ecg report_2014

Bluetooth Based Wireless ECG Monitoring System 2014

CHAPTER 1

1.1. INTRODUCTION

Mobile telemedicine systems are becoming more important all the time, especially in the care

of patients that are isolated or traveling, far from reference hospital. According to an

estimate, given by the World Health Organization (WHO), cardiovascular disease kills

almost seventeen million people around the globe each year along with twenty million people

at a risk of sudden heart failure. Some of these lives can often be saved if acute care and

cardiac surgery is provided within the so-called golden hour.

So the need for advice on first hand medical attention and promotion of good health by

patient monitoring and follow-up becomes inevitable. Hence, patients who are at risk require

that their cardiac health to be monitored frequently whether they are indoors or outdoors so

that emergency treatment is possible.

Telemedicine is widely considered to be part of the inevitable future of the modern practice

of medicine. Telemedicine can make available the benefits of new technologies, especially

information and communications, in providing medical care. These systems can be embedded

in low cost, small devices with low power consumption, and can have an interface that is

usable by the patient. Wireless technology [3] is to reduce the number of cables and wires

which may be tedious and often even hazardous.

Scientists and Engineers have been exerting, both a lot of time and money on these

technologies, and hence we have the beginning of what many are calling the Wireless Age.

Wireless technologies such as Bluetooth, GPRS, GSM or Wi-Fi to these systems allow the

wireless transmission to health or control centres.

Bluetooth and GSM/GPRS, and the development of software tools both for a computer and

for mobile devices enable a large range of application scenarios. Advantages of this are a low

cost, portable system with wireless transmission capabilities for the acquisition, processing,

storing and visualization in real time of the electrical activity of the heart to a mobile phone, a

PC.

One such place where wireless technology could be implemented is inside a hospital, where

there are several electrical devices using long wires and cables. An Electrocardiogram (ECG)

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Monitor which ideally has 12 cables connected to a patient could potentially be implemented

as a wireless system.

An ECG reading is proven worldwide to be the most accurate data used to determine a

patient’s heart condition. Therefore many studies have been focused in the design of a highly

intelligent, extremely friendly and easy to use, personal portable device for the early

detection and interpretation of ECG.

The wireless mobile healthcare system is a kind of flexible system that permits users real-

time monitor the important biological signals and transmits the analysis results to the remote

hospital central by mobile wireless communication device. The use of wireless

communication between mobile users has become increasingly popular due to the

advancements in computer and wireless technologies.

Implementation of wireless technology in the existing ECG monitoring system eliminates the

physical constraints imposed by hard-wired link and allows users to conduct own check up at

anytime anywhere. The usage of mobile phone has been recognized as a possible tool for

telemedicine since it has become a commercially available household article.

1.2. Electrocardiograms (ECG):

Electrocardiography (ECG or EKG) is a transthoracic interpretation of the electrical activity

of the heart over time captured and externally recorded by skin electrodes It is a non-invasive

recording produced by an electrocardiographic device. The etymology of the word is derived

from the Greek electro, because it is related to electrical activity, cardio, Greek for heart, and

graph, a Greek root meaning "to write".

The ECG works by detecting and amplifying the tiny electrical changes on the skin that are

caused when the heart muscle "depolarises" during each heart beat. At rest, each heart muscle

cell has a charge across its outer wall, or cell membrane. Reducing this charge towards zero is

called de-polarisation, which activates the mechanisms in the cell that cause it to contract.

During each heartbeat a healthy heart will have an orderly progression of a wave of

depolarisation that is triggered by the cells in the sinoatrial node, spreads out through the

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atrium passes through "intrinsic conduction pathways" and then spreads all over the

ventricles.

This is detected as tiny rises and falls in the voltage between two electrodes placed either side

of the heart which is displayed as a wavy line either on a screen or on paper. This display

indicates the overall rhythm of the heart and weaknesses in different parts of the heart

muscle.

An ECG is the recording of the heart electrical potential versus time [4]. In other words, an

ECG is simply an electrical recording of the heart. The ECG signal is used by the medical

profession in determining present or upcoming heart problems. ECG is among the most

commonly performed tests in medicine.

Fig1. Ideal ECG frame with typical features

ECG is characterized by a recurrent wave sequence of P, QRS and T- wave associated with

each beat. The QRS complex is the most striking waveform of all, caused by ventricular

depolarization and atrial re-polarization. Once the positions of the QRS complexes are found,

the locations of other waveforms of ECG like P, T waves and QT, ST segment etc. are found

relative to the position of QRS, in order to analyze the complete cardiac period.

An electrocardiogram is generated by a nerve impulse stimulus to a heart, whereby the

current is diffused around the surface of the body surface. The current at the body surface

will build on the voltage drop, which is a couple of µV to mV with an impulse variation. This

very small amplitude of impulse needs to be amplified to enable the recording and displaying.

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Usually, the electrocardiograph needs a couple of thousand times of amplification. ECG

signals The electrocardiograph is constructed to measure the electrical potential between

various points of the body. In a standard ECG recording there are five electrodes connected to

the patient:

1. Right arm, RA

2. Left arm, LA

3. Left leg, LL

4. Right Leg, RL

5. Chest, C

Depending how the electrodes pairs are connected to the ECG sensor different waveforms

and amplitudes can be obtained. Each pair contains unique information of the heart activity

that cannot be obtained from another pair of leads. Using real time ECG waveform data is a

good “stress test” for this transmission protocol.

With the increasing use of ECG Monitors, it is anticipated that such instruments will be used

in determining other health related issues. However, existing ECG monitoring systems are

relatively bulky and hence are less portable. This bulkiness is due to electronics involved in

obtaining high quality signals from the confounding effects of patient movement and

electrode attachment artefacts. Also, patients are confined to remaining near the ECG

Monitoring machine as they are attached to the ECG Monitor via the leads. The entire

process of obtaining ECG signals from Patients can be greatly eased with the use of portable

system that allows remote monitoring

1.3. Measuring ECG WavesElectrical waves cause the heart muscle to pump. These waves pass through the body

and can be measured by an array of electrodes (electrical contacts) attached to the

skin on specific parts of the body.

