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International Journal of Engineering Trends and Technology ( IJETT ) Volume 61 Number 1 July 2018
ISSN: 2231 5381 Page 31
Design and Implementation of a Compact
Temperature, Heartbeat and ECG
Measurement Module
Jibesh Kanti Saha1, Shahadat Hussain Parvez2, Puja Rani Saha3
1Faculty, Dept. of EEE, Shahjalal University of Science and Technology, Sylhet-3114, Bangladesh.
2Faculty, Dept. of CSE, North East University Bangladesh, Sylhet-3110, Bangladesh.
1Faculty, Dept. of CSE, Leading University, Sylhet-3110, Bangladesh.
In this work we designed a user friendly
compact biomedical device that helps user to monitor
and record change in general vital signs like- body
temperature, heartbeat and ECG (electrocardiogram)
with simple digital sensor models. Conventional
biomedical devices are costly and requires expert
personnel to operate the device. This device was
designed to ensure portability, user-friendliness,
reliability, ease of maintenance and cost optimization.
The device also incorporates a computer interface
software which will show real time ECG graphs and
other measured biomedical data. This device can ensure
user-friendly patient monitoring and better
medication based on data statistics collected.
Keywords Biomedical Device, Patient
Monitoring, Real Time ECG, Body Temperature,
Heartbeat, Computer Interface, Biomedical sensors.
Day by day health conscious people are increasing
and they urge for frequent monitoring of their health
for a sound life. But this leads to exponential increase
in cost and hazards for ensuring care of general mass.
And in developing countries with less health care
facilities and practitioners in comparison with
popularity cannot cope up with this scenario.
Therefore, people are heading to cheap, reliable and
easily accessible health monitoring systems. This
golden era of electronics with its rapid advancement
opened up vast opportunities in this field. Measuring
instruments are also getting more compact and user
friendly. Newer and newer innovations are enriching
medical sectors greatly and this plays crucial role in
our civilization. Our work is a health monitoring
system with user friendly computer interface can
facilitate greatly as an easy household device. Such
remote patient monitoring framework is quite
common in technologically advanced countries in
different models like clinical monitoring, wearable
sensor network and so on [1]. These models save
huge time, money and hazards and also encourage
people to be more conscious of their own health.
Moreover, treatments with statistical data and
continuous monitoring can be achieved very easily
which helps different physicians deeply. In
developing countries such trend can have massive
impact on social and health development of general
The objectives of this project are to design and
implement a compact biomedical module facilitated
with computer interface which can measure basic
vital body signs like temperature, heart rate variability
and electrocardiogram. The data can be viewed in real
time via the interface both graphically and textually.
The whole model can be divided into four sections
shown in fig.1 below which are linearly connected
and dependent.
Fig. 1 System overview
A. Body Temperature Measurement
1) Background Study: Body temperature is one
of the oldest known diagnostic methods and is still a
vital sign of healthiness [1]. Variation from normal
temperature dictates disturbance in body system.
Body temperature is body's measurement of
generating and getting rid of heat. When heat rises the
blood vessels in skin widen to carry the excess heat to
skin's surface and helps cooling your body. Again,
when heat in body falls, blood vessels get narrower
and reduces blood flow to save body heat. Measuring
one‟s body temperature is an initial part of a full
clinical examination. Body‟s core temperature refers
to the thoracic and abdominal contents, some muscles
and brain, while the peripheral temperature relates to
a relatively small amount of subcutaneous tissue and
mostly the skin [2]. Generally, there exists thermal
gradient between the body surface and the deeper
tissues. It is seen that for each 4mm depth
temperature rises about 1°C approximately [3].
Specifically, the pulmonary artery (PA) measures the
temperature of mixed venous blood from the upper
and the lower parts of the body as well as the core and
International Journal of Engineering Trends and Technology ( IJETT ) Volume 61 Number 1 July 2018
ISSN: 2231 5381 Page 32
the periphery and so considered as the gold standard
of core temperature generally [4]. Usually in clinical
and household practice non-invasive methods are
popular [5].
2) Hardware: For measurement we used DS18B20
sensor which has a wide range of features other than
the popular use of temperature measurement. In this
sensor temperature measurements are made using two
bandgap-generated voltage sources. It senses
temperature by its unique 1-wire interface. Fig. 2
shows the waterproof model of DS18B20 sensor. In
final model temperature circuitry needs only these
following components:
DS18B20 Digital temperature sensor
Microcontroller (ATmega 328)
Resistor (4.7K)
Fig. 2 DS18B20 sensor
3) Process Flow: Heartbeat detection model is
implemented with different phase of actions. Fig. 3
illustrates the process flow comprising with the
subdivisions to implement the total thing.
Fig. 3 Process flow of Temperature measurement
4) Schematic: The following Fig. 4 is the
schematic diagram of the circuit designed for
temperature measurement.
