NOVEL DEVELOPMENT AND IMPLEMENTATION OF LOW POWER ECG MESUREMENT AND HEART RATE MONITOR FOR ELECTROCARDIOGRAM

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NOVEL DEVELOPMENT AND IMPLEMENTATION OF

LOW POWER ECG MESUREMENT AND HEART RATE

MONITOR FOR ELECTROCARDIOGRAM

PROJECT REPORT

PHASE -I

Submitted by

SEETHALAKSHMI P

Register No: 710012401015

in partial fulfillment for award of the degree

of

MASTER OF ENGINEERING

in

APPLIED ELECTRONICS

DEPARTMENT OF ELECTRONICS AND

COMMUNICATION ENGINEERING

ANNA UNIVERSITY

REGIONAL OFFICE, COIMBATORE

COIMBATORE-641047

DECEMBER 2013


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ANNA UNIVERSITY

REGIONAL OFFICE, COIMBATORE

COIMBATORE -641047.

Department of Electronics and Communication Engineering

PROJECT WORK

PHASE - I

DECEMBER 2013

This is to certify that the project entitled

is the bonafide record of project work done by

NOVEL DEVELOPMENT AND IMPLEMENTATION OF

LOW POWER ECG MESUREMENT AND HEART RATE

MONITOR FOR ELECTROCARDIOGRAM

SEETHALAKSHMI P

Register No: 710012401015

of M.E (APPLIED ELECTRONICS) during the year 2012-2014

---------------------------- ---------------------------

Dr.V.R.VIJAYKUMAR, M.E., Ph.D., Dr.R.VIJAYABHASKER, M.E., Ph.D.,

Head of the Department Project guide

Submitted for the project viva-voce examination held on_____________

------------------------ -----------------------Internal Examiner External Examiner


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ABSTRACT

Real-time monitoring of cardiac health is helpful for patients with

cardiovascular disease. Now a days the volume of Electrocardiogram (ECG)

recorded in hospitals is increasing as the people suffering from heart diseases

are increasing at an alarming rate. The ECG is one of the medical equipment

that can measure the heart rate, convert it into a signal and present the data on

a piece of paper or on a monitor. An ECG is a recording of the electrical

activity on the body surface generated by the heart. Many telemedicine

systems based on ubiquitous computing and communication techniques have

been proposed for monitoring the user's electrocardiogram (ECG) anywhere

and anytime. Usually, electrodes are used in these telemedicine systems.

However, electrodes require conduction gels and skin preparation that can be

inconvenient and uncomfortable for users and also requires more power.

In order to overcome this issue, a new novel for low power ECG

measurement is proposed and applied in developing in microcontroller for

various measurement of electrocardiogram signal on PC and heart rate is

displayed with the LCD.

The software tool used for this ECG and heart rate measurement is CC

studio 5.4v and oscilloscope with on PC and hardware kit is MSP430

Experimenter board.


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ACKNOWLEDGEMENT

First and foremost I place this project work on the feet of GOD

ALMIGHTY who is the power of strength in each step of progress towards the

successful completion of phase I project.

I would like to express my sense of profound gratitude and indebtedness to

Dr.R.VIJAYABHASKER, M.E., Ph.D., for his invaluable guidance,

suggestion and timely supervision for successful completion of the phase I project.

I am highly indebted to Dr.V.R.VIJAYKUMAR, BE., M.E., Ph.D.,Head

of the Department of ECE for providing invaluable insights into the subject and

helping me wherever possible.

I thank Dr.K.SARAVANA KUMAR, MBA., Ph.D., Dean-Campus Anna

University, Regional Office, and Coimbatore for his great support with blessings.

I also extend my heartfelt thanks to all staff membersof ECE Department

who have rendered their valuable help in making this project successful.

Above all I would like to thank all the members of my family and friends for

their constructive criticism and constant support in making this project a grand

success.

SEETHALAKSHMI P

Reg

No.:7100124101015

M.E APPLIED ELECTRONICS


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TABLE OF CONTENTS

CHAPTER NO. TITLE PAGE NO.

