1

LED BLOOD PRESSURE PORTABLE MONITOR

HAZIQ AKMAL BIN ABDUL RAZAK

51116212210

UMMU ATYYAH BINTI MOHAMAD ISA

51116211042

REPORT SUBMITTED TO FULFILL THE PARTIAL REQUIREMENTS

FOR THE DIPLOMA OF ENGINEERING IN MEDICAL ELECTRONICS

UNIVERSITI KUALA LUMPUR

S2/ 2014

2

DECLARATION

We declare that this report entitle Led Blood Pressure Portable Monitor is the results

of our own research excepts as cited in the references. The report has not been

accepted for any degree and is not concurrently submitted in candidature of any other

degree.

Signature:

Name: HAZIQ AKMAL BIN ABDUL RAZAK

Date: JANUARY 2015

Signature:

Name: UMMU ATYYAH BINTI MOHAMAD ISA

Date: JANUARY 2015

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APPROVAL

I have examined this report and verify that it meets the program and University

requirements for the Diploma of Engineering Technology in Medical

Electronics, University of Kuala Lumpur British Malaysian Institute.

Signature: ..

Date: ..

Supervisors Name: NORROLHODA BT SANIF

Official Stamp: ..

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ACKNOWLEDGEMENT

Alhamdulillah. Thanks to Allah SWT, whom with His willing giving us the opportunity

to complete this Final Year Project which the title is LED Blood Pressure Portable Monitor.

This final year project report was prepared for Engineering Technology in Medical Electronics

Section, UniKL British Malaysian Institute (UniKL BMI), basically for student in final year to

complete the undergraduate program.

Firstly, we would like to express our deepest thanks to, Miss Norrolhuda bte Mohd

Sanif, a lecturer at Engineering Technology in Electrical Section UniKL BMI and also assign,

as our supervisor who had guided be a lot of task during two semesters session during

Engineering Design (Semester 4 ) and Final Year Project (Semester 5). We also want to thank

the lecturers and staffs in Engineering Technology in Medical Electronics and Electronics

Section UniKL BMI for their cooperation during completing our final year project that had

given valuable information, suggestions and guidance in the compilation, gave the permission

to use all required machinery and the necessary material to complete the project and

preparation for this final year project report.

Deepest thanks and appreciation to our parents, family and others for their cooperation,

encouragement, constructive suggestion and full of support for the report completion, from the

beginning till the end, that have been contributed by supporting our work and help ourselves

during the final year project progress till it is fully completed.

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ABSTRACT

Existing blood pressure tests are painless but the equipment is flawed, it was delicate

and impractical in many settings, and it contains mercury, which is toxic when released into the

environment. It was also prone to human error, because it depends on a doctor listening to the

patients pulse through a stethoscope. The LED Blood Pressure Portable Monitor is a device

that can measure users blood pressure through an inflatable hand cuff. In this system, an

inflatable hand cuff contains an electronic pressure sensor that measures the air pressure. Using

PIC18F2321 controller that able to stimulate the measurement. The combination of hardware

and PIC programming can be determine of blood pressure reading that intergrated with pressure

sensor. The element operates in oscillometric principles gives the result in terms of systolic and

diastolic. For more preferable we convert the result into LED . Green LED indicates (pass) ,

Red LED indicates (fail), while Yellow LED indicates (status) and lastly Clear LED indicates

(power).

