This document presents the design and development of a portable system to simultaneously record seismocardiography (SCG) and electrocardiography (ECG) signals. The system aims to provide an affordable option for research and clinical use. It describes the motivation, objectives, hardware implementation, and signal analysis using MATLAB. Key aspects include using instrumentation amplifiers to measure SCG and ECG signals, active filters to preprocess the signals, and an Arduino with MATLAB for data collection and analysis. The document discusses the experimental process, limitations faced, and plans for future improvements to the system.

1. Paper ID: 230
Design and Development of a Portable Recording
System for Simultaneous Acquisition of SCG and
ECG Signals
Authored by
Tauhid Anwar, Mohammad Zubair, Mohammad Dehan Rahman, Nazmus Sakib, Md. Ahsan-Ul
Kabir, Tasnuva Faruk and Md Kafiul Islam
Presented by
Tauhid Anwar
Dept. of EEE, IUB
tauhid.chandan007@gmail.com
1
ICASERT 2019

2. Presentation
Outline
 Introduction
 Motivation & Objectives
 ECG and SCG basics
 Literature Review
 Proposed System Design
 Hardware Implementation
 Signal Analysis in MATLAB
 Limitation/Problem faced
 Conclusion
 Future Work
 Reference
2

3. Motivation and Objectives
Motivation :
 Increment of Death Rate due to Cardio Vascular
Disease (CVD) every year
 17.9 million people die each year from CVDs, an
estimated 31% of all deaths worldwide.
 >75% of CVD deaths occur in low-income and
middle-income countries and 85% are them
happened due to heart attacks and strokes.
 Effective and resource full features
Goal:
 Providing an affordable SCG & ECG system for
research purpose and clinical use.
Objectives :
 Design a low cost system that can be used for
measuring SCG and ECG signal simultaneously
 Making it as portable as possible .
>75%
In lower
income country
85%
Heart attacks and
Strokes.
17.9
Million people
die each year
3

4. SCG & ECG Basics …
Electrocardiography (ECG) is the term where electrical
functioning of the heart is studied. ECG is a standard
examination method in the clinical environment. ECG is
also feasible for use in remote monitoring.
Seismocardiography (SCG) is a non-invasive methods
for studying the mechanical vibrations that couple to the
body and produced by cardiovascular activity.
Seismocardiogram had considerable accuracy in the
identification of early coronary artery disease.
Notes :
• MC= Mitral (Valve) Closure
• A0 =Aortic (Valve) Opening
• RE = Rapid (Ventricu1ar)
Ejection
• MO = Mitral (Valve) Opening
• RF = Rapid (Ventricular) Filling
• AS =Atrial Systole
• AC =Aortic (Valve) Closure
• P wave
• PR interval
• QRS wave complex
• ST segment
• T wave
Figure: A typical resting seismocardiogram (SCG) and matching
electrocardiogram (ECG)
4

5. A Comparison of Non-invasive Cardiovascular
Assessment Methods5

6. Commercial High-end Machines
ECG Machine
SCG
Machine
6

7. Literature Review on Acquisition of SCG
 Existing Success in SCG Measurement
7

8. Proposed System
Isolation
Amplifie
r
Instrumentation
Amplifier(ECG)
Active
lowpass filter
Notch
filter
50/60 Hz
Active lowpass
filter
Patient Protection
Circuit
Instrumentation
Amplifier(SCG)
Notch filter
50/60 Hz
Dual DC Power
Supply
Adder
circuit
Adder
circuit
Single 5V
DC Power
Supply
Arduino PC/MATLABElectrodes
ECG& SCG
8

9. Electrodes
Using surface EKG/ECG electrodes
Permits electron conduction from the skin to the wire.
The connectors of these electrodes have three conductor
sensor cable with electrode pad leads.
Multi-useable electrodes, positive, negative and ground, to
the skin/surface covering the chest for better ECG signal
detection
Using piezoelectric sensors
Capture vibration from any surface
The positive(+) wire is connected in the middle of the
disc and negative (-) to the outer brass/copper plate.
Upper surface is well coted with piezo material
Such materials are - quartz single crystals. piezoelectric
ceramics, such as lithium niobate, gallium arsenide, zinc
oxide, aluminium nitride and lead zirconate-titanate
(PZT)
9

10. Instrumentation Amplifier for ECG
SPECIFICATIONS :
• Low cost, high accuracy with high
input impedance, low DC offset, low
noise and very high open-loop gain.
• High CMRR: >100dB
• Amplitude of input: 1mV to 10 mV.
• Gain = 1+
50𝑘𝞨
4.2𝐾
= 11.9
• Takes the difference between two
electrodes and amplify it.
10