Fig. 4 Temperature measurement circuit schematic
B. Heart Rate Measurement
1) Background Study: In 2005, WHO (World
Health Organization) reported that about seventeen
million people died in heart disease around the world
[6]. So, it is unquestionable that heart rate monitoring
has a great importance in patient monitoring. Heart
beat is a vital body sign which indicates the time
duration of a cardiac cycle. It is related to the
contraction of the muscles of the heart or a perceived
effect of it. As the heart pushes blood through the
arteries, the arteries expand and contract with the
flow of the blood. Resting heart rate means when
heart is pumping lowest amount of blood. It is usually
within 60 to 100 BPM according to many test-cites
[7]. Fast heart rate above 100 bpm at rest is defined as
Tachycardia [8]. Heartbeat of irregular pattern is
referred to as an arrhythmia. Heart rate pattern is
important because abnormalities of heart rate can
indicate different disease [9]. The heart rate monitor
can find several types of applications. Such as they
can be used in the hospitals, elderly health care,
personal emergency response or sport training [10].
Heart rate variability (HRV) is a special parameter
that can be measured during heart beat measurement.
While heart rate measures average beats per minute, it
measures the specific changes in time between
successive heart beats. HRV is generally measured in
milliseconds. HRV is best to measure at rest. At rest a
high HRV is generally preferable. Whereas in an
active state lower relative HRV is generally
The principle of operation is based on photoelectric
plethysmography. There are two types of
photoelectric plethysmography.
Transmission based
Reflection based
We used the reflection-based process.
Haemoglobin of blood can absorb a substantial
portion of light in our body and rest of them are
reflected from the body parts. In each cardiac cycle
blood concentration varies. This concentration
variation changes the amount of light reflected back
from the body parts. For our measurement we used
green light from a solid-state LED lamp instead of IR.
Green light has much less wavelength (about 525 nm)
than IR light as seen from the relative absorbance of
haemoglobin in Fig. 5 [11].
Fig. 5 Relative absorbance of hemoglobin
International Journal of Engineering Trends and Technology ( IJETT ) Volume 61 Number 1 July 2018
ISSN: 2231 5381 Page 33
2) Hardware: To implement the heartbeat
measuring circuitry we used following components.
SEN-11574 pulse sensor
Microcontroller (ATmega 328)
Low power Op-amp
Resistors and capacitors
SEN-11574 is integrated with a solid state green
LED and an ambient light photo sensor, which fits
our need.
3) Process Flow: Heartbeat detection model is
implemented with different phase of actions. The
process flow in the Fig. 6 shows the working process
of heartbeat measurement.
Fig. 5 Process flow of heartbeat detection
4) Schematic: There as three parts of the schematic
for the heartbeat measurement circuit as shown in Fig.
Fig. 6 Schematic of heartbeat measurement circuit
The first portion is named as „Capturing reflection‟.
With necessary circuitry there are a green led and a
photodetector. The light from the green led reflects
due to blood volume variation and photodetector gets
readings capturing the reflection. Photodetector
output comes with noise that is managed by the
filtering potion. The filtering portion is the second
part that comes with necessary circuitry named as
„Filtering part‟. The third and last part is „Amplifying
part‟. This section amplifies the processed filtered
output to a meaningful level. This output is feed to
microprocessor analog read. The further processing is
done through coding logics implemented according to
this reading.
C. Electrocardiogram (ECG)
1) Background Study: ECG is short form for
electrocardiogram or electrocardiograph, which is the
measurement process of heart‟s electrical activity, the
more appropriate term for which is the cardiac
conduction system. There are several ways to
measure ECG but mostly used and popular among
them is standard 12 lead ECG. In this method 12
electrodes are placed along chest, abdomen, hand and
leg and different signals are measured from these
electrodes. Besides the standard 12 lead ECG there
are several other methods in use [12].
3 channel ECG
5 channel ECG
Vector electrocardiography
Body surface mapping
In our thesis work we used a modified version of the
3-channel approach. This method is known as Wilson
electrode system combined with right leg driven
circuit. The right leg drive circuit works to reduce
interference from the amplifier. Amplifying an ECG
signal and creating a DC common mode bias off the
inputs of the differential amplifier causes extreme
susceptibility to common mode interference. Fig. 7
illustrates the right leg drive circuit [13].
Fig. 7 Right leg drive circuit
2) Hardware: The following components are used
for ECG measurement process:
AD8232 sensor
Microcontroller (ATmega 328)
ECG leads
AD8232 sensor is a single lead ECG front end with
common mode rejection ratio of 80 dB (dc to 60 Hz).
It works with two or three electrode configurations.