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TABLE OF CONTENT

CHAPTER TITLE PAGE

TITLE PAGE 1

DECLARATION

2

APPROVAL

3

ACKNOWLEDGEMENT

4

ABSTRACT

5

TABLE OF CONTENT

6

LIST OF TABLE

9

LIST OF FIGURE

10

1 INTRODUCTION 12

1.1 INTRODUCTION OF CHAPTER 13

1.2 PROJECT BACKGROUND 14-15

1.3 PROBLEM STATEMENT 16

1.4 OBJECTIVES 16

1.5 PROJECT SCOPE AND LIMITATION 17

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1.6 THESIS OUTLINE 18

1.7 SUMMARY 19

2 LITERATURE REVIEW 20

2.1 INTRODUCTION OF BLOOD PRESSURE 21-22

2.2 BLOOD PRESSURE DISEASES 22-23

2.3 PREVIOUS WORK 23

2.3.1 METHOD OF MEASURING ARTERIAL BLOOD

PRESSURE 23-25

2.3.2 OSCILLOMETRY METHOD 25-27

2.3.3 MEASUREMENT PROCEDURES 27-30

2.3.4 BLOOD PRESSURE READING 30-31

2.4 PRESENT WORK 31

2.5 SUMMARY 32

3 METHODOLOGY 33

3.1 INTRODUCTION 34

3.2 BLOCK DIAGRAM 34-35

3.2.1 BLOCK DIAGRAM EXPLAINATION 35

3.3 HARDWARE AND SOFTWARE DEVELOPMENT 36-37

3.3.1 HARDWARE DEVELOPMENT 37-47

3.3.2 PROJECT STEPS 47-53

3.3.3 SOFTWARE DEVELOPMENT 53-54

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3.4 SUMMARY 55

4 RESULT AND ANALYSIS 56

4.1 INTRODUCTION 56-58

4.2

RESULT 59-61

4.3 ANALYSIS 61

4.4 SUMMARY 61

5 CONCLUSION AND RECOMMENDATION 62

5.1 CONCLUSION 63

5.2 RECOMMENDATION 63-64

REFERENCES 65-66

APPENDICES 67-80

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LIST OF TABLE

TABLE NO TITLE PAGE

3.1 Process of building the hand casing 47

4.1 The result of the project 58

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LIST OF FIGURE

FIGURE NO TITLE PAGE

2.1 A recording of cuff pressure 26

2.2 Position of the arm and placement of the cuff 26

2.3 Measurement of the arm circumference 30

2.4 Blood Pressure condition and Systolic/Diastolic

Reading 31

2.5 LED Blood Pressure Portable Monitor 31

3.1 Block diagram of LED Blood Pressure Portable

Monitor 34

3.2 Schematic diagram of the component on breadboard 38

3.3 All the electronic components on the breadboard 38

3.4 Voltage regulator schematic diagram 39

3.5 Pressure Sensor schematic diagram 40

3.6 PIC18F2321 microcontroller schematic diagram 41

3.7 PCB Board design 42

3.8 PCB on the transfer paper 43

3.9 Process of ironing the PCB 44

3.10 PCB in the etching solution 44

3.11 Drying the PCB 45

3.12 Soldering all the components 45

3.13 PCB process complete 46

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LED BLOOD PRESSURE PORTABLE MONITOR

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CHAPTER 1

INTRODUCTION

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1.1 INTRODUCTION OF CHAPTER

Blood pressure is a measure of how hard the blood pushes against the walls of your

arteries as it moves through your body. It's normal for blood pressure to go up and down

throughout the day, but if it stays up, you have high blood pressure. Another name for high

blood pressure is hypertension. When blood pressure is high, it starts to damage the blood

vessels, heart, and kidneys. This can lead to heart attack, stroke, and other problems.

High blood pressure is called a "silent killer,'' because it doesn't usually cause symptoms

while it is causing this damage. Your blood pressure consists of two numbers: systolic and

diastolic. Someone with a systolic pressure of 120 and a diastolic pressure of 80 has a blood

pressure of 120/80, or "120 over 80." Blood pressure is measured in millimeters of mercury

(mm Hg).

It is undeniable that nowadays people are more aware of the health conditions. One of

the most widely used methods to test the health conditions of an individual is to measure

his/her blood pressures. As ones of those who are concerned about their health, we decided to

work on this project LED Blood Pressure Portable Monitor because we would like to build

something that is useful and useable in real life.

This chapter will explain about the project background, project statement, the

objectives, scope of project/limitation, thesis outline and summary to complete this project.

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1.2 PROJECT BACKGROUND

In a nutshell, the idea to produce this product comes from an existing product. By

comparing the previous work and the present work, both are similar parts but there are some

parts in present work that had been upgraded. So that, it shows the innovative version of the

marketed product, which improves its efficiency and saves production costs. To ensure the

completion of the project, objectives were set as guidelines. At the end of the project, these

objectives will be reviewed and be proven or otherwise.

The reason to develop this project is because blood pressure is very important

measurement of human being. Blood pressure is an essential part of the way your body works.

Your blood carries oxygen and nutrients around your body and is pumped by your heart. Your

blood is under pressure as a result of the pumping action of your heart and the size and

flexibility of your arteries, which carry your blood.

Specifically, the national prevalence of hypertension in Malaysia based on the National

Health and Morbidity Survey (NHMS) III in 2012 was 52.2% for residents aged 18 years and

above.Most were unaware that they had hypertension, while those who were aware and on

treatment, most did not have controlled blood pressure. Therefore, we might also consider

getting a blood pressure monitor to use yourself at home on a regular basis.

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This final project is to design and build a portable blood pressure monitor device that

can measure a user's blood pressures and heart rate through an inflatable hand cuff. The device

is consisted of three main parts: external hardwares (such as cuff, motor, valve, and led), analog

circuit, and microcontroller.

The analog circuit converts the pressure value inside the cuff into readable and usable

analog waveforms. The Microcontroller Unit (MCU) samples the waveforms and performs

Analog to Digital Converter (ADC) so that further calculations can be made. In addition, the

MCU also controls the operation of the devices such as the ON/OFF button and Light Emitting

Diode (LED). The output of this project are systolic and diastolic of blood pressure.

The word 'portable' in our title, refer to all of the components are put together in one

package which allows a user to take it anywhere and perform a measurement whenever and

wherever they wants.

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1.3 PROJECT STATEMENT

Existing blood pressure tests are painless but the equipment is flawed, it was delicate and

impractical in many settings, and it contains mercury, which is toxic when released into the

environment. It was also prone to human error, because it depends on a doctor listening to the

patients pulse through a stethoscope. The combination of medical electronics and electrical

knowledge are important in this project because we used human blood pressure as an input of

the device and display the LED as the output.

1.4 OBJECTIVES

To build the blood pressure monitor that can be used by a user without need to use the

stethoscope.

To design the system that used to pump the air into the cuff manually.

To display the result through LED for a user.

To design LED Blood Pressure Portable Monitor with affordable price that can do by

own self or another word known as Do It Yourself (DIY)

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1.5 PROJECT SCOPE AND LIMITATION

Project scope:

a) Only use an inflatable arm cuff contains an electronic pressure sensor that measures the

air pressure inside the cuff

b) This project is easy to use and handle

c) Can bring this project due to its small size

d) Cost saving

Project limitation:

a) Location of sensor must be below the heart level due the concept of blood pressure

b) Only use battery to get power supply

c) This project only focusing on determining the blood pressure

d) The user must be in total rest condition

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1.6 THESIS OUTLINE

This thesis consists of five chapters. Chapter 1 discusses about the introduction of the

chapter, the main objective, project background, project statement, scope of the project and

limitation, thesis outline and summary of the project. Chapter 2 will discuss more on history,

theory and literature reviews that have been done. This part also consists of blood pressure

reading, the measurement method that will use and the components that use to design this

project included hardware and software.