ABSTRACT Iii

LIST OF TABLES viii

LIST OF FIGURES ix

LIST OF ABBREVIATIONS[[ x

1 INTRODUCTION 1

1.1 OVERVIEW 1

1.2 OBJECTIVE OF THE WORK 2

1.3 MOTIVATION OF THE WORK 2

1.4 CHAPTER ORGANISATION 3

2 LITERATURE REVIEW 4

2.1 A WEARABLE MULTI PARAMETER MEDICAL

MONITORING AND ALERT SYSTEM4

2.2 BLUETOOTH TELEMEDICINE PROCESSOR FORMULTICHANNEL BIOMEDICAL SIGNAL

TRANSMISSION VIA MOBILE

4

2.3 A MOBILE CARE SYSTEM WITH ALERT

MECHANISM

5

2.4 A MULTICHANNEL PORTABLE ECG SYSTEM

WITH CAPACITIVE SENSORS

5

2.5 AN INTELLIGENT TELECARDIOLOGYSYSTEM

USING A WEARABLE AND WIRELESS ECG TO

DETECT ATRIAL FIBRILLATION

6

2.6 A SMART HEALTH MONITORING CHAIR FOR

NONINTRUSIVE MEASUREMENT OF

BIOLOGICAL SIGNALS

6


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3 HARDWARE DESCRIPTION 7

3.1 INTRODUCTION ABOUT MSP430

EXPERIMENTER BOARD

7

3.1.1 Board Features 8

3.2 MICROCONTROLLER BLOCK DIAGRAM 9

3.3 MSP430FG4618 SPECIFICATIONS 10

3.3.1 Peripherals 10

3.2.2 CPU 10

3.2.3 DMA controller 10

3.2.4 Oscillator and system clock 103.2.5 Brownout, Supply Voltage Supervisor 11

3.2.6 Digital I/O 12

3.2.7 Basic Timer1 and Real-Time Clock 12

3.2.8 LCD_A drive with regulated charge pump 12

3.2.9 Watchdog timer 13

3.2.10 Universal serial communication interface 13

3.2.11 USART1 13

3.2.12 Hardware multiplier 13

3.2.13 Timer_A3 14

3.2.14 Timer_B7 14

3.2.15 Comparator A 14

3.2.16 ADC12 14

3.2.17 DAC12 14

3.2.18 OA 15

3.4 PIN DIAGRAM AND DESCRIPTION 15

3.4.1 Pin Description 16

3.5 MSP 430FG4618 MICROCONTOLLER FEATURES 19

3.6 APPLICATIONS OF MSP430 20


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4 SYSTEM DESIGN AND IMPLEMENTATION 21

4.1 OVERVIEW 21

4.1.1 Introduction to ECG 21

4.1.2 Electrocardiographs 22

4.1.3 Fingertip capacitance 23

4.2 IMPLEMENTATION OF ECG MONITORING

SYSTEM

24

5 SIMULATION RESULTS AND DISSCUSSION 27

5.1 OVERVIEW OF THE SOFTWARE 27

5.1.1 Steps to execute the CC studio 285.2 CALCULATING THE HEART RATE 29

5.3 TESTING THE APPLICATION WITH CC STUDIO 30

5.4 HEART RATE MONITORING 30

5.5 PC SCOPE FOR ECG DISPLAY 32

6 CONCLUSION 33

6.1 FUTURE WORK 34

REFERENCES


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LIST OF TABLE

TABLE NO. TITLE PAGE NO

3.4.1 Pin description of MSP430FG4618 16


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LIST OF FIGURE

FIGURE NO. TITLE PAGE NO

3.1 MSP430 Experimenter Board 7

3.2 MSP430FG4618 Block diagram 9

3.4 Pin Diagram of MSP430FG4618 15

4.1.2 ECG waveform 22

4.1.3 Capacitive Sensing Plate 23

4.2 ECG Monitoring System 24

4.3 Complete Schematic of the Application 26

5.3 Execution of program 30

5.4 Snapshot of heart rate monitoring 31

5.5 PC Scope Program for ECG Display 32


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LIST OF ABBREVIATIONS

ACLK Auxiliary clock

ADC Analog to Digital Converter

ARM Advanced RISC Machine

ASIC Application Specific Integrated Circuits

BP Blood Pressure

CCS Code Composer Studio

CPU Central Processing Unit

DCO Digitally Controlled Oscillator

DMA Direct Memory Access

DSP Digital Signal Processor

ECG Electrocardiogram

FLL Frequency Locked Loop

GPRS Global Positioning Remote Sensing

HR Heart Rate

IDE Integrated Development Environment

I2C Inter Integrated Circuit

JTAG Joint Test Action Group

LCD Liquid Crystal Display

LED Light Emitting Diode

LF Liner Frequency

MCLK Main clock


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MCU Microcontroller

MI Myocardial infarction

MSP Mixed Signal Processor

MUX Multiplexer

OA Operational Amplifier

PC Personal Computer

PPG Photoplethysmograph

PWM Pulse Width Modulation

RAM Random Access Memory

RISC Reduced Instruction Set

RTC Real Time Clock

SMCLK Sub-Main clock

SPI Serial Programming Interface

SVS Supply Voltage Supervisor

SVM Supply Voltage Monitoring

USB FET Universal Serial Bus Flash Emulation

Tool

USCI Universal serial communication interface

UART Universal Asynchronous Receive Transmit

USART Universal Synchronous/Asynchronous

Receive Transmit

USI Universal Serial Interface

WDT Watch Dog Timer


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1

CHAPTER 1

INTRODUCTION

1.1 OVERVIEWNowadays, the volume of Electrocardiogram (ECG) recorded in

hospitals is increasing as the people suffering from heart diseases are

increasing at an alarming rate. The ECG is one of the medical equipment that

can measure the heart rate, convert it into a signal and present the data on a

piece of paper or on a monitor. An ECG is a recording of the electrical

activity on the body surface generated by the heart. ECG measurement

information is collected by electrodes placed at designated locations on the

body. It is the best way to measure and diagnose abnormal rhythms of the

heart [2] and [3], particularly abnormal rhythms caused by damage to the

conductive tissue that carries electrical signals, or abnormal rhythms caused

by electrolyte imbalances [4] and [7]. In a Myocardial infarction (MI), the

ECG can identify if the heart muscle has been damaged in specific areas,

though not all areas of the heart are covered [8] and [9]. The ECG cannot

reliably measure the pumping ability of the heart, for which ultrasound-based

(echocardiography) or nuclear medicine tests are used. It is possible to be in

cardiac arrest with a normal ECG signal (a condition known as pulse less

electrical activity). Electro-cardiogram (ECG) is [13] one of frequently used

and accurate methods for measuring the heart rate. ECG is an expensive

device and its use for the measurement of the heart rate only is not

economical. Low-cost devices in the form of wrist watches [20] are also

available for the instantaneous measurement of the heart rate. Such devices

can give accurate measurements but their cost is usually in excess of several

hundred dollars, making them uneconomical. Most hospitals and clinics in the

UK use integrated devices designed to measure the heart rate, blood pressure,


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and temperature of the subject. Although such devices are useful, their cost is

usually high and beyond the reach of individuals.

