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1. INTRODUCTION

A normal fetal heart rate (FHR) usually ranges from 120 to 160

beats per minute (bpm) in the utero period. At about 5 weeks gestation, your

baby's heart begins to beat. At this point, a normal fetal heart rate is about the same

heart rate as the mother's: about 80-85 beats per minute (BPM). It is measurable

sonographically from around 6 weeks and the normal range varies during

gestation, increasing to around 170 bpm at 10 weeks and decreasing from then to

around 130 bpm at term. From this point, it will increase its rate about 3 beats per

minute per day during that first month. By the beginning of the 9th week of

pregnancy, the normal fetal heart rate is an average of 175 BPM. At this point it

begins a rapid deceleration to the normal fetal heart rate for the middle of the

pregnancy of about 120-180 BPM. Fetal heart rate monitoring is used in nearly

every pregnancy at prenatal visits. It is done to check on how the fetus is doing and

to look for any problems. Fetal heart rate monitoring is especially helpful if you

have a high-risk pregnancy. The pregnancy will be high risk if the patient is an

diabetian or have high blood pressure. It is also high risk if the fetus is not

developing or growing thus the results of fetal heart rate monitoring will be less

accurate. Hence continuous monitoring can ensure the safe pregnancy for the

mother. MATLAB simulation is implemented to display the fetal heart rate. Here

the input signals are taken from the physionet website. This website provides the

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signals used for the research purposes. These signals are extracted as Matlab file.

Then by using the fuzzy logic these signals are trained and the fetal heart rate is

displayed in the LCD using Arduino.

Figure 1.1: Input signal

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2. BLOCK DIAGRAM

Figure 2.1: Block diagram

3. COMPONENTS

ARDUINO

LCD DISPLAY

MATERNAL

AND FETAL

SIGNAL

MATLAB

SOFTWA

RE

ARDUINO LCD

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4. HARDWARE DESCRIPTION

4.1 ARDUINO UNO

The Arduino Uno is a microcontroller board based on the

ATmega328. It has 14 digital input/output pins (of which 6 can be used as PWM

outputs), 6 analog inputs, a 16 MHz crystal oscillator, a USB connection, a power

jack, an ICSP header, and a reset button. It contains everything needed to support

the microcontroller. Simply connect it to a computer with a USB cable or power it

with a AC-to-DC adapter or battery to get started. The Uno differs from all

preceding boards in that it does not use the FTDI USB-to-serial driver chip.

Instead, it features the Atmega8U2 programmed as a USB-to-serial converter. All

Arduino boards are based around the ATMEGA AVR series microcontrollers from

ATMEL which feature both analog and digital pins. Arduino also created software

which is compatible with all Arduino microcontrollers. The software, also called

“Arduino”, it can be used to program any of the Arduino microcontrollers by

selecting them from a drop-down menu. Being open source and based around C,

Arduino users are not necessarily restricted to this software, and can use a variety

of other software to program the microcontrollers.

4.2 FEATURES

Operating Voltage 5V

Input Voltage (recommended) 7-12V

Input Voltage (limit) 6-20V

Digital I/O Pins 14 (of which 6 provide PWM output)

PWM Digital I/O Pins 6

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Analog Input Pins 6

DC Current per I/O Pin 20 mA

DC Current for 3.3V Pin 50 mA

Flash Memory 32 KB (ATmega328P) of which 0.5 KB used by bootloader

SRAM 2 KB (ATmega328P)

EEPROM 1 KB (ATmega328P)

Clock Speed 16 MHz

4.1.2 INPUT AND OUTPUT

Each of the 14 digital pins on the Uno can be used as an input or

output, using pinMode(), digitalWrite(), and digitalRead() functions. They operate

at 5 volts. Each pin can provide or receive 20 mA as recommended operating

condition and has an internal pull-up resistor (disconnected by default) of 20-50k

ohm. A maximum of 40mA is the value that must not be exceeded on any I/O pin

to avoid permanent damage to the microcontroller.

The Uno has 6 analog inputs, labeled A0 through A5, each of which

provide 10bits of resolution (i.e. 1024 different values). By default they measure

from ground to 5 volts, though is it possible to change the upper end of their range

using the AREF. pin and the analogReference() function.

There are a couple of other pins on the board:

AREF. Reference voltage for the analog inputs. Used with

analogReference().

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Reset. Bring this line LOW to reset the microcontroller. Typically used to

add a reset button to shields which block the one on the board.