In Chapter 3, the discussion will be on the methodology hardware and software

implementation. Block diagram and schematic diagram used in the project also included. The

result and discussion will be presented in Chapter 4.Problem encountered and solutions during

project development. Chapter 5 is discussing the conclusion and recommendation of this

project and future work that can be done.

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1.7 SUMMARY

This project design the small casing that can easy to bring anywhere. In conclusion, the

design and development of a LED Blood Pressure Portable Monitor device is presented that it

can measures the blood pressure range (pass or fail) efficiently in a short time and with less

expense without using time consuming and expensive clinical pulse detection systems. By

using analog signal processing techniques we can keep the device simple and to efficiently

suppress the disturbance in signals. To summarize, simulations showed that the blood pressure

can be detected from an inflatable arm cuff contains an electronic pressure sensor.

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CHAPTER 2

LITERATURE REVIEW

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2.1 INTRODUCTION

Blood pressure, which is basically the force that blood exerts on the inner walls of a

vessel, is an important determinant in the flow of blood in the body. When the heart is

contracting during ventricular systole, the maximum pressure exerted against the walls of the

arteries is systolic pressure. During relaxation of the ventricle, the pressure that results is

termed diastolic pressure. These pressures are measured in millimeters of mercury (mmHg.).

The typical adult blood pressure is 120/80 mmHg. Young people may have lower values.

Blood pressure is one of most important measurements which indicate

persons health condition. Abnormal blood pressure reading may indicate

diseases which can be prevented by treatment. Blood pressure usually known as silent killer

that can be either cardiac disorder or the malfunctions of our body systems. Statistic shows that

the great number of cases for the past decades, which triggers the insight to prevent and

control this disease rather than cure it. Nowadays, the need for a reliable medical

technologies and analysis is desirable, since the users prefer to experience their medical

diagnosis themselves. Home monitoring provides an accurate record of measurements over

time helps in planning as a smart way to measure personal health condition. Furthermore,

blood pressure management is a step towards a healthier lifestyle.

A relatively ancient mercury column can be a good device for explaining how blood

pressure is measured. With a stethoscope illustrating the Korotkoff sounds and the mercury

sphygmomanometer showing the pressure differential, it is easy to explain the basis of the

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measurements. The newer electronic instruments have a similar problem with sensitivity to

sounds as well as overall accuracy [1].

2.2 BLOOD PRESSURE DISEASES

Today, people not care about their health that will cause disease and usually come

from the unbalance food taken. For example, the unlimited fat habit taken who will cause

elasticity of blood vessel determines the amount of blood flow at one time. The

nature of blood vessel changes as we age, as the vessel gets thicker, the capability of

blood vessel to absorb is diminishes with time. These causes the older people are more

likely to experience hypertension. Some people also may suffer low blood pressure

(hypotension) due to low blood volume in their body system.

Generally, high blood pressure is related to high salt intake in our food consumption.

Since people nowadays are exposed to busy life routines made them consuming bad diet

habit which eventually promotes obesity (overweight). Cigarette habit and alcohol intake

may also contribute to this problem. The main factor that people expose to this hypertension is

lack of exercise and unbalance foot taken in daily routine. This high blood pressure problem

also related to some people who have the history of high blood pressure in their families that

have been identified to be one of the hypertension reasons. Beside that, people who are on

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medication or under doctors prescription need to observe the irregularities in their

blood pressure. Certain hormones, like adrenaline which is released when people under stress

may also cause certain blood vessels to constrict, and this raises the blood pressure. [2]

2.3 PREVIOUS WORK

2.3.1 METHOD OF MEASURING ARTERIAL BLOOD PRESSURE

The circulation of blood within the body has been a subject of study for many thousands

of years. In ancient times, the Chinese recognized the fact that blood circulated through the

blood vessels and developed theories on how such systems worked. Evidence also suggests that

scholars in India had developed some knowledge of the circulatory system, with an emphasis

on the pulse and its dynamic nature. [3]

A broader understanding of circulation and the circulatory system was developed in the

early 1600s by a doctor named William Harvey. He began teaching about circulation in 1615

and later published his work in 1628 entitled Exercitatio Anatomica de Motu Cordis et

Sanguinis in Animalibus (On the Movement of the Heart and Blood in Animals). His work

became a foundation for the study of the circulatory system, and is still highly regarded even to

this day. [4]

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Once the correlation between heart rate and pulse was discovered, it was possible to determine

blood volume and blood pressure. In 1733 Reverend Stephen Hales recorded the first blood

pressure measurement on a horse. He did this by inserting a long glass tube upright into an

artery, observing the increase in pressure as blood was forced up the tube. [5]

In 1881, the first sphygmomanometer was invented by Samuel Siegfried Karl Ritter von

Basch. It consisted of a rubber bulb that was filled with water to restrict blood flow in the

artery. The bulb was then connected to a mercury column, which would translate the pressure

required to completely obscure the pulse into millimeters of mercury. In 1896, the device was

further improved by Scipione Riva-Rocci. Improvements included a cuff that could be affixed

around the arm to apply even pressure to the limb that would become the standard design for

such devices going forward. [6]

Modern blood pressure measurement was not developed until 1905, when Dr. Nikolai

Korotkoff discovered the difference between systolic blood pressure and diastolic blood

pressure. These pressures corresponded to the appearance, and disappearance of, sounds within

the arteries as pressure was applied and then released. Known as Korotkoff sounds, the use of

systolic and diastolic sounds is now standard in blood pressure measurement.

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Since that time, further advances have been made to sphygmomanometers. Now available

in a variety of styles ranging from mercurial to aneroid and electronic versions, blood pressure

measurement has become more accurate and widely accepted as an important vital sign when

diagnosing a patient.