An ECG is constructed by measuring the electrical potential between these electrodes.

Although original ECGs consisted of 3 electrodes, modern ECGs usually consist of 7

to 12 electrodes. For the ECG senor designed and built for this project it was decided

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that 3 leads placed on both the right and left arm and one on the left foot (ground)

would be used. This is known as “Eindhoven’s triangle for electrode placement and

lead derivation”

Fig2.Lead Placement

1.4. Bluetooth Technology

Bluetooth is a wireless technology standard for exchanging data over short distances (using

short-wavelength UHF radio waves in the ISM band from 2.4 to 2.485 GHz) from fixed and

mobile devices, and building personal area networks (PANs). Invented by telecom

vendor Ericsson in 1994, it was originally conceived as a wireless alternative toRS-232 data

cables. It can connect several devices, overcoming problems of synchronization.

Bluetooth is managed by the Bluetooth Special Interest Group (SIG), which has more

than 19,000 member companies in the areas of telecommunication, computing,

networking, and consumer electronics.

Bluetooth was standardized as IEEE 802.15.1, but the standard is no longer

maintained.

5

http://en.wikipedia.org/wiki/Bluetooth_Special_Interest_Group

http://en.wikipedia.org/wiki/RS-232

http://en.wikipedia.org/wiki/Ericsson

http://en.wikipedia.org/wiki/Personal_area_network

http://en.wikipedia.org/wiki/ISM_band

http://en.wikipedia.org/wiki/Radio_waves

http://en.wikipedia.org/wiki/UHF

http://en.wikipedia.org/wiki/Wireless


The SIG oversees the development of the specification, manages the qualification

program, and protects the trademarks.

To be marketed as a Bluetooth device, it must be qualified to standards defined by

the SIG.

A network of patents is required to implement the technology, which is licensed only

for that qualifying device.

1.5. Implementation Bluetooth operates in the range of 2400–2483.5 MHz (including guard bands). This is

in the globally unlicensed (but not unregulated) Industrial, Scientific and Medical

(ISM) 2.4 GHz short-range radio frequency band.

Bluetooth uses a radio technology called frequency-hopping spread spectrum. The

transmitted data are divided into packets and each packet is transmitted on one of the

79 designated Bluetooth channels.

Each channel has a bandwidth of 1 MHz. Bluetooth 4.0 uses 2MHz spacing which

allows for 40 channels.

The first channel starts at 2402 MHz and continues up to 2480 MHz in 1 MHz steps.

It usually performs 1600 hops per second, with Adaptive Frequency-Hopping (AFH)

enabled.

Originally, Gaussian frequency-shift keying (GFSK) modulation was the only

modulation scheme available; subsequently, since the introduction of Bluetooth

2.0+EDR, π/4-DQPSK and 8DPSK modulation may also be used between compatible

devices.

Devices functioning with GFSK are said to be operating in basic rate (BR) mode

where an instantaneous data rate of 1 Mbit/s is possible.

The term Enhanced Data Rate (EDR) is used to describe π/4-DPSK and 8DPSK

schemes, each giving 2 and 3 Mbit/s respectively.

The combination of these (BR and EDR) modes in Bluetooth radio technology is

classified as a "BR/EDR radio".

Bluetooth is a packet-based protocol with a master-slave structure. One master may

communicate with up to seven slaves in a piconet; all devices share the master's clock.

Packet exchange is based on the basic clock, defined by the master, which ticks at

312.5 µs intervals.

6

http://en.wikipedia.org/wiki/Patent

http://en.wikipedia.org/wiki/Bluetooth_Special_Interest_Group#Qualification


Two clock ticks make up a slot of 625 µs; two slots make up a slot pair of 1250 µs.

In the simple case of single-slot packets the master transmits in even slots and

receives in odd slots; the slave, conversely, receives in even slots and transmits in odd

slots.

Packets may be 1, 3 or 5 slots long, but in all cases the master transmit will begin in

even slots and the slave transmit in odd slots.

1.6. Uses

Class

Max. permitted power Typ. range[13]

(m)(mW) (dBm)

1 100 20 ~100

2 2.5 4 ~10

3 1 0 ~1

Bluetooth is a standard wire-replacement communications protocol primarily

designed for low power consumption, with a short range based on low-

cost transceiver microchips in each device.

Because the devices use a radio (broadcast) communications system, they do not have

to be in visual line of sight of each other, however a quasi optical wireless path must

be viable.

Range is power-class-dependent, but effective ranges vary in practice; see the table on

the right.

Version Data rate Max. application throughput

1.2 1 Mbit/s >80 kbit/s

2.0 + EDR 3 Mbit/s >80 kbit/s

3.0 + HS 24 Mbit/s See Version 3.0 + HS

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4.0 24 Mbit/s See Version 4.0 LE

The effective range varies due to propagation conditions, material coverage,

production sample variations, antenna configurations and battery conditions.

Most Bluetooth applications are in indoor conditions, where attenuation of walls and

signal fading due to signal reflections will cause the range to be far lower than the

specified line-of-sight ranges of the Bluetooth products.

Most Bluetooth applications are battery powered Class 2 devices, with little difference

in range whether the other end of the link is a Class 1 or Class 2 device as the lower

powered device tends to set the range limit.

In some cases the effective range of the data link can be extended when a Class 2

devices is connecting to a Class 1 transceiver with both higher sensitivity and

transmission power than a typical Class 2 device.

Mostly however the Class 1 devices have a similar sensitivity to Class 2 devices.

Connecting two Class 1 devices with both high sensitivity and high power can allow

ranges far in excess of the typical 100m, depending on the throughput required by the

application.