This paper describes the design of a low power ECG monitoring

system which monitors ECG and heart rate measurement system which

measures the heart rate of the subject by touching 4 symbols bythe arms and

then displaying the heart rate on Liquid Crystal Display (LCD) and the ECG

waveform is shown by oscilloscope software on the PC. The device has the

advantage that it is microcontroller based and thus can be programmed to

display various quantities, such as the normal, maximum and minimum ratesover a period of time and so on. Another advantage of such a design is that it

can be expanded and can easily be connected to a recording device or a PC to

collect and analyze the data for over a period of time.

1.2 MOTIVATION OF THE WORK

The motivation behind the project was the need for a small, portable

and ultra-low power wireless EEG recording system that is built from

commercially available electronic components, to help the research of animal

behavior and learning. There are many implementations of portable EEG and

ECG monitoring devices, but most of them were designed using special ASIC

or custom built integrated circuits. These were either never commercialized or

are far too expensive to be used in academic researches. This work is part of a

wider university project that was initiated to research the implications of in

brain activity. This thesis work aims to help support the heart rate

experiments by providing a necessary tool and lowering the research

expenses.

1.3 OBJECTIVES OF THE WORK

A novel low power ECG measurement was proposed in this study.

This application report describes how to build a digital heart-rate monitor


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using a MSP430FG4618 microcontroller (MCU). The heartbeat rate per

minute is displayed on an LCD. In addition, the application outputs a digital

data stream via an RS232 serial port to allow ECG waveform display on a PC.

The entire application runs using a CR2032 3-V lithium battery. The

experimental result presented that the low power ECG measurement performs

better for ECG measurement and heart rate, and is practicable for daily life

applications.

1.4 CHAPTER ORGANIZATION

The major objective of Phase-I project work is ECG implementation

and execution in target board. Chapters are organized as follows:

Chapter 1 Gives the brief introduction about ECG monitoringsystem and motivation and of the project.

Chapter 2 Describes and analyzes the previous works, related todifferent journals, IEEE standards and their drawbacks.

Chapter 3Discusses about the representation and the architectureof the hardware description of MSP430FG4618/F2013.

Chapter 4Discusses about the system design and implementationOF the ECG monitoring system.

Chapter 5Discusses about the simulation results.


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CHAPTER 2

LITERATURE SURVEY

2.1 A WEARABLE MULTI PARAMETER MEDICAL

MONITORING AND ALERT SYSTEM

In [24], U. Anliker et al, presents a development of a wearable

medical monitoring and alert system aimed at people at risk from heart and

respiratory disease. The system combines multi parameter measurement of

vital signs, online analysis and emergency detection, activity analysis and

cellular link to a telemedicine center in an unobtrusive wrist worn device. A

prototype of both the wrist device and the medical center software has been

implemented.

2.2 BLUETOOTH TELEMEDICINE PROCESSOR FOR

MULTICHANNEL BIOMEDICAL SIGNAL

TRANSMISSION VIA MOBILE CELLULAR NETWORKS

In [21], M. F. A. Rasid et al, states that the present scope and future

potential of mobile communications in telemedicine. A modular structured

GPRS based mobile system is presented to illustrate the concept. The unit

carried by the patient comprises a processing unit with a wireless connection

to a Bluetooth-enabled mobile telephone. The processor/telephone unit

accepts signals from up to four sets of sensors attached to the patient. The

prototype version is designed to transmit digitized signals to a hospital server

via the GPRS mobile telephone cellular network, which allows the

transmission of medical data as well as speech. As evidenced by the literature

outlined in Section I, the system is expected to become a powerful aid to

monitoring and diagnosis as well as a convenient means of communication.


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2.3 A MOBILE CARE SYSTEM WITH ALERT MECHANISM

In [13], R. G. Lee,et al, states that role-based mobile healthcare

system for chronic patients with an integration of multiple physiological

parameter extraction devices. For the personal mobile device construction as

the mobile healthcare system front-end, physiological parameter extraction

devices and mobile phones as personal mobile gateways were designed and

constructed separately. The separation in design leads to three major

advantages: high flexibility in architecture; good expandability in functions;

and simplicity in hardware design. By using mobile phones as integrationdevices and utilizing a program to design software modules with various

functions, personal mobile devices are not only powerful and flexible in

functions, but also provide a shortcut to the goal. It reduces both the time and

cost needed for system development.

2.4 A MULTICHANNEL PORTABLE ECG SYSTEM WITH

CAPACITIVE SENSORS

In [18], M. Oehleret al, illustrated that system based on capacitive

electrodes for measuring a multichannel ECG with a fixed sensor array. The

integration of the sensor array in a Tablet PC allows a very compact

affordable ECG system especially for easy access to the measurement of body

surface potential maps. The measurements were taken through clothes. No

ground contact is required to measure a multichannel ECG. The Tablet PC

provides a new, fast diagnostic tool through the real-time view of the

electrocardiogram without any preparation procedure.