2.3.2 OSCILLOMETRY METHOD

This method predates the method of Korotkoff but was not originally as popular.

However, it is now the standard method for automated Blood Pressure measurement. In 1885

the French physiologist Marey observed that, if he placed a patients arm in a pressure

chamber then the pressure of the chamber would fluctuate with the pulse and the magnitude of

the fluctuation would vary with the pressure of the chamber. It is now known that these

fluctuations correspond to the occluding effect on the artery of pressure applied uniformly to

the arm and that the same effect can be observed in the pressure of an occluding cuff.

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Figure 2.1 : A recording of cuff pressure graph

Figure 1 above shows the fluctuations observed in an occluding cuff as the pressure is

initially raised and then gradually dropped. The second graph shows the cardiac synchronous

oscillations present in the cuff pressure which, as indicated above, vary with the cuff pressure.

Intuitively, one might suspect that the onset of the oscillations would occur at systolic

pressure and the disappearance of the oscillations would occur at diastolic pressure. In fact, the

onset of oscillations actually occurs well above systolic pressure and the oscillations do not

disappear until well below diastolic pressure.

However, it has been shown that the pressure, Pm , at which the oscillations have the

maximum amplitude, Am, is the mean arterial pressure (MAP). Empirical and theoretical

work has shown that the systolic and diastolic pressures, Ps and Pd respectively, occur when

the amplitudes of oscillation, As and Ad respectively, are a certain fraction of Am:

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Ps is the pressure above Pm at which As/Am = 0.55

Pd is the pressure below Pm at which Ad/Am = 0.85

Using this method, it is therefore possible to design a device for measuring Blood Pressure

noninvasively in which it is not necessary to analyse the Korotkoff sounds and only a cuff

needs to be attached to the patient.

2.3.3 MEASUREMENT PROCEDURE

Preparation for measurement

Before the blood pressure measurement begins the following conditions should be met:

1. Subjects should abstain from eating, drinking (anything else than water), smoking and

taking drugs that affect the blood pressure one hour before measurement.

2. Because a full bladder affects the blood pressure it should have been emptied.

3. Painful procedures and exercise should not have occurred within one hour.

4. Subject should have been sitting quietly for about 5 minutes.

5. Subject should have removed outer garments and all other tight clothes. The sleeve of

shirts, blouses, etc. should have been rolled up so that the upper right arm is bare. The

remaining garments should not be constrictive and the blood pressure cuff should not be

placed over the garment.

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6. Blood pressure should be measured in a quiet room with comfortable temperature. The

room temperature should have been recorded.

7. The time of day should have been recorded.

8. The blood pressure measurer should be identified on the blood pressure data recording

form.

Position of the subject

Measurements should be taken in sitting position so that the arm and back are supported.

Subject's feet should be resting firmly on the floor, not dangling. If the subject's feet do not

reach the floor, a platform should be used to support them.

Position of the arm

The measurements should be made on the right arm whenever possible. The subject's arm

should be resting on the desk so that the antecubital fossa (a triangular cavity of the elbow joint

that contains a tendon of the biceps, the median nerve, and the brachial artery) is at the level of

the heart and palm is facing up. To achieve this position, either the chair should be adjusted or

the arm on the desk should be raised, e.g. by using a pillow (see Figure 2 ). The subject must

always feel comfortable.

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Figure 2.2 : Position of the arm and placement of the cuff

Selection of the cuff

The greatest circumference of the upper arm is measured, with the arm relaxed and in the

normal blood pressure measurement position (antecubital fossa at the level of the heart), using a

non-elastic tape (see Figure 3). The measurement should be read to the nearest centimeter. This

reading should be recorded in the data form. Select the correct cuff for the arm circumference

and record the size of the selected cuff in the blood pressure recording data form. The cuff

should be placed on the right arm so that its bottom edge is 2-3 cm above the antecubital fossa,

allowing sufficient room for the bell of the stethoscope. The top edge of the cuff should not be

restricted by clothing.

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Figure 2.3 : Measurement of the arm circumference

2.3.4 BLOOD PRESSURE READING

Blood pressure rises with each heartbeat and falls when your heart relaxes

between beats. Blood pressure can change from minute to minute with changes in posture,

exercise, stress or sleep, it should normally be less than 120/80 mm Hg (less than 120 systolic

AND less than 80 diastolic) for an adult age 20 or over. A single high reading does not

necessarily mean that you have high blood pressure. However, if readings stay at 140/90 mm

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Hg or above (systolic 140 or above OR diastolic 90 or above) over time, your doctor will likely

want you to begin a treatment program. ( see Figure 4 ).

Figure 2.4 : Blood Pressure condition and Systolic/Diastolic reading

2.3 PRESENT WORK

The LED Blood Pressure Portable Monitor is a device that can measure users blood

pressure through an inflatable hand cuff. In this system, an inflatable hand cuff contains an

electronic pressure sensor that measures the air pressure. Using PIC18F2321 controller that

able to stimulate the measurement. The combination of hardware and PIC programming can be

determine of blood pressure reading that intergrated with pressure sensor. The element operates

in oscillometric principles gives the result in terms of systolic and diastolic. For more

32

preferable we convert the result into LED . Green LED indicates (pass) , Red LED indicates

(fail), while Yellow LED indicates (status) and lastly Clear LED indicates (power).

Figure 2.5 : LED Blood Pressure Portable Monitor

2.4 SUMMARY

To summarize, the differences between previous work and present work is the

LED, by using light people tend to be more alert and it was easy to understand as it is in

straight forward information. Its portable with a small size (6cm x 4cm x 2cm) and battery-

powered, making it great for areas with unreliable electricity. Its solid-state, so its tough and

reliable and doesnt contain mercury. And it detects high blood pressure automatically,

drastically reducing error .