Some such devices allow open field ranges of up to 1 km and beyond between two

similar devices without exceeding legal emission limits.

While the Bluetooth Core Specification does mandate minima for range, the range of

the technology is application specific and is not limited.

Manufacturers may tune their implementations to the range needed for individual use

cases.

Fig3. Bluetooth sign

1.7. Why Bluetooth

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IBM, Toshiba, and Intel formed a group to create a license-free technology for universal

wireless connectivity in the handheld market. The result is Bluetooth, a technology named

after a 10th-century king who brought warring Viking tribes under a common rule. The

Bluetooth specifications, currently in version define a radio frequency (RF) wireless

communication interface and the associated set of communication protocols.

Bluetooth standard offers important advantages

• low cost

• low EM interferences

• Reduced power consumption

• Confidentiality of the data

• It is embedded in most of portable, palm computers and mobile phones and already

used in a great number of wearable devices (e.g. mobile phones wireless headsets).

• Designed primarily as a cable replace technology, it enables ad-hoc wireless

networking, which allows formation of a network without base stations.

• The Bluetooth radio uses a low-powered transceiver that supports digital wireless

communications at the 2.4GHz ISM band allowing data rates of 721kbps.

• Bluetooth technology also provides fast, secure voice and data transmissions.

• Line of sight communication is not required.

• The Bluetooth radio unit functions even in noisy radio environments, ensuring audible

voice transmissions in severe conditions.

• Protects data by using error-correction methods.

• Provides a high transmission rate.

• Encrypts and authenticates for privacy.

1.8. Advantages

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• Low cost

• Portable system with wireless transmission

• Has capabilities for the acquisition, processing, storing and visualization in real time

of the electrical activity of the heart to a mobile phone, a PC.

• Reduced number of cables and wires as compared to the conventional monitoring

system which may be tedious and often even hazardous.

1.9. Disadvantages

• The size and the weight of the ECG amplifier .

• The ECG will be placed on the chest of the patient and should interfere as little as

possible with the patient’s mobility.

• The use of Bluetooth™ will limit the ECG-sensor system primary in the maximum

data rate of 750 kbps and the 10 meter range.

• The battery time for the PDA as well as the ECG sensor system.

CHAPTER 2

LITERATURE SURVEY

2.1 Bluetooth-enabled ECG Monitoring System

The mortality rate reported in government hospitals shows an increase in death due to heart

diseases, and this trend is expected to continue into the next decades. Since heart disease is

increasingly affecting human lifestyle, rehabilitation and practical devices are being carried

out and created in order to reduce the disability from heart diseases. This paper proposed a

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wireless patient monitoring system which integrates Bluetooth technology. In this paper, a

detailed description of constructing a 2-lead electrocardiogram (ECG) sensor, transmitting

the ECG data acquired from the ECG sensor via the Bluetooth wireless link, and receiving

the ECG data at the PC is illustrated. The acquired ECG data is processed, manipulated and

constructed as an ECG waveform. Lastly, the ECG waveform is displayed on the personal

computer (PC) screen. The results show that implementation of wireless technology in the

existing ECG monitoring system eliminates the physical constraints imposed by hard-wired

link and allows users to conduct own check-up at any time anywhere [1]

There have been different methods to develop a wireless ECG monitoring system where the

patient being examined is to be free of wires. The following methods use a slightly different

implementation in that electrodes are physically connected together, and then an ECG signal

is calculated. This processed data is transmitted wirelessly from the patient to a mobile base

station. The final implementation uses Bluetooth technology[2]

2.2. Heart Monitoring Of Clothed Person

The first implementation encountered during research used a completely different idea for a

wireless ECG monitor. It uses a completely wireless system where a heartbeat sensor was

devised that works without electrical connections to the patient.

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Fig 4.Monitoring the heart of a fully clothed person

2.3. FM Based ECG System

Another ECG system encountered is where several nodes are connected as a system (placed

on the patients chest) to calculate the patients ECG and relays this through the tissue of the

body (using FM modulation) to a transmitter located on the patients wrist and is transmitted

to a base station.

Fig5.ECG system

2.4. FM based ECG

This implementation obtains extremely low power consumption due to the method used for

signal transmission; however it suffers from the method of producing the ECG wave before

transmission.

2.5. Micromedical

Micromedical has also attempted to implement a wireless ECG monitor where a three node

system (as a single device) takes the ECG reading and is capable of connecting to a mobile

phone. The ECG wave is then transmitted to the treating Doctor. Although this

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implementation is not ideal for hospital situations, it can be used as general checkups for

patients in remote locations [3]

2.6. Bluetooth Based Solution

This system expands on a previously developed Internet based database which collects ECG

data from patients. The Bluetooth communications protocol is used in the system to send the

digitised ECG data to a WEB server via GSM phone modem [4]

2.7. BlueNurse

In this, Bluetooth wireless communications protocol is used to send an ECG signal from the

patient to mobile station (laptop). The architecture used for this implementation involved

using conventional ECG signal acquisition circuitry (ECG system) which measures and

filters an ECG signal with analogue circuitry before A/D converting). Also, the node meant

for transmitting the ECG signal consisted of three electrodes all of which returned to this

node. Still the system was unable to show an ECG reading of a patient wirelessly. That is, the

Bluetooth wireless link was functional; however the ECG application was not interfaced to

the communications link [5]

CHAPTER 3

3.1. PROBLEM STATEMENT

The problems faced by the conventional wired ECG which can be overcome by this project

are as follows

Conventional ECG consists of clusters of wires .However in this project the wires are

eliminated because of the wireless transmission of the signal.

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Normal ECG could not transmit the signal recorded from the patient’s body wirelessly. But

even this shortcoming has been overcome by using the Bluetooth module for wireless

transmission of the signal.