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2.5 AN INTELLIGENT TELECARDIOLOGY SYSTEM USING A

WEARABLE AND WIRELESS ECG TO DETECT ATRIAL

FIBRILLATION

In [16], C. T. Lin, et al, demonstrates that the proposed intelligent

telecardiology system is capable of accurately detecting AF episodes and

instantaneously alerting both the user and the healthcare personnel,

facilitating early medical intervention. Furthermore, this intelligent

telecardiology system is superior to conventional healthcare devices because

it integrates all the key elements in one system. This novel system cannotonly be used for inpatients and outpatients, but also provides a long-lasting

health monitor to normal people. Patients wearing the lightweight three-limb

lead wireless ECG device can hardly feel its presence, but still enjoy a sense

of protection.

2.6 A SMART HEALTH MONITORING CHAIR FOR

NONINTRUSIVE MEASUREMENT OF BIOLOGICALSIGNALS

In [1], H. J. Baek et al, states that healthcare chair system may be

used to reliably monitor users during daily activities. Unlike conventional

medical devices, this system does not require active user input and is

therefore suitable for long-term daily health monitoring. Recent

improvements in biological signal recording through clothing enables many

applications for unconstrained biological signal monitoring in healthcare. By

integrating these technologies into a chair system, we successfully and

simultaneously measured ECG, PPG, and BCG through clothing in a

nonintrusive fashion. Continuous beat-to-beat HR and BP were also

successfully monitored using the obtained signals.


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CHAPTER 3

HARDWARE DESCRIPTION

3.1 INTRODUCTION ABOUT MSP430 EXPERIMENTER BOARD

This versatile MSP430 Experimenter Board features a MSP430F2013

and a MSP430FG4618 and is compatible with TIs wireless evaluation

modules. Two JTAG headers are accessible to program and debug each

MSP430 individually and allow for communication to external devices or

between the two MSP430s. Power may be supplied over the USB FET or

from the included AAA batteries.

Figure 3.1 MSP430 Experimenter Board

The combination of the tiny MSP430F2013 and the highly-integrated

MSP430FG4618 provides nearly every combination of peripherals available

from the MSP430 family. The integrated TI wireless evaluation module


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header and the large amounts of RAM on the MSP430FG4618 makes it an

ideal platform for wireless applications. The wide range of integrated

peripherals and hardware connectivity allows for nearly infinite development

possibilities and makes it the ideal learning platform the MSP430 MCU

architecture. A TI Flash Emulation Tool, like the MSP-FET430FUIF, is

required to program and debug the MSP430 devices on the experimenter

board.

3.1.1 BOARD Features

Mixed signal microprocessor 430 experimenter board has the

following feature in detail,

Devices Featured: MSP430FG4618, MSP430F2013 Integrated peripherals: 12-bit Digital-to-Analog Converter, 12-

bit SAR Analog-to-Digital Converter, 16-bit Sigma Delta

Analog-to-Digital Converter, Operational Amplifiers, DMA,

Multiplier, LCD Controller, Communication Interfaces: SPI,

UART, I2C, IrDA

Programming and Debugging: Can be programmed using anyMSP430 Flash Emulation Tool (MSP-FET430UIF)

Wireless expansion: Compatible with the following TI WirelessEvaluation Modules: CC1100, CC1101, CC1150, CC2500,CC2550, & CC2420

Board Features: Microphone, buzzer, LCD, capacitive touch-pad, 2x push buttons, prototyping space, RS232 communication

interface, 2x JTAG Programming Interfaces, 3.5mm headphone

jack (audio output)


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3.2 MICROCONTROLLER BLOCK DIAGRAM

MSP430 Experimenter Board has the microcontroller called

MSP430FG4618 .The figure 3.2 shows the internal block diagram that

explains various peripherals in the architecture of the microcontroller.

Figure3.2 MSP430FG4618 Block diagram

3.3 MSP430FG4618 SPECIFICATIONS

This section covers the specifications of the MSP430FG4618 mixed

signal microcontroller in detail. The architecture, combined with five low-

power modes, and is optimized to achieve extended battery life in portable

measurement applications. The digitally controlled oscillator (DCO) allows

wake-up from low-power modes to active mode in less than 1 s.


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3.3.1 Peripherals

Peripherals are connected to the CPU through data, address, and

control buses and can be handled using all instructions.

3.3.2 CPU

The MSP430 CPU has a 16-bit RISC architecture that is highly

transparent to the application. All operations, other than program-flow

instructions, are performed as register operations in conjunction with seven

addressing modes for source operand and four addressing modes fordestination operand. The CPU is integrated with 16 registers that provide

reduced instruction execution time. The register-to-register operation

execution time is one cycle of the CPU clock. Four of the registers, R0 to R3,

are dedicated as program counter, stack pointer, status register, and constant

generator respectively. The remaining registers are general-purpose registers.

Peripherals are connected to the CPU using data, address, and control buses,

and can be handled with all instructions.

3.3.3 DMA controller

The DMA controller allows movement of data from one memory

address to another without CPU intervention. For example, the DMA

controller can be used to move data from the ADC12 conversion memory to

RAM. Using the DMA controller can increase the throughput of peripheral

modules. The DMA controller reduces system power consumption by

allowing the CPU to remain in sleep mode without having to awaken to move

data to or from a peripheral.