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CHAPTER 3

METHODOLOGY

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3.1 INTRODUCTION

This chapter discuss about the block diagram,software development and also hardware

development.

3.2 BLOCK DIAGRAM

Figure 3.1 : Block diagram of LED Blood Pressure Portable Monitor

3.2.1 EXPLAINATION

The LED Blood Pressure Monitor consist of 5 distinct components :

1) MCU : Main component that controls all the operations such as motor and valve control,

A/D conversion, and calculation, until the measurement is completed (PIC18F2321 ).

2) MPX5050 : Pressure transducer to sense the pressure from the arm cuff.

3) LM324N : To amplify the signal for further processing.

4) LED : Emits visible light when an electric current passes through it.

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The capacitor and resistor used to remove the unwanted signal. Voltage regulator

LT1121CN8-3.3 used to maintain a constant output voltage even though its input voltage may

be highly variable.

3.3 HARDWARE AND SOFTWARE DEVELOPMENT

Flowchart of the projecrt :

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3.3.1 HARDWARE DEVELOPMENT

Below is the list of the entire electronic components and the other material that will

support to complete this project.

1. Sphygmomanometer with nylon cuff pre-gauged for adult arm size 10"16"

2. Batteries, NiCad, AA (3)

3. Battery holder, 3AA

4. Project box, approx. 6"4"2"

5. Knobs (2)

6. Wire, insulated, 2022 gauge, 24 gauge

7. Toggle switch, SPDT

8. Potentiometers, linear taper (2)

9. Wagan Micro Dynamo LED Flashlight Charger

10. Pressure sensor , 5V, 7mA, 6-pin MPX5050GP1

11. Microcontroller, Microchip PIC18F2321 Digi-Key #PIC18F2321-I/SP-ND

12. Voltage regulator IC, 8-pin Digi-Key #LT1121CN8-3.3

13. DIP sockets: , 8-pin (1), 14-pin (1), and 28-pin (1)

14. Op-amp IC, quad, LM324N

15. Resistors, 110k (2), 160k (3), 16k (2), 750k (2), 10k (1), 200 (4)

16. LEDs, 5mm, red (1), green (1), yellow (1), clear (1) ,Capacitors, 0.1F(1), 1F (6)

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Below is the list of the entire tools that will support to complete this project :

1. Saw

2. Marker

3. Soldering iron and solder

4. Wire cutter/stripper

5. Screwdrivers

6. Drill and drill bits 3.5mm, 5mm, 6mm, 7.75mm, 8mm

7. Hacksaw

8. Clamp

9. Label maker

3.3.2 PROJECT STEPS

1. Build the power supply on the breadboard.

Set up all the component on the breadboard. Add the voltage regulator. Place the 8-pin DIP

socket into the upper right of the circuit board and solder the connections .Solder a 1F

capacitor between pin 1 and ground. Solder a wire from pin 8, to be connected later to the

loose wire from the switch. Solder 2 wires to the circuit ground, for the crank ground wire an a

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battery ground wire. The figure of the component on the schematic diagram and on the

breadboard can be seen below :

Figure 3.2 : Schematic diagram of the component on bradboard

Figure 3.3 : All the electronic components on the breadboard

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2. Add the filters.

Figure 3.4 : Voltage regulator schematic diagram

Solder the 14-pin DIP socket onto the board as shown in Step 2, and add wires for power:

pin 4 goes to 3.3V and pin 11 goes to ground. If you use wire thicker than 22 gauge, you may

need a longer jumper on row 10 to go around the socket rather than under it. Build a 1.65V

reference voltage using op- amp 1 in the LM324 chip. Solder the two 110k resistors and the

0.1F capacitor. Connect op-amp 1s output to its own negative terminal.

Now add the smoothing filters and frequency components of the blood pressure sensor.

The sensors signal follows 2 forks: through a band-pass filter and a separate low-pass filter.

The band-pass filter consists of 2 high and low-pass filters, cascaded together. Make the first

high-pass filter by soldering a 1F capacitor in series with a 160k resistor. Connect the cap

to the pressure sensors output pin 1, and the resistor to the negative input of op-amp 3 Add

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gain to the circuit by soldering a 750k feedback resistor between op-amp 3s output and its

negative terminal.

Figure 3.5 : Pressure Sensor schematic diagram

Follow this with a low-pass filter: solder a 16k resistor from the output of op-amp 3 to

an open hole on the project board, and solder a 1F capacitor from this hole to ground. Feed

the output of the low-pass filter into a second high-pass filter made by placing a 1F capacitor

in series with a 160k resistor. Take the output of the second high-pass filter and feed it into

the negative terminal of op-amp 2. Add gain to the circuit by soldering a 750k resistor

between op-amp 2s output and its negative terminal. Take the output of the gain stage and

wire it to the input of a second low-pass filter: solder a 16k resistor from the output of op-

amp 2 to an open terminal hole, then solder a 1F capacitor from this hole to ground.

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Connect this filters output (VBandPass) to the microcontrollers pin 2 (analog input 0). Now

wire the separate low-pass filter: a 160k resistor from pressure sensor output pin 1 to an open

hole, and a 1F capacitor from this hole to ground. Connect this filters output (VLowPass) to

microcontroller pin 3 (analog input 1). Add the pressure sensor. Solder the pressure sensor in

the top left of the board and connect it .

3. Connect the microcontroller socket.

Figure 3.6 : PIC18F2321 microcontroller schematic diagram

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Solder the empty 28-pin DIP socket onto the project board, so its pin 1 is at the bottom.

Wire the connections, but dont plug in the microcontroller chip until youre done soldering.