Previously, the patient had to be stationed next to the ECG system for recording his/her

cardiac signals. There was no portability. But here since Bluetooth is used the patient can

roam anywhere around the 10m range of the monitoring system.

Bluetooth technology is designed to have very low power consumption around 2.5mW.

Hence the power is drastically saved as compared to the conventional ECG’s.

Equipment cost is more since the circuitry is complex in conventional ECG’s .But the overall

cost of this project is very less because of the simplicity in the circuitry

More complex the circuitry more maintenance is required. However, here we are using very

simple circuitry which consists of a microcontroller, a Bluetooth module, a monitoring

terminal (Pc/laptop), few resistors and capacitors, voltage regulator, ECG leads etc. These

components hardly require any maintenance. But conventional ECG’s because of their

hardware complexity require time to time maintenance. Hence, even the maintenance issue is

solved.

CHAPTER 4

4.1. BLOCK DIAGRAM

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4.2. WORKING

Here the ECG patch cords attached to the patient’s body will detect the cardiovascular signals

and pass it on to the ECG circuit. The ECG circuit will amplify the received signal. It

converts it from a low level to a high level. This amplified signal is then given to the Atmega

168a microcontroller. The microcontroller brings about the analog to digital conversion of the

signal.

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The signal is then transmitted through the transmission port. And it is transmitted wirelessly

through the Bluetooth module.

The Bluetooth module then sends the signal to a remote terminal such as a laptop.

CHAPTER 5

SYSTEM ANALYSIS

Hardware Components

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5.1. Bluetooth Module HC-06

Description

This Bluetooth module can be used with any microcontroller. It uses the UART protocol to

make it easy to send and receive data wirelessly. The HC-06 module is a slave only device.

This means that it can connect to most phones and computers with Bluetooth but it cannot

connect to other slave only devices such as keyboards and other HC-06 modules. To connect

with other slave devices a master module would be necessary such as the HC-05 version

which can do both master and slave.

Features

A breakout board for easier connectivity

Designed for 3.3v level ttl but will accept 5v level as well

Built in antenna with a range of up to 30 feet (range is dependent on a lot of things

such as any obstacles or walls in the way so it may vary)

Supports baud rates from 1200 to 1382400 bps (default is 9600 bps)

VCC input voltage 3.3v to 6v

Bluetooth Specification v2.0+EDR

During the pairing, the current is fluctuant in the range of 30-40 m. The mean current

is about 25mA. After paring, no matter processing communication or not, the current

is 8mA. There is no sleep mode.

Diagram

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Fig6. Bluetooth module.

Pin Configuration

Fig7. Pin configuration.

5.2. Atmega 168a Microcontroller

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Description

The Atmel ATmega48/88/168a is a low-power CMOS 8-bit microcontroller based on the

AVR enhanced RISC architecture. By executing powerful instructions in a single clock cycle,

the ATmega48/88/168 achieves throughputs approaching 1 MIPS per MHz allowing the

system designer to optimize power consumption versus processing speed.

The AVR core combines a rich instruction set with 32 general purpose working registers. All

the 32 registers are directly connected to the Arithmetic Logic Unit (ALU), allowing two

independent registers to be accessed in one single instruction executed in one clock cycle.

The resulting architecture is more code efficient while achieving throughputs up to ten times

faster than conventional CISC microcontrollers.

Fig8. Atmega 168a Microcontroller

Features

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High performance, low power Atmel® AVR® 8-bit microcontroller

• Advanced RISC architecture

– 131 powerful instructions – most single clock cycle execution

– 32 × 8 general purpose working registers

• High endurance non-volatile memory segments

– 4/8/16 Kbytes of in-system self-programmable flash program memory

– 256/512/512 bytes EEPROM

– 512/1K/1Kbytes internal SRAM

• Peripheral features

– Two 8-bit timer/counters with separate prescaler and compare mode

– One 16-bit timer/counter with separate prescaler, compare mode, and capture mode

– Six PWM channels

– Programmable serial USART

– Master/slave SPI serial interface

– Programmable watchdog timer with separate on-chip oscillator

– On-chip analog comparator

• I/O and packages

– 23 programmable I/O lines

– 28-pin PDIP, 32-lead TQFP, 28-pad QFN/MLF and 32-pad QFN/MLF

• Operating voltage:

– 1.8V - 5.5V for Atmel ATmega48V/88V/168V

– 2.7V - 5.5V for Atmel ATmega48/88/168

Pin Configuration

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5.3. ECG Sensor

Description

An electrocardiogram – abbreviated as EKG or ECG – is a test that measures the electrical

activity of the heartbeat. With each beat, an electrical impulse (or wave) travels through the

heart. This wave causes the muscle to squeeze and pump blood from the heart. The EKG

(Electrocardiogram) sensor measures cardiac electrical potential waveforms (voltages

produced during contractions of the heart).The EKG sensor enables students to investigate

the electrical signals generated by the heart

The sensor consists of Fourier Systems plastic sensor case and three electrode leads. The

sensor comes with a package of one hundred silver/silver chloride electrode patches that can

be attached to the skin. The sensor's circuitry isolates the user from the possibility of

electrical shock.

Sensor Specification

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Range: 0 – 5 V

Resolution (12-bit): 1.23 mV

Recommended Sample Rate: 100 samples/sec

Voltage Protection: 4 kV

Isoelectric Line (Gain): 1mV body potential = 1V sensor out put

Maintenance: The electrodes should be kept refrigerated in a clean, dry, airtight

container for storage

5.4. ECG Electrodes Cable

Description

Diagram

Fig10. Cables

5.5. LM324 IC

Description

LM324 is a 14pin IC consisting of four independent operational amplifiers (op-amps)

compensated in a single package. Op-amps are high gain electronic voltage amplifier with

differential input and, usually, a single-ended output. The output voltage is many times higher

than the voltage difference between input terminals of an op-amp.