3.3.4 Oscillator and system clock

The clock system in the MSP430xG461x family of devices is

supported by the FLL+ module, which includes support for a 32768-Hz watch


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crystal oscillator, an internal digitally controlled oscillator (DCO), and a high-

frequency crystal oscillator. The FLL+ clock module is designed to meet the

requirements of both low system cost and low power consumption. The FLL+

features digital frequency locked loop (FLL) hardware that, in conjunction

with a digital modulator, stabilizes the DCO frequency to a programmable

multiple of the watch crystal frequency. The internal DCO provides a fast

turn-on clock source and stabilizes in less than 6 s.

The FLL+ module provides the following clock signals:

Auxiliary clock (ACLK), sourced from a 32768-Hz watch crystal or ahigh frequency crystal

Main clock (MCLK), the system clock used by the CPU Sub-Main clock (SMCLK), the subsystem clock used by the

peripheral modules

ACLK/n, the buffered output of ACLK, ACLK/2, ACLK/4, orACLK/8

3.3.5 Brownout, Supply Voltage Supervisor

The brownout circuit is implemented to provide the proper internal

reset signal to the device during power-on and power-off. The supply voltage

supervisor (SVS) circuitry detects if the supply voltage drops below a user

selectable level and supports both supply voltage supervision (the device is

automatically reset) and supply voltage monitoring (SVM, the device is not

automatically reset).The CPU begins code execution after the brownout

circuit releases the device reset. However, VCC may not have ramped to VCC

(min) at that time. The user must insure the default FLL+ settings are not

changed until VCC reaches VCC (min). If desired, the SVS circuit can be

used to determine when VCC reaches VCC (min).


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3.3.6 Digital I/O

There are ten 8-bit I/O ports implementedports P1 through P10:

All individual I/O bits are independently programmable. Any combination of input, output, and interrupt conditions is

possible.

Edge-selectable interrupt input capability for all the eight bits of portsP1 and P2.

Read/write access to port-control registers is supported by allinstructions.

Ports P7/P8 and P9/P10 can be accessed word-wise as ports PA andPB respectively.

3.3.7 Basic Timer1 and Real-Time Clock

The Basic Timer1 has two independent 8-bit timers that can becascaded to form a 16-bit timer/counter. Both timers can be read and written

by software. Basic Timer1 is extended to provide an integrated real-time

clock (RTC).

3.3.8 LCD_A drive with regulated charge pump

The LCD_A driver generates the segment and common signals

required to drive an LCD display. The LCD_A controller has dedicated data

memory to hold segment drive information. Common and segment signals are

generated as defined by the mode. Static, 2-MUX, 3-MUX, and 4-MUX

LCDs are supported by this peripheral. The module can provide a LCD

voltage independent of the supply voltage with its integrated charge pump.

Furthermore it is possible to control the level of the LCD voltage and, thus,

contrast by software.


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3.3.9 Watchdog timer (WDT+)

The primary function of the WDT+ module is to perform a controlled

system restart after a software problem occurs. If the selected time interval

expires, a system reset is generated. If the watchdog function is not needed in

an application, the module can be configured as an interval timer and can

generate interrupts at selected time intervals.

3.3.10 Universal serial communication interface (USCI)

The USCI modules are used for serial data communication. The USCImodule supports synchronous communication protocols like SPI (3 or 4 pin),

I2C and asynchronous communication protocols like UART, enhanced UART

with automatic baud rate detection, and IrDA. The USCI_A0 module

provides support for SPI (3 or 4 pin), UART, enhanced UART and IrDA. The

USCI_B0 module provides support for SPI (3 or 4 pin) and I2C.

3.3.11 USART1

The hardware universal synchronous/asynchronous receive transmit

(USART) peripheral module is used for serial data communication. The

USART supports synchronous SPI (3 or 4 pin) and asynchronous UART

communication protocols, using double-buffered transmit and receive

channels.

3.3.12 Hardware multiplier

The multiplication operation is supported by a dedicated peripheral

module. The module performs 16_16, 16_8, 8_16, and 8_8 bit operations.

The module is capable of supporting signed and unsigned multiplication, as

well as signed and unsigned multiply and accumulates operations. The result

of an operation can be accessed immediately after the operands have been

loaded into the peripheral registers. No additional clock cycles are required.


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3.3.13 Timer_A3

Timer_A3 is a 16-bit timer/counter with three capture/compare

registers. Timer_A3 can support multiple capture/compares, PWM outputs,

and interval timing. Timer_A3 also has extensive interrupt capabilities.

Interrupts may be generated from the counter on overflow conditions and

from each of the capture/compare registers.

3.3.14 Timer_B7

Timer_B7 is a 16-bit timer/counter with seven capture/compareregisters. Timer_B7 can support multiple capture/compares, PWM outputs,

and interval timing. Timer_B7 also has extensive interrupt capabilities.

Interrupts may be generated from the counter on overflow conditions and

from each of the capture/compare registers.

3.3.15 Comparator_A

The primary function of the comparator A module is to support

precision slope analog-to-digital conversions, battery-voltage supervision, and

monitoring of external analog signals.