Figure 4.1.1 Pin diagram

4.1.3 MEMORY

The ATmega328 has 32 KB (with 0.5 KB occupied by the bootloader).

It also has 2 KB of SRAM and 1 KB of EEPROM.

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4.1.4 POWER

The Uno board can be powered via the USB connection or with

an external power supply. The power source is selected automatically.

External (non-USB) power can come either from an AC-to-DC adapter (wall-wart)

or battery. The adapter can be connected by plugging a 2.1mm center-positive plug

into the board's power jack. Leads from a battery can be inserted in the GND and

Vin pin headers of the POWER connector.

The board can operate on an external supply from 6 to 20 volts.

If supplied with less than 7V, however, the 5V pin may supply less than five volts

and the board may become unstable. If using more than 12V, the voltage regulator

may overheat and damage the board. The recommended range is 7 to 12 volts.

The power pins are as follows:

Vin. The input voltage to the Uno board when it's using an external power

source (as opposed to 5 volts from the USB connection or other regulated

power source). You can supply voltage through this pin, or, if supplying

voltage via the power jack, access it through this pin.

5V.This pin outputs a regulated 5V from the regulator on the board. The

board can be supplied with power either from the DC power jack (7 - 12V),

the USB connector (5V), or the VIN pin of the board (7-12V). Supplying

voltage via the 5V or 3.3V pins bypasses the regulator, and can damage your

board. We don't advise it.

3V3. A 3.3 volt supply generated by the on-board regulator. Maximum

current draw is 50 mA.

GND. Ground pins.

IOREF. This pin on the Uno board provides the voltage reference with

which the microcontroller operates. A properly configured shield can read

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the IOREF pin voltage and select the appropriate power source or enable

voltage translators on the outputs to work with the 5V or 3.3V.

4.1.5 COMMUNICATION

The Uno has a number of facilities for communicating with a

computer, another Uno board, or other microcontrollers. The ATmega328 provides

UART TTL (5V) serial communication, which is available on digital pins 0 (RX)

and 1 (TX). An ATmega16U2 on the board channels this serial communication

over USB and appears as a virtual com port to software on the computer. The

16U2 firmware uses the standard USB COM drivers, and no external driver is

needed. The Arduino Software (IDE) includes a serial monitor which allows

simple textual data to be sent to and from the board. The RX and TX LEDs on the

board will flash when data is being transmitted via the USB-to-serial chip and USB

connection to the computer (but not for serial communication on pins 0 and 1). A

Software Serial library allows serial communication on any of the Uno's digital

pins.

The ATmega328 also supports I2C (TWI) and SPI

communication. The Arduino Software (IDE) includes a Wire library to simplify

use of the I2C bus; see the documentation for details. For SPI communication, use

the SPI library.

4.1.6 AUTOMATIC RESET

Rather than requiring a physical press of the reset button before

an upload, the Uno board is designed in a way that allows it to be reset by software

running on a connected computer. One of the hardware flow control lines (DTR) of

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the ATmega8U2/16U2 is connected to the reset line of the ATmega328 via a 100

nanofarad capacitor. When this line is asserted (taken low), the reset line drops

long enough to reset the chip. The Arduino Software (IDE) uses this capability to

allow you to upload code by simply pressing the upload button in the interface

toolbar. This means that the bootloader can have a shorter timeout, as the lowering

of DTR can be well-coordinated with the start of the upload.

This setup has other implications. When the Uno is connected

to either a computer running Mac OS X or Linux, it resets each time a connection

is made to it from software (via USB). For the following half-second or so, the

bootloader is running on the Uno. While it is programmed to ignore malformed

data (i.e. anything besides an upload of new code), it will intercept the first few

bytes of data sent to the board after a connection is opened. If a sketch running on

the board receives one-time configuration or other data when it first starts, make

sure that the software with which it communicates waits a second after opening the

connection and before sending this data.

The Uno board contains a trace that can be cut to disable the

auto-reset. The pads on either side of the trace can be soldered together to re-

enable it. It's labeled "RESET-EN". You may also be able to disable the auto-reset

by connecting a 110 ohm resistor from 5V to the reset line.

4.1.7 SPECIALIZED PIN FUNCTIONS

Some pins have specialized functions:

Serial: 0 (RX) and 1 (TX). Used to receive (RX) and transmit (TX) TTL

serial data. These pins are connected to the corresponding pins of the

ATmega8U2 USB-to-TTL Serial chip.

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External Interrupts: 2 and 3. These pins can be configured to trigger an

interrupt on a low value, a rising or falling edge, or a change in value. See

the attachInterrupt() function for details.