Pin configuration

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Features

• Eliminates need for dual supplies

• Four internally compensated op amps in a single package

• Allows directly sensing near GND and VOUT also goes to GND

• Compatible with all forms of logic

• Power drain suitable for battery operation

5.6. 7805 Voltage Regulator

Description

7805 is a voltage regulator integrated circuit. It is a member of 78xx series of fixed linear

voltage regulator ICs. The voltage source in a circuit may have fluctuations and would not

give the fixed voltage output. The voltage regulator IC maintains the output voltage at a

constant value. The xx in 78xx indicates the fixed output voltage it is designed to provide.

7805 provides +5V regulated power supply. Capacitors of suitable values can be connected at

input and output pins depending upon the respective voltage levels.

Pin Configuration

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Fig12. Pin out diagram

Features

3-Terminal Regulators

Output Current up to 1.5 A

Internal Thermal-Overload Protection

High Power-Dissipation Capability

Internal Short-Circuit Current Limiting

Output Transistor Safe-Area Compensation

5.7. Power Adaptor

An AC adapter, AC/DC adapter, or AC/DC converter[1] is a type of external power supply,

often enclosed in a case similar to an AC plug. Other names include plug pack, plug-in

adapter, adapter block, domestic mains adapter, line power adapter, wall wart, and power

adapter. Adapters for battery-powered equipment may be described as chargers or rechargers

(see also battery charger). AC adapters are used with electrical devices that require power but

do not contain internal components to derive the required voltage and power from mains

power. The internal circuitry of an external power supply is very similar to the design that

would be used for a built-in or internal supply.

External power supplies are used both with equipment with no other source of power and

with battery-powered equipment, where the supply, when plugged in, can sometimes charge

the battery in addition to powering the equipment.

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Use of an external power supply allows portability of equipment powered either by mains or

battery without the added bulk of internal power components, and makes it unnecessary to

produce equipment for use only with a specified power source; the same device can be

powered from 120Vac or 230Vac mains, vehicle or aircraft battery by using a different

adapter

Fig13. Adaptor

5.8. RS232 Connector

Description

RS-232 is a standard for serial communication transmission of data. It formally defined the

signals connecting between a DTE (data terminal equipment) such as a computer terminal,

and a DCE (data circuit-terminating equipment, originally defined as data communication

equipment[1]), such as a modem. The RS-232 standard is commonly used in computer serial

ports. The standard defines the electrical characteristics and timing of signals, the meaning of

signals, and the physical size and pinout of connectors.

25


Fig14. Rs232

Features

User data is sent as a time-series of bits.

Both synchronous and asynchronous transmissions are supported by the standard. In

addition to the data circuits, the standard defines a number of control circuits used to

manage the connection between the DTE and DCE.

Each data or control circuit only operates in one direction, that is, signalling from a

DTE to the attached DCE or the reverse.

Operates in a full duplex manner, supporting concurrent data flow in both directions.

The standard does not define character framing within the data stream, or character

encoding

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Applications

• DCE and DTE Devices

• 9 to 25 Pin Adapters

• Baud vs. Bits per Second

• Cables, Null Modems, and Gender Changers

• Cables Lengths

• Gender Changers

• Null Modem Cables and Null Modem Adaptors

• Synchronous and Asynchronous Communications

5.9. 100uf CAPACITOR

Description

Electrolytic decoupling capacitors 100uF/25V. These capacitors are great transient/surge

suppressors. Attach one between the power and ground of your project to ensure smooth

power delivery. High quality radial electrolytic capacitors. The 100uF cap (the bulk

capacitor) is primarily to support the supply during temporary battery disconnection during

physical shock

Fig15. capacitor

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5.10. Dc Power Jack

Description

A DC connector/jack (or DC plug, for one common type of connector) is an electrical

connector for supplying direct current (DC) power. Compared to domestic AC power plugs

and sockets, DC connectors have many more standard types that are not interchangeable. The

dimensions and arrangement of DC connectors can be chosen to prevent accidental

interconnection of incompatible sources and loads. Types vary from small coaxial connectors

used to power portable electronic devices from AC adapters, to connectors used for

automotive accessories and for battery packs in portable equipment.

Fig16. Power jack

5.11. LED (Power, TX, RX,)

A light-emitting diode (LED) is a two-lead semiconductor light source that resembles a basic

pn-junction diode, except that an LED also emits light.[7] When an LED's anode lead has a

voltage that is more positive than its cathode lead by at least the LED's forward voltage drop,

current flows. Electrons are able to recombine with holes within the device, releasing energy

in the form of photons. This effect is called electroluminescence, and the colour of the light

(corresponding to the energy of the photon) is determined by the energy band gap of the

semiconductor.

An LED is often small in area (less than 1 mm2), and integrated optical components may be

used to shape its radiation pattern

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Fig17. LED

5.12. 1nf CAPACITOR

A ceramic capacitor is a fixed value capacitor in which ceramic material acts as the dielectric.

It is constructed of two or more alternating layers of ceramic and a metal layer acting as

the electrodes. The composition of the ceramic material defines the electrical behaviour and

therefore applications. Ceramic capacitors are divided into two application classes:

Class 1 ceramic capacitors offer high stability and low losses for resonant circuit

applications.

Class 2 ceramic capacitors offer high volumetric efficiency for buffer, by-pass and

coupling applications.

Ceramic capacitors, especially the multilayer style (MLCC), are the most produced and used

capacitors in electronic equipment that incorporate approximately one trillion pieces (1000

billion pieces) per year.