3.3.16 ADC12

The ADC12 module supports fast, 12-bit analog-to-digital

conversions. The module implements a 12-bit SAR core, sample selectcontrol, reference generator and a 16 word conversion-and-control buffer. The

conversion-and-control buffer allows up to 16 independent ADC samples to

be converted and stored without any CPU intervention.

3.3.17 DAC12

The DAC12 module is a 12-bit, R-ladder, voltage output DAC. The

DAC12 may be used in 8- or 12-bit mode, and may be used in conjunction


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with the DMA controller. When multiple DAC12 modules are present, they

may be grouped together for synchronous operation.

3.3.18 OA

The MSP430xG461x has three configurable low-current general-

purpose operational amplifiers. Each OA input and output terminal is

software-selectable and offer a flexible choice of connections for various

applications. The OA op amps primarily support front-end analog signal

conditioning prior to analog-to-digital conversion.

3.4 PIN DIAGRAM AND DESCRIPTION

The figure 3.4 shows the pin diagram of MSP430FG4618.The

controller as 100 pins with PDIP (plastic dual inline package) where the pins

protrude from the both ends of the IC package.

Figure 3.4 Pin Diagram of MSP430FG4618


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3.4.1 Pin description

The following table 3.4.1 shows the pin description of

MSP430FG4618 in detail.Table 3.4.1 pin description


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3.5 MSP 430FG4618 MICROCONTOLLER FEATURES

Ultra low power consumptiono Active mode :400 A at 1MHz , 2.2vo Standby mode : 1.3 Ao Off mode(ram retention) :0.22 A

Five power saving modes Low supply voltage range 1.8v to 3.6v Ultra-fast wakeup from standby mode in less than 6s 16-bit RISC architecture Basic clock module configuration

o Internal frequencies up to 16MHZ with one calibratedfrequency

o Internal very low power, low frequency (LF) oscillatoro 32 KHZ crystalo External digital clock source

16-bit timer A with two capture/compare registers Universal serial interface(USI) supporting SPI & I2C Brownout detector 12-bit A/D and dual D/A converter with internal reference


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Serial onboard programming On-chip emulation logic with spy-bi-wire interface 16-bit RISC architecture ,125ns instruction cycle time

3.6 APPLICATIONS OF MSP430

This section describes the following application as follows,

Portable medical meters, such as blood glucose meters, pulseoximeters

Insulin pumps

Digital thermometers Heart rate monitors Glass Break Detector Solar Power Inverters Telecom Shelter: Wireless Battery Monitoring
http://focus.ti.com/docs/solution/folders/print/489.htmlhttp://focus.ti.com/docs/solution/folders/print/349.htmlhttp://focus.ti.com/docs/solution/folders/print/603.htmlhttp://focus.ti.com/docs/solution/folders/print/603.htmlhttp://focus.ti.com/docs/solution/folders/print/349.htmlhttp://focus.ti.com/docs/solution/folders/print/489.html


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CHAPTER 4

SYSTEM DESIGN AND IMPLEMENTATION

4.1 OVERVIEW

In this chapter let us discuss about the implementation of this

application. The system comprises the modules like design of

electrocardiograph monitoring ECG circuit. Let us see about the

implementation of the systems in the following sections.

4.1.1 Introduction to ECG

Heart rate is one of the most frequently measured parameters of the

human body and plays an important role in determining an individuals

health. Heart rate measurement is becoming a part of the typical consumer

lifestyle, and many electronic devices such as iPods, exercise equipment, and

mobile phones are becoming able to accurately measure heart rate.

The following Methods used to measure heart rate

o Electrocardiographyo Photoplethysmographyo Oscillometry(Blood pressure monitor method)o Phonocardiography.

Each of these methods measures different phenomenon that occur in

human body during the heart beat or cardiac cycle to determine heart rate.

4.1.2 Electrocardiographs

The contraction and relaxation of cardiac muscles causes blood to

flow in and out of the heart. During each cardiac cycle, a group of tissue in

the heart called the sino atrial node (a.k.a., the pacemaker of heart) generates


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electrical impulses that spread all through the heart and cause rhythmic

contraction and relaxation of heart muscles. These electrical impulses can be

detected by placing electrodes in specific points in human body. An

electrocardiogram (ECG) captures this varying electrical impulse so shows

the overall rhythm of the heart.

This method requires placement of two or more electrodes on specific

points of the human body. The ECG signal is characterized by six peaks and

valleys labeled with successive letters of the alphabet: P, Q, R, S, T, and U

.The P-peak is produced by muscle contraction of the atria. The R-peak showsthe ending of atrial contraction and the beginning of ventricular contraction.

Finally, the T-peak marks the ending of a ventricular contraction. The

magnitude of the R-peak normally ranges from 0.1 mV to 1.5 mV.

Figure 4.1.2 ECG waveform

The average heart rate is calculated by first measuring the time

interval, denoted RR interval, between two consecutive R peaks and taking

the average reciprocal of this value over a fixed window, usually 15, 30 or 60


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seconds. This average is then scaled to units of beats per minute (bpm). R-

peak is a part of the RQS complex which represents ventricular

depolarization. Before calculating the heart rate, we must processing the ECG

in the analog (amplification, common mode voltages suppression and

filtering) and digital (digital filtering) domains. Most of these functions can

be performed by the microcontroller in real time.