PWM: 3, 5, 6, 9, 10, and 11. Provide 8-bit PWM output with the

analogWrite() function.

SPI: 10 (SS), 11 (MOSI), 12 (MISO), 13 (SCK). These pins support SPI

communication using the SPI library.

LED: 13. There is a built-in LED driven by digital pin 13. When the pin is

HIGH value, the LED is on, when the pin is LOW, it's off.

TWI: A4 or SDA pin and A5 or SCL pin. Support TWI communication

using the Wire library.

4.1.8 PHYSICAL CHARACTERISTICS

The maximum length and width of the Uno PCB are 2.7 and 2.1 inches

respectively, with the USB connector and power jack extending beyond the former

dimension. Three screw holes allow the board to be attached to a surface or case.

Note that the distance between digital pins 7 and 8 is 160 mil (0.16"), not an even

multiple of the 100 mil spacing of the other pins.

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Figure 4.1.2 Physical characteristics

4.1.9 ADVANTAGES

Inexpensive

Cross-platform

Simple, clear programming environment

Open source and extensible software

Open source and extensible hardware

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4.2 LCD DISPLAY

A liquid crystal display (LCD) is a flat panel display,

electronic visual display, or video display that uses the light modulating properties

of liquid crystals. Liquid crystals (Fig 3.5) do not emit light directly. LCDs are

available to display arbitrary images (as in a general-purpose computer display) or

fixed images which can be displayed or hidden, such as preset words, digits, and 7-

segment displays as in a digital clock. They use the same basic technology, except

that arbitrary images are made up of a large number of small pixels, while other

displays have larger elements. LCDs are used in a wide range of applications

including computer monitors, televisions, instrument panels, aircraft cockpit

displays, and signage. They are common in consumer devices such as video

players, gaming devices, clocks, watches, calculators, and telephones, and have

replaced cathode ray tube (CRT) displays in most applications. They are available

in a wider range of screen sizes than CRT and plasma displays, and since they do

not use phosphors, they do not suffer image burn-in. LCDs are, however,

susceptible to image persistence. The LCD is more energy efficient and can be

disposed of more safely than a CRT. Its low electrical power consumption enables

it to be used in battery-powered electronic equipment. It is an electronically

modulated optical device made up of any number of segments filled with liquid

crystals and arrayed in front of a light source (backlight) or reflector to produce

images in color or monochrome. Liquid crystals were first developed in 1888. By

2008, worldwide sales of televisions with LCD screens exceeded annual sales of

CRT units; the CRT became obsolete for most purposes.

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Figure 4.2.1 LCD

4.2.1 PIN DESCRIPTION

The LCDs have a parallel interface, meaning that the

microcontroller has to manipulate several interface pins at once to control the

display. The interface consists of the following pins:

A register select (RS) pin that controls where in the LCD's

memory you're writing data to. You can select either the data register, which holds

what goes on the screen, or an instruction register, which is where the LCD's

controller looks for instructions on what to do next.

A Read/Write (R/W) pin that selects reading mode or writing mode

An Enable pin that enables writing to the registers

8 data pins (D0 -D7). The states of these pins (high or low) are the bits that you're

writing to a register when you write, or the values you're reading when you read.

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There's also a display constrast pin (Vo), power supply pins (+5V and Gnd) and

LED Backlight (Bklt+ and BKlt-) pins that you can use to power the LCD, control

the display contrast, and turn on and off the LED backlight, respectively.

4.2.2 PIN INTERFACING

To wire the LCD screen to arduino board, connect the following pins:

LCD RS pin to digital pin 12

LCD Enable pin to digital pin 11

LCD D4 pin to digital pin 5

LCD D5 pin to digital pin 4

LCD D6 pin to digital pin 3

LCD D7 pin to digital pin 2

Additionally, wire a 10k pot to +5V and GND, with it's wiper (output) to LCD

screens VO pin (pin3). A 220 ohm resistor is used to power the backlight of the

display, usually on pin 15 and 16 of the LCD connector

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Figure 4.2.2 Arduino and LCD interfacing

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Use of the LCD is pretty straightforward. After power-up, wait a

half second or so to let the LCD run its own initialization. Since the default mode

is eight bits, we’ll have to reinitialize it to accept our data via the four-bit bus.

When the four-bit initialization is complete, It can send our characters or

commands. The RS line is set high for characters, low for LCD commands.