Ceramic capacitors of special shapes and styles are used as capacitors

for RFI/EMI suppression, as feed-through capacitors and in larger dimensions as power

capacitors for transmitters

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Fig18. Capacitor

5.13 XLR Connector

The XLR connector is a style of electrical connector, primarily found on professional audio,

video, and stage lighting equipment. The connectors are circular in design and have between

3 and 7 pins. They are most commonly associated with balanced audio interconnection,

including AES3 digital audio, but are also used for lighting control, low-voltage power

supplies, and other applications. XLR connectors are available from a number of

manufacturers and are covered by an international standard for dimensions, IEC 61076-2-

103. They are superficially similar to the older and smaller DIN connect or range, but are not

physically compatible with them

5.14. Five pin

Five pin XLR connectors are the standard for DMX512 digital lighting control.

Other common uses are for dual-element or stereo microphones (two balanced audio signals

with a common ground) and stereo intercom headset (3 pins for the stereo headphone signal -

left, right, and ground, and 2 pins for the unbalanced microphone signal)

Fig19. Connector

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5.15. Epoxy Resin

FR-4 (or FR4) is a grade designation assigned to glass-reinforced epoxy laminate sheets,

tubes, rods and printed circuit boards (PCB). FR-4 is a composite material composed of

woven fiberglass cloth with an epoxy resin binder that is flame resistant (self-extinguishing).

"FR" stands for flame retardant, and denotes that safety of flammability of FR-4 is in

compliance with the standard UL94V-0. FR-4 is created from the constituent materials

(epoxy resin, woven glass fabric reinforcement, brominated flame retardant, etc.) by NEMA

in 1968.

FR-4 glass epoxy is a popular and versatile high-pressure thermoset plastic laminate grade

with good strength to weight ratios. With near zero water absorption, FR-4 is most commonly

used as an electrical insulator possessing considerable mechanical strength. The material is

known to retain its high mechanical values and electrical insulating qualities in both dry and

humid conditions. These attributes, along with good fabrication characteristics, lend utility to

this grade for a wide variety of electrical and mechanical applications.

NEMA is the regulating authority for FR-4 and other insulating laminate grades. Grade

designations for glass epoxy laminates are: G10, G11, FR4 and FR5. Of these, FR4 is the

grade most widely in use today. G-10, the predecessor to FR-4, lacks FR-4's self-

extinguishing flammability characteristics. Hence, FR-4 has since[when?] replaced G-10 in

most applications.

FR-4 epoxy resin systems typically employ bromine, a halogen, to facilitate flame-resistant

properties in FR-4 glass epoxy laminates. Some applications where thermal destruction of the

material is a desirable trait will still use G-10 non flame resistant.

Application

Printed circuit boards

FR-4 is the primary insulating backbone upon which the vast majority of rigid printed circuit

boards (PCBs) are produced. A thin layer of copper foil is laminated to one, or both sides of

an FR-4 glass epoxy panel. These are commonly referred to as "copper clad laminates."

31


FR-4 copper-clad sheets are fabricated with circuitry etched into copper layers to produce

printed circuit boards. More sophisticated and complex FR-4 printed circuit boards are

produced in multiple layers, also known as "multilayer circuitry".

FR-4 is also used in the construction of relays, switches, standoffs, bus bars, washers, arc

shields, transformers and screw terminal strips.

5.16. CIRCUIT DIAGRAM

Fig20. Circuit design

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Fig21. Bluetooth module

Fig22. ECG circuit

33


CHAPTER 6

6.1. Software Description

The Arduino integrated development environment (IDE) is a cross-platform application

written in Java, and is derived from the IDE for the Processing programming language and

the Wiring projects. It is designed to introduce programming to artists and other newcomers

unfamiliar with software development. It includes a code editor with features such as syntax

highlighting, brace matching, and automatic indentation, and is also capable of compiling and

uploading programs to the board with a single click. A program or code written for Arduino

is called a "sketch".

Arduino programs are written in C or C++. The Arduino IDE comes with a software library

called "Wiring" from the original Wiring project, which makes many common input/output

operations much easier. Users only need define two functions to make a runnable cyclic

executive program:

• setup(): a function run once at the start of a program that can initialize settings

• loop(): a function called repeatedly until the board powers off

A typical first program for a microcontroller simply blinks an LED on and off. In the Arduino

environment, the user might write a program like this:

The integrated pin 13 LED

#define LED_PIN 13

void setup (){pinMode(LED_PIN, OUTPUT);// Enable pin 13 for digital output}

void loop (){digitalWrite(LED_PIN, HIGH);// Turn on the LEDdelay(1000);// Wait one second (1000 milliseconds)digitalWrite(LED_PIN, LOW);// Turn off the LEDdelay(1000);// Wait one second}

34


Fig23. Arduino board

It is a feature of most Arduino boards that they have an LED and load resistor connected

between pin 13 and ground; a convenient feature for many simple tests.[16] The previous

code would not be seen by a standard C++ compiler as a valid program, so when the user

clicks the "Upload to I/O board" button in the IDE, a copy of the code is written to a

temporary file with an extra include header at the top and a very simple main() function at the

bottom, to make it a valid C++ program.

The Arduino IDE uses the GNU tool chain and AVR Libc to compile programs, and uses avr

dude to upload programs to the board.As the Arduino platform uses Atmel microcontrollers,

Atmel's development environment, AVR Studio or the newer Atmel Studio, may also be used

to develop software for the Arduino.

6.2 Arduino Bootloader for Atmega 168a

6.2.1. What is Arduino Bootloader

This is a bootloader. Basically the bootloader is a small piece of code that lets you run

Arduino code without any external hardware. So you could put the chip into an existing

project without an entire Arduino board.

6.2.2. How does it work

The "Burn Bootloader" commands in the Arduino environment use an open-source tool,

avrdude. There are four steps: unlocking the bootloader section of the chip, setting the the

fuses on the chip, uploading the bootloader code to the chip, and locking the bootloader

section of the chip. For the ATmega168, these are (where <BOARD> is either "diecimila" or

"ng"):

• bootloader.atmega168-<BOARD>.programmer (default value: avrispmkii) is the

protocal used by the bootloader.