Wire the power terminals: pins 8 and 19 go to ground, pin 20 goes to +3.3V. Wire the master

clear (pin 1) to +3.3V via a 10k pull-up resistor. For the LEDs, solder four 200 resistors to

pins 2124 of the. Solder leads to the LEDs and back to ground, as shown. The LED order is:

power (clear) on pin 21; status (yellow) pin 22; pass (green) pin 23; fail (red) pin 24. Connect

the pots, if the soldering feels cramped, you can use adjacent holes on the power and ground

traces.

4. Project Board Circuit (PCB)

Step :

i. Design using PCB wizard.

Figure 3.7 : PCB Board design

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ii. Print out the design onto the shiny side of the transfer paper.

Figure 3.8 : PCB on the transfer paper

iii. Sand the copper plate so there is a rough surface for the design to stick to when

transferred. Starting from this point on you should use surgical gloves to handle the

copper plate and etching solution, this helps avoid getting oils on the copper and

chemicals on your hands. When sanding do an extra good job on the edges.

iv. Run the copper plate with the design face down through an iron 5-7 minutes until the

plate is hot. After running the plate through an iron place the plate into a cold bath and

agitate until the paper floats off. Refer the image below :

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Figure 3.9 : Process of ironing the PCB

v. Place the PCB into the etching solution and agitate for 25-30 minutes or until all the

copper has dissolved around the design.

Figure 3.10 : PCB in the etching solution

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vi. Once all the copper is gone rinse it in the water bath, let it dry and use rubbing alcohol

to whip off the ink transfered onto the PCB.

Figure 3.11 : Drying the PCB

vii. And now you have a etched PCB board but you still need to drill the holes.

Figure 3.12 : Soldering all the component

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viii. Now. All the components have been solder on the PCB. The process are now complete.

Figure 3.13 : PCB process complete

5. Build the box

1. Drill the switch button.

2. Drill the LED button.

3. Put all the component on PCB inside the

casing.

4. Put the potentiometer,the LED and switch at

the right place.

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5. Project DONE.

Table 3.1 : Process of building the hand casing

3.3.3 SOFTWARE DEVELOPMENT

1. First start at the START state where the program waits for the user to push the switch

button of the device. Altogether the LED Yellow,Green,Red and Bkue will blinking to

show the device ON.

//-------------------------------LIGHT AND LEDS AND SETUP DEVICES------------------------ power = 0; thresh = 0; BPhigh = 0; BPgood = 0; setupTmrs(); //Make PORTA0 input for A/D converter TRISAbits.TRISA0 = 1; TRISAbits.TRISA1 = 1; TRISAbits.TRISA2 = 1; TRISAbits.TRISA3 = 1;

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//Set the ADC for internal RC clock ADCON2bits.ADCS2 = 1; ADCON2bits.ADCS1 = 1; ADCON2bits.ADCS0 = 1; ADCON0 = 0; //Set the ADC to use VDD and GND as references and AN0 - AN4 as A/D inputs ADCON1 = 0b00001010; //Delay 10000*4/32e3 = 1.25s Delay10KTCYx (20); //Turn off lights to save power thresh = 1; BPhigh = 1; BPgood = 1; //left justify ADC data ADCON2bits.ADFM = 1;

2. Once the switch button has been pushed,the measurememnt process begins by inflating

the hand cuff. If the cuff-inflating procedure goes smoothly,the air will be pumped into

the cuff until the pressure inside reaches 160 mmHg.

//--------------------------SAMPLE DIASTOLIC AND SYSTOLIC VALUES-------------------------- //Potentiometers on //pots = 0; //threshpot = 0; //Set the ADC to sample AN2 Diastolic value ADCON0bits.CHS3 = 0; ADCON0bits.CHS2 = 0; ADCON0bits.CHS1 = 1; ADCON0bits.CHS0 = 0; //Start conversion ADCON0bits.ADON = 1;

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ADCON0bits.GO = 1; Delay100TCYx (5); while (ADCON0bits.GO) ; ADCtemp = ADRES; BPdia_max = setDia(ADCtemp); //Set the ADC to sample AN3 Systolic value ADCON0bits.CHS3 = 0; ADCON0bits.CHS2 = 0; ADCON0bits.CHS1 = 1; ADCON0bits.CHS0 = 1; //Start conversion ADCON0bits.ADON = 1; ADCON0bits.GO = 1; Delay100TCYx (5); while (ADCON0bits.GO) ; ADCtemp = ADRES; BPsys_max = setSys(ADCtemp); BPmax = 160;

3. While the cuff is being inflated, once the pressure sensor reached the blood pressure of

our body it will light the LED Yellow indicates the STATUS received.

//potentiometers off //pots = 1; //threshpot = 1; //-------------------------------SWITCH OFF LEDS AND START ALGORITHM-------------------------- thresh = 1; BPgood = 1; BPhigh = 1; //Start conversion ADCON0bits.ADON = 1;

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4. After that the motor will be stopped and the air will be slowly released from the cuff. At

this point the MCU has obtained the values of systolic, diastolic and heart rate, the

valve will be open to release air from the cuff quickly.

while (1) { //Set ADC to channel AN0 ADCON0bits.CHS3 = 0; ADCON0bits.CHS2 = 0; ADCON0bits.CHS1 = 0; ADCON0bits.CHS0 = 0; Delay100TCYx (2); ADCON0bits.ADON = 1; ADCON0bits.GO = 1; Delay100TCYx (2); while (ADCON0bits.GO) ; BP = ADRES; //Set ADC to channel AN1 ADCON0bits.CHS3 = 0; ADCON0bits.CHS2 = 0; ADCON0bits.CHS1 = 0; ADCON0bits.CHS0 = 1; Delay100TCYx (2); ADCON0bits.ADON = 1; ADCON0bits.GO = 1; Delay100TCYx (2); while (ADCON0bits.GO) ; BPraw = ADRES; if (state == 0) { if(adc2press(BPraw) > BPmax+15) //start algorithm { thresh = 0; state = 1; BPhigh = 1; BPgood = 1; } else thresh = 1; } if (state == 1) { if(adc2press(BPraw) < BPmax) state = 2; }