The initialization code is required to allow the LCD to operate in

four-bit mode. After setting the four-bit interface, this section of code turns the

display on, turns off the underline cursor, and causes the cursor to increment after

each character is written. Just to ensure that there is no garbage left from any

previous operations, the Display Clear command is sent to the LCD.

Writing a character or command is done in these steps:

1. Set the RS line (HIGH for character, LOW for command).

2. Place the high nibble of the character/command byte on the bus.

3. Strobe the Enable line (cause a HIGH-to-LOW transition).

4. Place the low nibble on the bus.

5. Strobe the Enable line one more time.

The LCD pins are numbered from 1- 16 .In the case where the LCD is powered

with the Arduino by the 5V USB cable, selecting the contrast resistor to be 2K

ohm and the back LED resistor to be 100 ohm is a good start. Alternatively, a 5K

potentiometer can be used to adjust the contrast.

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Table 4.2.1 LCD and its interface

5 SOFTWARE DESCRIPTION

5.1 MATLAB SOFTWARE

MATLAB is a high-performance language for technical computing.

It integrates computation, visualization, and programming in an easy-to-use

environment where problems and solutions are expressed in familiar mathematical

notation. Typical uses include:

Math and computation

Algorithm development

Modeling, simulation, and prototyping

Data analysis, exploration, and visualization

Scientific and engineering graphics

Application development, including Graphical User Interface building

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The name MATLAB stands for matrix laboratory. MATLAB

features a family of application-specific solutions called toolboxes. Very important

to most users of MATLAB, toolboxes allow you to learn and apply specialized

technology. Toolboxes are comprehensive collections of MATLAB functions (M-

files) that extend the MATLAB environment to solve particular classes of

problems. Areas in which toolboxes are available include signal processing,

control systems, neural networks, fuzzy logic, wavelets, simulation, and many

others.

5.1.1 METHOD AND CONCEPT OF FECG EXTRACTION

The method used in this project is adaptive noise cancellation

(ANC) based on neuro fuzzy logic technique. ANC is a process by which the

interference signal can be filtered out by identifying a non linear model between a

measurable noise source (which is MECG in this case) and the corresponding

immeasurable interference. This is an extremely useful technique when a signal is

submerged in a very noisy environment. Usually, the MECG noise is not steady; it

changes from time to time. So the noise cancellation must be an adaptive process:

it should be able to work under changing conditions, and be able to adjust itself

according to the changing environment. The basic idea of an adaptive noise

cancellation algorithm is to pass the corrupted signal (abdominal) through a filter

that tends to suppress the MECG while leaving the signal unchanged. As

mentioned above, this is an adaptive process, which means it does not require prior

knowledge of signal or noise characteristics.

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Figure 5.1: Noise cancellation with ANFIS filtering

In this project, x(k) represents the FECG signal that is to be

extracted from the noisy signal. n(k) is the MECG which is the noise source signal.

The noise signal goes through an unknown nonlinear dynamics(f) and generates a

distorted d(k) which is then added to x(k) to form the measurable

output(abdominal) signal y(k).

During the extraction of the fetal heartbeat signal, the system

input parameters (of both the maternal and the fetal heartbeat signals) were

generated by codes written in matlab. These parameters were then passed to the

adaptive neuro fuzzy inference system (ANFIS) for training. In the process of

training, the parameters (i.e. membership function parameters) of each system

input signal continues to map each other until the adaptive noise canceller (ANC)

reaches a point of convergence. At this point the fetal heart rate signal is extracted.

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Figure 5.2:Flowchart for the extraction of FECG

5.1.2 ADVANTAGES OF ANFIS

Adaptive Neuro Fuzzy Inference System (ANFIS) was the

proposed technique for the extraction of Fetal Electrocardiogram (FECG) signals

from composite abdominal ECG recordings. The advantage of this technique over

other methods is that it requires only one abdominal signal and one thoracic signal.

But the other methods require many signals to validate their results. Compared to

other methods, ANFIS is well suitable for non linear applications. . Since this

technique uses neural network it requires fewer inputs to extract the FECG signal.

Convergence time is less compared to methods using neural network alone due to

the hybrid rule used in the ANFIS technique. ANFIS can separate the FECG

without dividing the signals into different frames. After removing the major

interference (MECG) from the FECG, it is easier to cancel the high frequency

noise using digital filters. Since the morphology of the extracted FECG using this

technique remains same, it can be used by the medical doctors and/or physicians to

diagnose.

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5.2 ARDUINO SOFTWARE

The open-source Arduino Software (IDE) makes it easy to

write code and upload it to the board. It runs on Windows, Mac OS X, and Linux.