4.1.3 Finger Touch Capacitance

Touch sensors have been around for years, but recent advances in

mixed signal programmable devices are making capacitance-based touch

sensors a practical and value-added alternative to mechanical switches in a

wide range of consumer products. This article walks through a design

example of a touch-sensitive button that can be actuated through a thick glass

overlay. The following figure 4.1.3 symbol 4 is used as a touch sensing pad in

MSP430 Experimenter board.

Figure 4.1.3Capacitive Sensing Plate

Typical capacitive sensor designs specify an overlay of 3mm or less.

Sensing a finger through an overlay becomes increasingly more difficult as


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the overlay thickness increases. In other words, as the overlay thickness

increases, the process of tuning the system moves from science to art. To

demonstrate how to make a capacitive sensor that pushes the limits of todays

technology, the thickness of the glass overlay in this example is set at 10mm.

Glass is easy to work with, readily available, and transparent so you can see

the underlying sensor pads. Glass overlays also have direct application in

white goods.

4.2 IMPLEMENTATION OF ECG MONITORING SYSTEM

The following section describes the entire application of block

diagram in detail. The ECG monitoring system diagram is shown in figure

4.2.

Figure 4.2 ECG Monitoring System

At the heart of any capacitive sensing system is a set of conductors

that interact with electric fields. The tissue of the human body is filled with


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conductive electrolytes covered by a layer of skin, a lossy dielectric. It is the

conductive property of fingers that makes capacitive touch sensing possible

.A simple parallel plate capacitor has two conductors separated by a dielectric

layer. Most of the energy in this system is concentrated directly between the

plates. Some of the energy spills over into the area outside the plates, and the

electric field lines associated with this effect are called fringing fields.

A parallel plate capacitor is not a good choice for such a sensor

pattern. Placing a finger near fringing electric fields adds conductive surface

area to the capacitive system. The additional charge storage capacity added by

the finger is known as finger capacitance, CF. The capacitance of the sensor

without a finger present is denoted as CF in this article, which stands for

parasitic capacitance. A common misconception about capacitive sensors is

that the finger needs to be grounded for the system to work. A finger can be

sensed because it can hold a charge, and this occurs if the finger is floating or

grounded.MSP is used as processor to control the flow of heart rate in human

body and LCD display is used to display the valve of heart rate signal for

every second. The pulse measures blood oxygenation by sensing the infrared

and red-light absorption properties of deoxygenated and oxygenated

hemoglobin. This comprised of a sensing probe that attaches to a patients

ear lobe, toe or finger and is connected to a data acquisition system for the

calculation and display of oxygen saturation level, heart rate and blood flow.

Power source to the controller is about only 3.3V .That is produced

by in built lithiyam AAA battery or from PC power. For mid-range and high-

end applications where higher performance and higher measurement accuracy

are necessary, there is a need for higher performance processors and high

precision analog components that provide lower system power. The complete

schematic application of ECG measurement system is shown in figure 4.3.


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Fig4.3 Complete Schematic of the Application


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CHAPTER 5

SIMULATIONS RESULTS AND DISSCUSSION

5.1 OVERVIEW OF THE SOFTWARE

The software used for ECG measurement and heart rate detection is

Code Composer Studio is an integrated development environment for

developing applications for Texas Instruments embedded processors. Texas

Instruments embedded processors include DSPs, ARM based devices and

other processors such as MSP430. Code Composer Studio includes a real time

operating system called DSP/BIOS or SYS/BIOS.

Code Composer Studio or CCS includes support for OS level

application debug as well as low-level JTAG based development. CCS is

based on the Eclipse open source software framework. Code Composer

Studio version 4 is based on a modified version of Eclipse. Code Composer

Studio version 5 uses an unmodified version of Eclipse, and also includes

support for Linux, as well as Microsoft Windows. Previous versions of CCS

used a proprietary IDE. Code Composer Studio (CC Studio) is an

integrated development environment (IDE) for Texas Instruments (TI)

embedded processor families. CC Studio comprises a suite of tools used to

develop and debug embedded applications. It includes compilers for each of

TI's device families, source code editor, project build environment, debugger,

profiler, simulators, real-time operating system and many other features.

The intuitive IDE provides a single user interface taking you through

each step of the application development flow. Familiar tools and interfaces

allow users to get started faster than ever before and add functionality to their

application thanks to sophisticated productivity tools.


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To install this version of Code Composer Studio(tm), follow these steps:

(1) Double-click on setup_CCS_4.2.1.xxxxx.zip

(2) On the menu bar, go to Actions -> Extract

(3) Select the directory where you wish to extract the files

(4) Select all of the following:

a. "All files/folders in archive"

b. Overwrite existing files

c. Use folder name

(5) De-select the following:

a. Open Explorer Window

b. Skip older files

(6) Click on Extract

(7) Once extraction has successfully completed, click onsetup_CCS_4.2.1.xxxxx.exe.

5.1.1 Step to execute the CC studio

The steps as follows

1.Create a new Project by selecting File New CCS Project.2.

Enter a project name, select "MSP430" as the Project Type and click

next until the Device Selection Page is shown. Select the Device

Variant used in the project.

3.Add the flashing LED code example to the project by clicking Project Add Files to Active Project... Code examples are located in

\msp430\examples\ according to the device

family that you are using.


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4.If using a USB Flash Emulation Tool such as the MSP-FET430UIFor the eZ430 Development Tool, they should be already configured

by default.