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if (state == 2) { peaks(); if (adc2press(BPraw) < 55) state = 3; } if (state == 3) findBP(); } } void peaks(void) { #define offset 518 #define zero 509 //Find Peak if (BP>offset) //BP pulse bigger than threshold { BPhigh = 0; BPgood = 0; overthresh = 1; if (BP-zero>press[count]) { press[count] = BP-zero; raw[count] = adc2press(BPraw); } } else { BPhigh = 1; BPgood = 1; if (overthresh == 1) { overthresh = 0; count++; } } if (count == 40) { state = 3;//algorithm has finished } } void findBP(void) { char i = 0; char j = 0; #define Rsys 0.50 #define Rdia 0.85

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BPmap = 0; for (i = 1;iBPmap) { BPmap = press[i]; j = i; } } for (i=j;i>0;i--) { if ((press[i-1] Rsys*BPmap)) { //BPsys = raw[i-1]; BPsys = (unsigned char)(raw[i-1]-((Rsys*BPmap-press[i-1])/(press[i]-press[i-1]))*(raw[i-1]-raw[i])); } } for (i=j+1;i Rdia*BPmap)&(press[i] BPsys_max)||( BPdia > BPdia_max) ) { BPhigh = 0; BPgood = 1; } else { BPhigh = 1; BPgood = 0; } thresh = 1; Delay10KTCYx (2*del); BP = 0; BPraw = 0; BPsys = 0; BPdia = 0; BPmap = 0; count = 1;//Pressure index

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state = 0; overthresh = 0; for (i=0;i

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3.4 SUMMARY

To summarize , every project will have different methodologies that is being used

to make the project successful and working well. Generally, the methodologies are divided

into three parts, planning, reading, implementing, and analyzing. The planning phase there

including with reading activity and some job of requirements of hardware and software to be

used.

In reading activity we do research through several sources such as text books,

journal, paper references, the Internet and more sources due to get the information about the

project related. While in the requirements of hardware and software to be use we study and

find out the functional and operational of the hardware and software related.

Next step is implementing phase where in this part we produce the project circuit

board. When the PCB was ready to mount the electronic components, the process of

construction circuit is followed. The process of checking, testing and tuning are followed

due to complete a part of implementing.

Finally, in analysis phase we included the microcontroller program that manage to

run our LED Blood Pressure Portable Monitor project. With appropriate steps and

methodology, any process of completing the project can be managed wisely and will be

make a good result.

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CHAPTER 4

RESULT AND ANALYSIS

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4.1 INTRODUCTION

In this chapter we will discuss about the result and analysis for our project. Result is

the outcome, consequences or conclusion of a problem that we encountered during producing

the project. Every task and experiment in this project has the result to be discussed. this project

consist of testing the circuit, the connection between the pressure sensor MPX5050GP with the

microcontroller PIC18F2321. From the task that had been carried out, the result obtain for this

project are explained throughout this chapter.

4.2 RESULT

The results of the project are as expected and satisfactory to us. If the user stays still during the

operation, the device can measure blood pressures (pass or fail) without any problem.

1) Duration of measurement

From the start until all the measurements are done, it takes about 3 to 4 minutes. However,

this also depends on each individual and how the cuff is worn.

2) Accuracy

All the measurements are mainly dependent on the waveforms from the circuit and the

pressure sensor is very sensitive to even a slight movement of the user. As a result, it is possible

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that sometimes the device fails to obtain the desired data, especially if the user does not stay

still or wear the cuff improperly.

3) Usability

Our project should be useable to most adults. The instructions of LED are pretty straight

forward and easy to understand. The cuff that we use is appropriate for the average adult arm

size (9-13 inches in circumference). Thus the arm size that is out of this range may not give the

accurate measurement. For people with health problem, especially on blood pressure or heart, it

is not recommended to use this device, because we have only tested it with healthy people.

Therefore, for the maximum safety of the user, this device can only be used by the people who

do not have medical problems on heart and circulartory system.

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1. POWER ON

3. PASS

2. STATUS

4. STATUS COMPLETE

Table 4.1 : The result of the project

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4.3 ANALYSIS

4.3.1 PROBLEM ENCOUNTERED AND SOLUTION DEVELOPMENT

1) Amplitude of the blood pressure measurement

Regarding the two results, systolic and diastolic, some of them has more success rate than the

others. To find the pressure values are harder because they depend on the amplitude of the

waveform, and the amplitude varies a lot during the measurement. However, if the user stay

still and wears the cuff right, the measurement are usually successful.

2) Auscultotary method better than oscillometric method

The method of measurement is worth mentioning. It is usually deployed in commercial

products due to the reliability. However, this method is not as accurate as the auscultatory

method, in which the doctor uses the sthetoscope to listen to the noise in the artery.

3) Safety in design

( CUFF )

The cuff while driven by a 5 volts motor can squeeze the arm really hard and cause injury if

being used improperly. So in our device, we pump the cuff manually using the bulb, making

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sure that the operation can be detected by the user anytime once the Yellow LED light indicates

the status received.

(MICROCONTROLLER)

The microcontroller is programmed in the way such that if the pressure in the cuff is reaching

160 mmHg, the Yellow LED will light. For most people, the pressure at 160 mmHg will only

cause a little discomfort to the arm. This design make sure that the pressure inside the cuff will

never exceed the maximum limit of 160 mmHg.