The integrated right leg drive amplifier is a major part
of this sensor. It also provides leads off detection both
for ac and dc. We used normal electrodes that are
used to measure such biopotential signals. These are
composed of a metal (usually silver for ECG
International Journal of Engineering Trends and Technology ( IJETT ) Volume 61 Number 1 July 2018
ISSN: 2231 5381 Page 34
measurement) and a salt of the metal (usually silver
chloride). Additionally, some form of electrode grade
or jelly is applied between the electrode and the skin.
3) Process Flow: ECG measurement needs several
phases to operate. In the process flow we have
subdivided the operations in simple three parts as
shown as Fig. 8 below.
Fig. 8 Process flow of ECG measurement
3) Schematic: Schematic circuit for ECG
measurement is shown in Fig 9.
Fig. 9 Schematic circuit of ECG detection
The RL, LA, RA connection are for electrode
placement. We used color coded ECG electrodes
where RL, LA and RA are attached to right leg, left
arm and right arm respectively.
The integrated system combines all the
measurement units together. With this major
integration there comes some other implementations
that paved the way to the final model.
We implemented a system interface for the project.
The interface has been developed by Processing
software. It incorporates following features:
A window for showing graphical change of
results over time. For special purpose two windows
are also used. Like implementing heartbeat
measurement one window shows the pulse variation
and a smaller one beside it shows inter beat interval
variation curve.
Mode selection option for switching to different
measurement. It is set as pressing „p‟ key goes to
previous mode and pressing „n‟ key takes to next
Each mode is presented as user understand the
state. Besides the name of the measurement a
graphical presentation is made to show on the
Computer port selecting options for
Snapshot of the window can be taken anytime
for storing the result curve by pressing „s‟ key.
Measurement result is averaged after a defined
time and average value is shown as a continuous
Styling of the interface can be modified through
coding for better look and feel. And other features or
controls can easily be integrated.
The interface is flexible to change it for
measuring a single parameter or some parameters
based on choice by some modification. This can help
to meet varieties of need of patients.
Fig. 10 Block diagram of the final prototype
After completion of the prototype, all the data
were measured on different subject to compare our
measurement with other conventional technique or
For temperature measurement waterproof
DS18B20 sensor was used. In the GUI the temperaure
was plotted to show the change of temperature over
time. The Fig.11 shows the comparision of our
temperature measurement with conventional mercury
thermometer and digital thermometer.
Fig. 11 Comparison of different temperature
International Journal of Engineering Trends and Technology ( IJETT ) Volume 61 Number 1 July 2018
ISSN: 2231 5381 Page 35
The graph in figure 12 below compares the heart
rate of 4 different subjects measured using our heart
rate sensor and by conventional manual method. For
heart rate measurement the GUI shows the pulse
variation with a smaller window showing inter beat
interval variation curve.
Fig. 12 Comparison of different Heart Rate
The three lead ECG used in our prototype is not
similar to traditional twelve lead ECG. Our goal was
to implement a simple system that will be easy to use
but will provide an useful data for quick diagnosis.
The figure 13 below shows how the GUI shows the
ECG wave.
Fig. 13 ECG data on the GUI
Rapid innovations in electronics and
biomedical field are revolutionizing the research
fields. These tacky devices are finding their path in
consumers market and making self-health monitoring
a common day‟s work for ordinary people. Our
designed module presents a new approach in health
monitoring. One of the main perk of our design is that,
the device is compact and integrable. It is very easy to
incorporate other forms of biomedical sensors with
our device. In future, this compact device will
incorporate sensors which will help to monitor and
record change in vital signs like- respiratory rate,
blood oxygen saturation, blood pressure etc. In near
future, compact heath monitoring devices like this
will revolutionize our everyday life.
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ResearchGate has not been able to resolve any citations for this publication.
Full-text available
Assessment of body temperature is important for decisions in nursing care, medical diagnosis, treatment and the need of laboratory tests. The definition of normal body temperature as 37°C was established in the middle of the 19th century. Since then the technical design and the accuracy of thermometers has been much improved. Knowledge of physical influence on the individual body temperature, such as thermoregulation and hormones, are still not taken into consideration in body temperature assessment. It is time for a change; the unadjusted mode should be used, without adjusting to another site and the same site of measurement should be used as far as possible. Peripheral sites, such as the axillary and the forehead site, are not recommended as an assessment of core body temperature in adults. Frail elderly individuals might have a low normal body temperature and therefore be at risk of being assessed as non-febrile. As the ear site is close to the hypothalamus and quickly responds to changes in the set point temperature, it is a preferable and recommendable site for measurement of body temperature.