5.To compile the code and download the application to the targetdevice, go to Target Debug Active Project.

6.The application may be started by selecting Target Run (F8) orclicking the green Play button on the toolbar.

7.To terminate the debug session click go to Target Terminate All.5.2 CALCULATING THE HEARTBEAT RATE

The number of heart beats per minute is calculated using a three beat

average. Two variables in the C main function counter and pulse period,

accurately track the time scale. Each output sample from the QRS

discriminator is compared against a set threshold to detect the presence of a

beat. Pulse period is incremented by one during every sample period. Because

each sample occurs every 1/512 second, it is easy to track the time scale based

on the number of counts in the pulse period variable. A 128-sampleTime

window is used as a debounce time using counter. Every time a beat is

detected, counter is reset and the LCD icon with four arrows is turned on to

represent the heart beat. If a beat is not detected for 128 consecutive samples,

a separation between successive beats is identified and the LCD icon with

four arrows is turned off. The pulse period is accumulated for threeconsecutive beats. On the third beat, pulse period is used for the calculation of

heart-rate per minute and reset.

= 1/ [/ (3 512 60)]

= 92160/

5.3 TESTING THE APPLICATION WITH CC STUDIO


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The Figure 5.3 shows the execution level of the pulse are sensed by

using the Fingertip Capacitive touch sensors and it sends the message to the

MSP430 controller through LCD display.

Figure 5.3 Execution of program

5.4 HEART RATE MONITORING

At the heart of any capacitive sensing system is a set of conductors

that interact with electric fields. The tissue of the human body is filled with

conductive electrolytes covered by a layer of skin, a lossy dielectric. It is the

conductive property of fingers that makes capacitive touch sensing possible.

A simple parallel plate capacitor has two conductors separated by a dielectric

layer. Most of the energy in this system is concentrated directly between the


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plates. Some of the energy spills over into the area outside the plates, and the

electric field lines associated with this effect are called fringing fields.

Part of the challenge of making a practical capacitive sensor is to

design a set of printed circuit traces which direct fringing fields into an active

sensing area accessible to a user. A parallel plate capacitor is not a good

choice for such a sensor pattern. Placing a finger near fringing electric fields

adds conductive surface area to the capacitive system. The additional charge

storage capacity added by the finger is known as finger capacitance, CF. The

capacitance of the sensor without a finger present is denoted as CP in thisarticle, which stands for parasitic capacitance. A common misconception

about capacitive sensors is that the finger needs to be grounded for the system

to work. A finger can be sensed because it can hold a charge, and this occurs

if the finger is floating or grounded. The output of heart rate detection using

finger tip capacitance is shown in fig 5.4 the symbol 4 is used as touch

sensing.

Figure 5.4Snapshot of heart rate monitoring


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5.5 PC SCOPE FOR ECG DISPLAY

When using the "Heart rate with ECG Demo" program, an RS-232

level shifter is required between the ECG board and a PC. Only the TX

P4.0/UTXD1line is required, because no handshake is used for the serial

communication. The baud rate of the serial communication to the PC is 115.2

kbps. For displaying ECG, the PC must run scope.exe using command line

option of Windows. The scope.exe is an open source PC application program.

For convenience, this application program is provided in theoscilloscope.zip

file under the source files along with this application report .Figure 5.5 showsthe screen capture of the ECG display using the PC Scope application

program.

Figure 5.5 PC Scope Program for ECG Display

The following Figure5.5 shows the graph for the electrocardiograph

measures the heart beat rate in y axis and the time in x axis every second,

each ECG graph has the 6 intervals to measures the heart rate.


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CHAPTER 6

CONCLUSION

This work describes a prototype for a novel low power ECG

measurement is developed, fabricated, and experimentally validated in this

study. The focus of this thesis has been to design a compact ECG monitoring

device using commercially available electronic components. The project work

is presented starting with the objectives and the specifications that were laid

down. The following chapters then introduce the main building elements of

the designed circuit, and support the decisions that were made regarding

component selection. The layout of the monitoring device prototype was also

designed, taking into account the fabrication technology available in the

departmental work-shop. The dimensions of the board could therefore be

further reduced if the board manufacturing and component mounting steps

were to be carried out by professionals. The monitoring node was built on a

matrix breadboard, while the MSP430 Experimenter board from Texas

Instruments. The ECG signal quality acquired by using our low power ECG

measurement was consistent for all subjects, and the variation of ECG signal

quality is very stable, even under motion. Overall, our proposed low power

ECG measurement provides potential for routine and repetitive ECG

measurements, although its biocompatibilities still needed further validated.

This project was successfully implemented and the output of heart rate is

displayed on LCD and ECG waveform on the PC by using oscilloscope

software.


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6.1 FUTURE WORK

The project can be further developed in future by adding expert

system features like speed variations with moving screen, exact heart rate

with analysis, displaying 12 lead graphs, and monitoring ECG wave form on

PC monitor. We can enhance the feature of the project by enabling the

transmission of ECG signals through mobiles via wireless or Bluetooth.

This project can be further developed in future to monitor ECG signal

with different type of electrode.


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Documents

NOVEL DEVELOPMENT AND IMPLEMENTATION OF LOW POWER ECG MESUREMENT AND HEART RATE MONITOR FOR ELECTROCARDIOGRAM