4) Batteries and power consumption

Regarding batteries and power consumption, we encountered a big problem in this isssue while

testing the device, the jumper becomes hot instantly due to the excessive voltage run. At the

first place, we used one battery to power the MCU board and the other to power the circuit.

However after a couple of tries, the battery that powered the circuit lost its power and could not

provide a constant voltage during the measurement. In other words, the voltage across that

battery drops constantly as the motor runs. So we fixed this problem by covering the battery

with a proper casing that have it owns switch that runs the circuit and valve.

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5) LED and resistor

The resistor that we buy initially are wrong therefore some of the LED were not light up,

capacitor inside it burn due to the excessive current flow. Thus, we bought another value of

resistor to ensure the LED light properly.

4.4 SUMMARY

The summary for this chapter is, we completed the whole project successfully, from the

start until the end. Solve all the problem encountered during the whole process by getting an

advice from the supervisor and research, testing and analyse the performance consequently.

Thus, the project done completely without any disturbance.

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CHAPTER 5

CONCLUSION AND RECOMMENDATION

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5.1 CONCLUSION

In conclusion it is important to measure blood pressure because it is an important

measure of your health. This project design the small casing that can easy to bring anywhere. In

conclusion, the design and development of a LED Blood Pressure Portable Monitor device is

presented that it can measures the blood pressure range (pass or fail) efficiently in a short time

and with less expense without using time consuming and expensive clinical pulse detection

systems. By using analog signal processing techniques we can keep the device simple and to

efficiently suppress the disturbance in signals. The operation of the device are reliable and have

not produced any major problems except the delay for the result. All the component are put

together in one package which make the device portable.To summarize, simulations showed

that the blood pressure can be detected from an inflatable arm cuff contains an electronic

pressure sensor.

5.2 RECOMMENDATION

There are several recommendations for this project :

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1. Wireless Wrist Blood Pressure Monitor

Forget the wires and tubes. Improve the design by making it wireless and conducted it

on our wrist. This no hassle monitor makes it easy and convenient to check your own

blood pressure, anytime and anywhere.

2. Calculate the blood pressure using mobile Bluetooth Technology

Your systolic, diastolic and pulse rate get sent directly to your smartphone or tablet with

the help of Bluetooth technology. The easy-to-use mobile app saves a history of your

readings, plus its backed-up on the secure database at the mobile app so your data is

available to you on any computer, from wherever you are.

3. Measure. Track. Share.

The free app can be downloaded using Android or Apple automatically keeps a history

of your data and gives you the option to share your information with your doctor or

caregiver.

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REFERENCES

1. van Montfrans GA, Van Der Hoeven GMA, Karemaker JM, Wieling W, Dunning AJ.

Accuracy of auscultatory blood pressure measurement with a long cuff. Br Med

J. 1987;295:354-355.

2. Guidelines Sub-Committee. 1993 guidelines for the management of mild hypertension:

memorandum from a World Health Organization/International Society of Hypertension

meeting. J Hypertens. 1993;11:905-918.

3. The Joint National Committee on Detection, Evaluation, and Treatment of High Blood

Pressure. The Fifth Report of the Joint National Committee on Detection, Evaluation, and

Treatment of High Blood Pressure (JNC V). Arch Intern Med. 1993;153:154-183.

4. Staessen JA, Fagard R, Lijnen P, Thijs L, Van Hulle S, Vyncke G, Amery A.

Ambulatory blood pressure and blood pressure measured at home: progress report on a

population study. J Cardiovasc Pharmacol. 1994;23(suppl 5):S5-S11.

5. Mitchell PL, Parlin RW, Blackburn H. Effect of vertical displacement of the arm on

indirect blood-pressure measurement. N Engl J Med. 1964;271:72-74.

6. Schwan A, Pavek K. Change in posture during sleep causes errors in non-invasive

automatic blood pressure recordings. J Hypertens. 1989;7(suppl 6):S62-S63.

7. Di Rienzo M, Grassi G, Pedotti A, Mancia G. Continuous vs intermittent blood pressure

measurements in estimating 24-hour average blood pressure.Hypertension. 1983;5:264-

269.

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8. Parati G, Mutti E, Ravogli A, Trazzi S, Villani A, Mancia G. Advantages and

disadvantages of non-invasive ambulatory blood pressure monitoring. J Hypertens.

1990;8(suppl 6):S33-S38.

9. Bos WJW, van Goudoever J, van Montfrans GA, Wesseling KH. Influence of short-term

blood pressure variability on blood pressure determinations.Hypertension. 1992;19:606-

609.

10. Degaute JP, van de Borne P, Kerkhofs M, Dramaix M, Linkowski P. Does non-invasive

ambulatory blood pressure monitoring disturb sleep? J Hypertens. 1992;10:879-885.

11. Davies RJO, Jenkins NE, Strading JR. Effects of measuring ambulatory blood pressure

on sleep and on blood pressure during sleep. Br Med J.1994;308:820-823.

12. Staessen J, Bulpitt CJ, OBrien E, Cox J, Fagard R, Stanton A, Thijs L, Van Hulle S,

Vyncke G, Amery A. The diurnal blood pressure profile: a population study. Am J

Hypertens. 1992;5:386-392.

13. Prinze PN, Vitiello MV, Raskind MA, Thorpy MJ. Geriatrics: sleep disorders and

aging. N Engl J Med. 1990;323:520-525.

14. Veerman DP, van Montfrans GA, Wieling W. Effects of cuff inflation on self-recorded

blood pressure. Lancet. 1990;335:451-453.

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APPENDICES

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