35

http://en.wikipedia.org/wiki/File:Arduino_led-5.jpg


• bootloader.atmega168-<BOARD>.unlock_bits (default value: 0x3F) is the value to

write to the ATmega168 lock byte to unlock the bootloader section.

• bootloader.atmega168-<BOARD>.extended_fuses (default value: 0x00) is the value

to write to the high byte of the ATmega168 fuses.

• bootloader.atmega168-<BOARD>.high_fuses (default value: 0xdd) is the value to

write to the high byte of the ATmega168 fuses.

• bootloader.atmega168-<BOARD>.low_fuses (default value: 0xff) is the value to

write to the low byte of the ATmega168 fuses.

• bootloader.atmega168-<BOARD>.path (default value: bootloader168) is the path

(relative to the Arduino application directory) containing the precompiled bootloader.

• bootloader.atmega168-<BOARD>.file (default value:

ATmegaBOOT_168_<BOARD>.hex) is the name of the file containing the precompiled

bootloader code (in bootloader.path).

• bootloader.atmega168-<BOARD>.lock_bits (default value: 0x0F) is the value to

write to the ATmega168 lock byte to lock the bootloader section (so it doesn't get accidently

overwritten when you upload a sketch).

6.2.3. Burning Bootloader

To burn the bootloader, you'll need to buy an AVR-ISP (in-system programmer),

USBtinyISP or build a ParallelProgrammer. The programmer should be connected to the

ICSP pins (the 2 by 3 pin header) - make sure you plug it in the right way. The board must be

powered by an external power supply or the USB port.

Make sure you have the right item selected in the Tools | Board menu. Then, just launch the

appropriate command from the Tools > Burn Bootloader menu of the Arduino environment.

Burning the bootloader may take 15 seconds or more, so be patient.

36


6.3. Applications

• Xoscillo: open-source oscilloscope

• Scientific equipment

• Arduinome: a MIDI controller device that mimics the Monome

• OBDuino: a trip computer that uses the on-board diagnostics interface found in most

modern cars

• The Humane Reader and Humane PC from Humane Informatics: low-cost electronic

devices with TV-out that can hold a five thousand book library (e.g. offline Wikipedia

compilations) on a microSD card

• Ardupilot: drone software / hardware

• ArduinoPhone

37


6.4. Software Code

// these constants won’t change. They are used to give names

// to the pins used:

ConstintanalogInPin = A0: // analog input that the ECG is attached to

ConstintanalogoutPin = 9; // analog output pin that the LED is attached to

Intoutputvalue = 0; // value output (analog out)

Void setup() {

// read the analog in value:

Sensorvalue = analagRead(analogInpin);

//map it to the range of the analog out;

Output value = map (sensorvalue, 0, 1023, 0, 233 );

// change the analog out value;

Analogwrite(analogoutpin, outputvalue);

// print the results to the serial monitor;

Serial.print(“\t output = ’’);

Serial.printIn(outputvalue);

// wait 2 mili seconds before the next loop

//for thwanalog-to-digital converter to settle

//after the last reading;

Delay(2);

}

38


CHAPTER 7 PCB Designing

7.1. The UV-Exposure Method

7.1.1. Description:

For reproducible results when making PCBs and super-tiny structures, there is a UV-Device

for making PCBs now. Making PCBs with UV Exposure requires that some things are done

in a different way to when making them with the printer. This document should at some point

give an overview what steps are needed to make a pcb and what things you should be taken

care of.

Who may use the hardware

For a test, it was decided that there is an off limits project box behind the fridge. Only few

people may access it. It contains information on *who* that is. If you ask one of those people,

they will explain the process to you. This is for safety because you will have to use even

more chemicals than for pcb printing. If you access the box without permission, rage will

come upon you.

What is needed??

A foil to print on with the laserprinter (works good: Conrad / Laser-Spezial-Folie/matt Best.-

Nr.: 519570 - 62) 2. foto-positive base pcb-material (works good: Conrad / BungardPlatinen-

Basismaterial 120306E50 Best.-Nr.: 529184 - 62, 529273 - 62, 523683 – 62alternatively you

can use Butterbrotpapier and UV-Positiv-Lack (we even have that in the box with the uv

stuff) but it seems like a mess.

39


7.1.2. Safety hints precautions

You'll be working with quite some chemicals. Most of them are unhealthy for you.

You should at all times when touching anything wear gloves. Latex-Gloves stand in

the electronic lab.

Especially FeCl_3 will leave ugly spots on everything it touches. We have some

cleaner but it's a hazle and best is to not let anything get dirty. If you've got anything

on your gloves don't touch anything else with them. Pull them off, throw them away

and take new gloves.

If you touch chemicals by accident, don't panic. Go to the restroom immediately and

wash them off. It shouldn't be that bad.

If you've got injuries on your hands you should refrain from etching pcbs as you

might get the chemicals in the wounds.

The etching process takes some time, you should at least plan 2 hours (though it

shouldn't take more than 1.5 hours)

7.2. Procedural Steps

7.2.1. Print the positive

The first thing to do is printing the PCB layout to the foil. This can be done with the foil

named in (1) using the shack printer. Put the foil into the printer's manual feed face up (the

side that is marked to be sensitive to the toner facing up). It's recommended to fix a small part

of the foil to an A4 paper. Do not use gaffer tape or anything that melts because it will do so

in the printer and break the printer. Then print. You'll probably notice that the print looks

much more black compared to when you used *normal* paper. That is actually good. The foil

with the print on it will be called PRINTFOIL.

7.2.2. Prepare the UV-Exposure-Device

Open the device (it has two locks on the short sides).

40


Apply the PRINTFOIL to the glass surface. You might want to fix it with some tape.

Don't use Gaffa or normal TESA but something you can remove with as little residue

as possible. The PRINTFOIL side that contains the toner (and is thus darker) should

face up.

If the device seems dirty, don't do anything to clean itbut contact Armin / Leave him

a message. If you fail to comply, you're likely to be breaking the device.