Full-text available
This paper presents a current invention for monitoring the athletes' heart rate during training or exercise session. A bracelet with different color code of Light Emitting Diode (LED) is designed as a wrist heart rate monitor. This color-coding makes the heart rate easier to monitor and enabling the user to know their heart rate range at a certain moment. Our works investigate the used of Zigbee and ANT+ as a transmission medium from transmitter (chest strap) to receiver (bracelet). Different colors signify different ranges of heart rate. Preliminary result demonstrated that it is very helpful for athletes and coaches to monitor the fitness level of athletes and regulate their exercise training regime in a more effective and safer manner.
Full-text available
For the purpose of long-term, everyday electrocardiogram (ECG) monitoring, we present a convenient method of ECG measurement without direct conductive contact with the skin while subjects sat on a chair wearing normal clothes. Measurements were made using electrodes attached to the back of a chair, high-input-impedance amplifiers mounted on the electrodes, and a large ground-plane placed on the chair seat. ECGs were obtained by the presented method for several types of clothing and compared to ECGs obtained from conventional measurement using Ag-AgCl electrodes. Motion artifacts caused by usual desk works were investigated. This study shows the feasibility of the method for long-term, convenient, everyday use
this is a full textbook and canbe obtained from the publishers: Springer Verlag
Whether resting heart rate (RHR) predicts mortality independent of fitness is not well established, particularly among women. We analyzed data from 56,634 subjects (49% women) without known coronary artery disease or atrial fibrillation who underwent a clinically indicated exercise stress test. Baseline RHR was divided into 5 groups with <60 beats/min as reference. The Social Security Death Index was used to ascertain vital status. Cox hazard models were performed to determine the association of RHR with all-cause mortality, major adverse cardiovascular events, myocardial infarction, or revascularization after sequential adjustment for demographics, cardiovascular disease risk factors, medications, and fitness (metabolic equivalents). The mean age was 53 ± 12 years and mean RHR was 73 ± 12 beats/min. More than half of the participants were referred for chest pain; 81% completed an adequate stress test and mean metabolic equivalents achieved was 9.2 ± 3. There were 6,255 deaths over 11.0-year mean follow-up. There was an increased risk of all-cause mortality with increasing RHR (p trend <0.001). Compared with the lowest RHR group, participants with an RHR ≥90 beats/min had a significantly increased risk of mortality even after adjustment for fitness (hazard ratio 1.22, 95% confidence interval 1.10 to 1.35). This relationship remained significant for men, but not significant for women after adjustment for fitness (p interaction <0.001). No significant associations were seen for men or women with major adverse cardiovascular events, myocardial infarction, or revascularization after accounting for fitness. In conclusion, after adjustment for fitness, elevated RHR was an independent risk factor for all-cause mortality in men but not women, suggesting gender differences in the utility of RHR for risk stratification. Copyright © 2014 Elsevier Inc. All rights reserved.
Elevated heart rate (HR) during hospitalization and after discharge has been predictive of death in patients with acute myocardial infarction (AMI), but whether this association is primarily due to associated cardiac failure is unknown. The major purpose of this study was to characterize in 1,807 patients with AMI admitted into a multicenter study the relation of HR to in-hospital, after discharge and total mortality from day 2 to 1 year in patients with and without heart failure. HR was examined on admission at maximum level in the coronary care unit, and at hospital discharge. Both in-hospital and postdischarge mortality increased with increasing admission HR, and total mortality (day 2 to 1 year) was 15% for patients with an admission HR between 50 and 60 beats/min, 41% for HR greater than 90 beats/min and 48% for HR greater than or equal to 110 beats/min. Mortality from hospital discharge to 1 year was similarly related to maximal HR in the coronary care unit and to HR at discharge. In patients with severe heart failure (grade 3 or 4 pulmonary congestion on chest x-ray, or shock), cumulative mortality was high regardless of the level of admission HR (range 61 to 68%). However, in patients with pulmonary venous congestion of grade 2, cumulative mortality for patients with admission HR greater than or equal to 90 beats/min was over twice as high as that in patients with admission HR less than 90 beats/min (39 vs 18%, respectively); the same trend was evident in patients with absent to mild heart failure (mortality 18 vs 10%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
Concepts of fever from Hippocrates to the present are briefly outlined and compared with current ideas of the pathogenesis of fever. Evidence is presented that endogenous pyrogen, the hormone that elevates body temperature, is identical with lymphocyte-activating factor, a monokine that stimulates lymphocyte proliferation and function. It now appears that inflammation and fever are closely interrelated phenomena that are modulated by a single hormone and that have been selected by evolution to protect the host against infection.
Fever: basic mechanisms and management
  • Philip A Mackowiak
Philip A. Mackowiak, Fever: basic mechanisms and management. Lippincott Williams & Wilkins, 1997.
Agreement between measures of pulmonary artery and tympanic temperatures
  • K Lattawo
  • J Britt
K. Lattawo, J. Britt and M. Dobal, "Agreement between measures of pulmonary artery and tympanic temperatures", Research in Nursing & Health, 1995.