11. Instrumentation Amplifier for SCG
SPECIFICATIONS :
• low bias current: ±4pa
• low quiescent current: ±450µa
• low input offset voltage: ±200µv
• low input offset drift: ±2µv/°c
• high cmr: 106db
• wide supply range: ±2.25v to ±18v
• Gain = 1+
50𝑘𝞨
1.48𝐾
= 33.7
• input protection to ±40v
11

12. Active Low-Pass Filter (ECG)
• Remove high frequency noise
interference.
• Cutoff Frequency:
1
2π R1R2C1C2
= 𝟖𝟐 𝐇𝐳
• Order of filter: 2nd order
• Gain: Unity
• Output: Non inverted
12

13. Active Low-Pass Filter (SCG)
• Remove high frequency noise interference.
• Cutoff Frequency:
1
2π R1R2C1C2
= 𝟏𝟓𝟎𝐇𝐳
• Order of filter: 10th order
• Gain: Unity
• Output: Non inverted
13

14. Active 50 Hz Notch Filter
 Filter type : Bandstop
 Filter response: Butterworth
 Filter order : 2
 Filter topology :Bainter
 Stopband attenuation: -45dB
 Center frequency : 50Hz
 Bandwidth: 3Hz.
14

15. Schematic of Whole System
15

16. Sensor Settings and Placement
16

17. Hardware Implementation
17

18. Experimental Setup
• For Experiment we chose 15 volunteer
• Subjects were healthy in physical form
• No previous heart disease
• Blood pressure was checked an found
normal
• No other disease was present at that
moment
• Subject was fully co-operative
• 3 type situation was created for
subjects. RESTING, WALKING,
CLIMBING STAIR .
18

19. Signal Analysis in MATLAB
19

20. 20
Signal Analysis in MATLAB (cont…)

21. Signal Analysis in MATLAB(cont…)
21

22. 22
Signal Analysis in MATLAB(cont…)

23. 23
Signal Analysis in MATLAB(cont…)

24. Cost Analysis
Name of
Equipment
Quantity Price (Taka)
AD620 1 450
INA121 1 700
Voltage
Regulator
4 60
OP177,LM 741 12 2400
Electrode
ECG&SCG
7 1640
Arduino uno 1 450
Resistor &
Capacitors
70+ 200
Belt, connecting
wire
100+ 200
Total 6100
 As there is no existing SCG
machine available in the market
so we couldn’t compare our
system cost with them .
 Cost can go higher if we use
quality sensor and ICs.
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25. Problem Faced/Limitations
 The whole process was not as easy as it looks .
 Took a lot of time to figure out what we have been actually looking for from theory
 Research papers doesn’t contain any kind of procedure or experimental setup that
can lead us how to do this project.
 Very limited amount of paper was present at this moment
 Sensors wasn’t available at the beginning of this experiment
 Used low and not efficient sensor at the beginning causing distorted and noise full
signal
 Took a lot of time to build the whole system as no previous system was present back
then
 No commercial device present at this moment to compare our result.
 We had to depend on research papers result and information that has been
recognized and accepted all over the world.
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26. Conclusion
 SCG can be a better complementary and useful diagnostic tool that can provide a lot better
and more information then single ECG diagnostic result.
 We have made a semi portable working system so that other researchers can do further
investigation and experiment on it.
 Cost can be reduce as we have a working model and basic structure for both ECG & SCG.
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27. Future work plan
 Create a new and improved version of our current system
 Convert the circuit to PCB
 Develop an algorithm that can automatically detect and point out impotent
parameters
 Improving sensor positions on chest.
 Improving the sensors for better detection of heart sound.
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28. References
• McKay, W. P. S., Gregson, P. H., McKay, B. W. S., & Militzer, J. (1999). Sternal acceleration
ballistocardiography and arterial pressure wave
• Lindqvist, A., Pihlajamäki, K., Jalonen, J., Laaksonen, V., & Alihanka, J.(1996). Static charge
sensitive bed ballistocardiography in cardiovascular monitoring. Clinical Physiology, 16(1),
23–30.
• Korhonen, I., Parkka, J., & Van Gils, M. (2003). Health monitoring in thehome of the future.
Engineering in Medicine and Biology Magazine, IEEE,22(3), 66–73.
• Khandpur, R. S. (2004). Biomedical instrumentation: Technology andapplications. McGraw-
Hill.
• Crow, R. S., Hannan, P., Jacobs, D., Hedquist, L., & Salerno, D. M. (1994).Relationship
between seismocardiogram and echocardiogram for events inthe cardiac cycle. American
Journal of Noninvasive Cardiology, 8(1), 39–46.
• Baevsky, R., Egorov, A., & Kazarian, L. (1964). Metodikaseismokardiografii. Kardiologiia,
18, 87–89.
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