and multiplying this figure by 6, or count over 15 seconds and multiply by 4,

or over 30 seconds and doubling the result. There are obvious potential errors by

using this shorthand method [2].

Figure 2.2.1.2: Monitor method

(Source by: http://www.topendsports.com/testing/heart-rate-measure.htm)

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The monitor method can be performing by using electrocardiogram (ECG)

machines. The standard Electrocardiogram (ECG) machine normally found in big

hospitals due to the high cost and requires a specialist to handle the machine. The

ECG concept also applied on several gadgets such as watch and smartphone but the

demand is not good due to the high price [2].

2.2.2 The Electricity of Heart

Electrical heart activity is based on depolarization and re-polarization of

myocardial cells. The electrical impulse starts in the sinuatrial node (natural

pacemaker) flowing through the atriums to reach the atrioventricular node and

generating the atrium contraction. The current then flows through the Hiz Bundle

reaches the ventricles and flows through them generating the ventricular

contractions. Finally, the current reaches the Purkinje fibers and re-polarization of

the heart tissue occurs [4].

Figure 2.2.2.1: Myocardium electrical activity

(Source by: Casillas, C. (2010). Heart Rate Monitor and Electrocardiograph Fundamentals)

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This is a list of events that occur in the heart on each heartbeat. Figure 2.2.2.1 shows

heart behavior and part of the generated signal also known as QRS complex:

1. Atrium begins to depolarize

2. Atrium depolarizes

3. Ventricles begin to depolarize at apex. Atrium repolarizes

4. Ventricles depolarize

5. Ventricles begin to repolarize at apex

6. Ventricles repolarize

(Source by: Casillas, C. (2010). Heart Rate Monitor and Electrocardiograph Fundamentals)

2.3 The Heart Rate Monitor

2.3.1 Introduction of Heart Rate Monitor

Heart rate is a useful indicator of physiological adaptation and intensity of

effort. Therefore, heart rate monitoring is an important component of cardiovascular

fitness assessment, training programs and so on. The electrocardiogram (ECG) and

Holter’s monitoring devices are accurate, but not feasible for use in field setting due

to cost, size and complexity of operation. Light-weight telemetric heart rate monitors

equipped with conventional electrodes have been available since 1983 and have

proved to be accurate and valid tools for heart rate monitoring and registering in field

measurements[5]. A heart rate monitor is a device that allows a user to measure

his/her heart rate in real time.

The heart rate monitor was invented by the Australian physicist, Robert

Treffene. He appeared on the television show The New Inventors with his device that

made with swimmers in mind[6].

The first ECG accurate wireless heart rate monitor was invented by Polar

Electro in 1977 as a training tool for the Finnish National Cross Country Ski Team.

The concept of intensity training by heart rate swept the athletic world in the eighties.

By the 1990’s individuals were looking to heart rate monitors not only for