7.2.3.Prepare the PCB

The PCBs come with some protective foil on them (the blue stuff in 2). Take it off on the side

you want to print on. Place the PCB on the PRINTFOIL so that the uv-coating points towards

the light source. Close the lid, fix it with the locks

7.2.4UV-Exposure for real

Set the device to the time you want to expose your PCB to light. The time should be 1

to 2 Minutes. If you have very fine structures, it's likely closer to 1 Minute than to 2

Minutes. For very large structure sizes, 3 Minutes is ok. It's a bit tricky to find out

the optimum time. I usually try 70 seconds at first. Works for SMD stuff like an

atmega 168 smduC.

You can find some values that worked below.

If you don't use the things (1) and (2) times may vary. Someone should make a lookup

table for that.

7.2.5 Fixing the PCB

Fixing is the process of hardening the part of the PCB that was not exposed to the UV

light and washing off the rest from the PCB. Use the white shell from the UV-PCB

Kit. Do never use this shell for anything else. The substance for fixing is Water and

Natriumhydroxide (NaOH) which makes Natronlauge. The amount to use for 1 litre is

7 grams of Natriumhydroxide. Since we use only about a quarter to an eight of a litre

of water, you should use 0.6 to 0.9 gram of Natriumhydroxide.

If you use too much, the fixing will completely wash off even the parts of the coating

that have not been in the light. If you don't use enough, nothing will happen.

41


It's not recommended to put more Natriumhydroxide into the bath while the PCB is

still in because it will result in places with ultra-high concentrations of

Natriumhydroxide that will instantly attach the coating that is supposed to harden.

The fixing should not take longer than 10 seconds to a minute. Sometimes you

already see the stuff after 2 seconds.

You'll see that your PCB structures that stay will become golden, while the rest

washes of and shows plain copper.

7.2.6.Etching the PCB

For etching we use FeCl_3

7.2.7 Washing off the PCB

Put a bit of Iso-propanol into a shelf (not the white one for the fixing substance,

remember?) and drop the pcb in it.

After a few seconds you should be able to wash the coating off. a greenish residue should

stay in the fluid. Take out the pcb and wash it off with water.

7.2.8 Finishing the PCB

Finish making the PCB by applying a layer of chemical tin to it

42


Fig24. UV Exposure Device

Fig25.PCB design

43


CHAPTER 8

8. Testing And Results

We tested our system by wiring two electrodes to the subject’s wrists, one on the right wrist

and one on the left wrist. The third electrode was placed on the subject’s right leg. The

subject was allowed to move freely within the radio range. The synchronization of the real-

time ECG and the motion information was displayed on the DSO(digital storage

oscilloscope).

Fig26. Signal output

44


Fig27. Signal output

45


CHAPTER 9

9.1. Conclusion

This system for Bluetooth based remote monitoring of medical condition in terms of

Electrocardiograph provides medics with information about cardiovascular conditions.

Getting accurate measures is of the utmost importance in such instances, especially if the

patient has history of heart disease. The doctor can monitor the medical condition of a

multiple number of patients at a time, from the convenience of his cabin.

This system has many advantages including efficiency, accuracy, and simplicity. It is very

suitable for ECG detection in clinical practice. A low cost system for ECG is used for

acquisition and visualization which is easy for a patient, as well as for a physician with little

previous knowledge.

Its design allows for easy technological updates and further development to provide more

intelligence to the system. Incorporating technologies such as Bluetooth, and the

development of software tools both for a computer and for mobile devices enables a large

range of application scenarios. Future research includes connection of the PC application to a

hospital database, and hardware processing of the ECG signal for automatic detection of

pathologies.

Given the prevalence of cardiac disease in India and the critical need for immediate treatment

for patients undergoing a cardiac emergency, any advancements in remote ECG monitoring is

likely to save lives.

46


9.2. Future Scope

Wireless monitoring of ECG keeps a check on the patient and helps the doctor know when

the patient is ill. ECG monitoring finds applications in professional healthcare sector and

consumer sector. Professional heath care sector involves applications like defibrillators,

automatic external defibrillators, holter monitor etc. Consumer sector includes commercial

fitness equipment, home products etc.

This system can be upgraded so that it is used in applications to monitor patients located in

remote places using wireless devices such as GPRS depending upon how far the patient is

located. According to the requirements of the patients, unique systems can be designed to

measure additional required biomedical parameters such as blood pressure, blood sugar,

temperature, heartbeat, ECG. Scaling down the system ensures that it is portable and the

patient can carry it with him wherever he goes.

47


REFERENCES

[1] Bin Yu and LishengXuYongxu Li “Bluetooth Low Energy (BLE) Based Mobile

Electrocardiogram Monitoring System” Proceeding of the IEEE International Conference on

Information and Automation Shenyang, China, pp 763-767, June 2012.

[2] Poonam T. Bedarkar ; Shanti Swamy “Bluetooth based visualization for real time ECG

monitoring”. Journal of Electrical, Electronics and Data Communication, ISSN (PRINT):

2320-2084, Volume – 1, Issue – 2, 2013

[3] ] http:// micromed.com/,micromedical

[4] R. Sukanesh, S. PalanivelRajan, S. Vijayprasath, S. JanardhanaPrabhu, P. Subathra, “

GSM-based ECG TelealertSystem” International Journal of Computer Science and

Application Issue 2010, ISSN 0974-0767, pp 112-116

[5]Bhavik Kumar Kant, "WIRELESS ECG”Volume III, University of Queensland Thesis,

2002.

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APPENDIX- I

Softcode Flow Chart

Infinite loop

Data

Transmitted

49

Start

Scan Analog port

Analog to digital conversion

Transmission through UART

Bluetooth

Delay of 2ms


50

Bluetooth

Start

Received signal at UART

Plot Graph

ecg report_2014

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