The environment is written in Java and based on Processing and other open-source

software. This software can be used with any Arduino board. The Arduino

Integrated Development Environment or Arduino Software (IDE) contains a text

editor for writing code, a message area, a text console, a toolbar with buttons for

common functions and a series of menus. It connects to the Arduino and Genuino

hardware to upload programs and communicate with them.

Programs written using Arduino Software (IDE) are called

sketches. These sketches are written in the text editor and are saved with the file

extension .ino. The editor has features for cutting/pasting and for

searching/replacing text. The message area gives feedback while saving and

exporting and also displays errors. The console displays text output by the Arduino

Software (IDE), including complete error messages and other information. The

bottom righthand corner of the window displays the configured board and serial

port. The toolbar buttons allow you to verify and upload programs, create, open,

and save sketches, and open the serial monitor.

Verify/Compile

Checks your sketch for errors compiling it; it will report memory usage for

code and variables in the console area.

Upload

Compiles and loads the binary file onto the configured board through the

configured Port.

Upload Using Programmer : This will overwrite the bootloader on the board;

you will need to use Tools > Burn Bootloader to restore it and be able to

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Upload to USB serial port again. However, it allows you to use the full

capacity of the Flash memory for your sketch. Please note that this command

will NOT burn the fuses. To do so a Tools -> Burn Bootloader command

must be executed.

Export Compiled Binary : Saves a .hex file that may be kept as archive or

sent to the board using other tools.

Port

This menu contains all the serial devices (real or virtual) on your machine. It

should automatically refresh every time you open the top-level tools menu.

Burn Bootloader

The items in this menu allow you to burn a bootloader onto the

microcontroller on an Arduino board.

6.ADVANTAGES

Continuous fetal heart rate monitoring reduces the chances of

seizure after the birth, a symptom of brain injury from low oxygen. It also ensures

the well-being and safety of both mother and fetal during pregnancy.

An abnormal fetal heart rate or pattern mean that the fetus is not

getting enough oxygen or suffering from any other problems. If the fetal heart rate

lies above or below 120 to 160BPM, it indicates the emergency situation.

7.CONCLUSION

Thus the fetal heart rate is monitored by using the adaptive neuro

fuzzy logic which is implemented by MATLAB, in which the FECG signal is

extracted by comparing normal MECG signal from the MECG and the fetal heart

rate signal is displayed in the LCD using Arduino. So that we ensure the well-

being and safety of both mother and fetal during pregnancy.

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8. REFERENCE

[1] Assaleh K. (2007). Extraction of Fetal Electrocardiogram Using Adaptive

Neuro-Fuzzy Inference Systems, IEEE Trans. Biomed. Eng., 54: 59-68.

[2] Ibahimy M. et al. (2003). Real Time Signal Processing For Fetal Heart Rate

Monitoring, IEEE Med Biol. Eng. Comput., 50: 258-261.

[3] Jang J. (1993). ANFIS: Adaptive –Network- Based Fuzzy Inference

Systems, IEEE Trans. Syst. Man Cybern, 23: 665-683.

[4] Ferrara, E. R., and Widrow, B., “Fetal electrocardiogram enhancement by time-

sequenced adaptive filtering”, IEEE Trans. Biomed. Eng. 29,

pp. 458–460, 1982.

[5] Jafari, M. G., and Chambers, J. A., “Fetal electrocardiogram extraction by

sequential source separation in the wavelet domain”, IEEE

Transactions on Biomedical Engineering, vol. 52, no. 3, pp.390–400,2005.

[6] Widrow, B.,“Adaptive Noise Cancelling: Principles and Applications”,

Proc. IEEE, vol. 63, pp.1692-1716, Dec. 1975.

[7] John, R. G. Jr., “Adaptive Noise Canceling Applied to Sinusoidal

Interferences”, IEEE Trans. ASSP, Vol. ASSP-25, no. 6, pp. 484-491,

Dec.1977

[8] V. Zarzoso and A. Nandi, “Noninvasive fetal electrocardiogram extraction:

blind separation versus adaptive noise cancellation,” Biomedical Engineering,

IEEE Transactions on, vol. 48, no. 1, pp. 12–18, 2001.

[9] “Physionet, the research resource for complex biomedical signals.” http://www.

physionet.org/.

[10] R. Sameni and G. Clifford, “A review of fetal ECG signal processing; issues

and promising directions,” The open pacing, electrophysiology & therapy journal,

vol. 3, p. 4, 2010.