Memoria Investigaciones en Ingeniería, núm. 26 (2024). pp. 244-264
https://doi.org/10.36561/ING.26.15
ISSN 2301-1092 • ISSN (en línea) 2301-1106 – Universidad de Montevideo, Uruguay
Este es un artículo de acceso abierto distribuido bajo los términos de una licencia de uso y distribución CC BY 4.0. Para ver una
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Memoria Investigaciones en Ingeniería, núm. 26 (2024). pp. 244-264
https://doi.org/10.36561/ING.26.15
ISSN 2301-1092 • ISSN (en línea) 2301-1106 – Universidad de Montevideo, Uruguay
Este es un artículo de acceso abierto distribuido bajo los términos de una licencia de uso y distribución CC BY 4.0.
Para ver una copia de esta licencia visite https://creativecommons.org/licenses/by/4.0/
Design of a low-cost portable electrocardiograph for telemedicine application
Diseño de un electrocardiógrafo portátil de bajo coste para su aplicación en
telemedicina
Conceção de um eletrocardiógrafo portátil de baixo custo para aplicação em
telemedicina
Hólger Santillán
1
(*), Angelo Mantilla
2
, David Cárdenas
3
, Peregrina Wong
4
Recibido: 24/03/2024 Aceptado: 31/05/2024
Summary. - This paper presents the design of a portable electrocardiograph designed to provide community health
care. The AD8232 main sensor has multiple options for displaying cardiac activity. The first option uses the serial
plotter in the Arduino IDE, while the second employs LabVIEW, allowing additional observation of the patient's blood
pressure via block coding. In addition, the Arduino cloud is integrated to process the information captured by the
ESP32, enabling visualization on any device with internet access. Through this platform, it is possible to download
the studies performed in different periods (1 hour, 1 day, 7 days, and 15 days), with an efficiency percentage of 4.11%.
Keywords: Portable Electrocardiograph; Healthcare; IoT; Community; Cardiac Activity.
Resumen. - El presente trabajo presenta el diseño de un electrocardiógrafo portátil diseñado para proporcionar
asistencia médica comunitaria. Se emplea el sensor principal AD8232, con múltiples opciones de visualización de la
actividad cardíaca. La primera opción utiliza el serial plotter en el IDE de Arduino, mientras que la segunda emplea
LabVIEW, permitiendo la observación adicional de la presión arterial del paciente mediante codificación de bloques.
Además, se integra la nube de Arduino para procesar la información capturada por el ESP32, lo que posibilita la
visualización en cualquier dispositivo con acceso a internet. A través de esta plataforma, se pueden descargar los
estudios realizados en distintos lapsos de tiempo (1 hora, 1 día, 7 días y 15 días), con un porcentaje de eficacia del
4.11%.
Palabras clave: Electrocardiógrafo portátil; Asistencia Sanitaria; IoT; Comunidad; Actividad Cardiaca.
Resumo. - Este artigo apresenta o projeto de um eletrocardiógrafo portátil projetado para prestar cuidados de saúde
comunitários. O sensor principal AD8232 possui múltiplas opções para exibir a atividade cardíaca. A primeira opção
(*) Corresponding Author
1
Master en Telecomunicaciones. Universidad Politécnica Salesiana, Grupo de Investigación en Sistemas de Telecomunicaciones – GISTEL,
Universidad de las Palmas de Gran Canaria, hsantillan@ups.edu.ec holger.santillan101@alu.ulpgc.es,
ORCID iD: https://orcid.org/0000-0003-4803-7016
2
Ingeniero en Telecomunicaciones. Universidad Politécnica Salesiana, Grupo de Investigación en Sistemas de Telecomunicaciones - GISTEL,
amantillam1@est.ups.edu.ec , ORCID iD: https://orcid.org/0009-0000-2163-8714
3
Master Universitario en Tecnologías y s\Sistemas de Comunicación. Universidad Politécnica Salesiana, Grupo de Investigación en Sistemas de
Telecomunicaciones - GISTEL, dcardenasv@ups.edu.ec , ORCID iD: https://orcid.org/0000-0003-4241-9929
4
Ingeniera electrónica. Universidad Politécnica Salesiana, Grupo de Investigación en Sistemas de Telecomunicaciones – GISTEL, Universidad
de las Palmas de Gran Canaria, peregrina.wong101@alu.ulpgc.es ORCID iD: https://orcid.org/0000-0003-1290-7729
H. Santillán, A. Mantilla, D. Cárdenas, P. Wong
Memoria Investigaciones en Ingeniería, núm. 26 (2024). pp. 244-264
https://doi.org/10.36561/ING.26.15
ISSN 2301-1092 • ISSN (en línea) 2301-1106 – Universidad de Montevideo, Uruguay 245
utiliza o plotter serial no Arduino IDE, enquanto a segunda utiliza o LabVIEW, permitindo observação adicional da
pressão arterial do paciente por meio de codificação em bloco. Além disso, a nuvem Arduino está integrada para
processar as informações captadas pelo ESP32, possibilitando a visualização em qualquer dispositivo com acesso à
internet. Através desta plataforma é possível baixar os estudos realizados em diferentes períodos (1 hora, 1 dia, 7
dias e 15 dias), com percentual de eficiência de 4,11%.
Palavras-chave: Eletrocardiógrafo Portátil; Assistência médica; IoT; Comunidade; Atividade Cardíaca.
1. Introduction. - The electrocardiogram is known as a non-invasive medical test that records the electrical activity
of the patient's heart. It is used to evaluate the health of the most important organ, the heart, and to detect possible
cardiovascular problems. During an electrocardiogram, electrodes are attached to the skin at different locations on the
human body, such as the chest and upper and lower extremities [1], [2].
During the pandemic or situations in which it has been difficult for patients to approach a medical center to review
the information or know the status of the study has been a limiting factor either physical, personal, or environmental
conditions and this has severely affected humanity during this health crisis [3], [4].
At present, there is a solution to this problem, which consists of the use of medical equipment capable of connecting
to the network and sending the information obtained in real time, which will be stored in a cloud and can be viewed
by anyone who requires it [5], [6].
The use of the IoT (Internet of Things) connection in medical equipment has the purpose of improving the quality of
service both to better process the studies and to provide the doctor with the facility to visualize the information to
perform an analysis anywhere on the planet. This has represented a great improvement in the field of health, allowing
Telecommunications and Medicine to work together [7], [8].
IoT communication is based on a device that acts as a transmitting antenna, in our case the ESP32, which receives the
processed signal through its ports and proceeds to send it to the Arduino cloud. This device is one of the main options
to consider when making an IoT connection due to its advantages over other components that do not have this
capability [9], [10].
In the design of this article, Arduino Uno is used as the receiver and will be the one to process the information from
the AD8232 sensor which captures the cardiac signal in analog form. The Arduino transforms the analog signal to
digital for easy reading and sends the data to the other stages of the design, sending the COM port to the LabVIEW
software which through the LINX library helps to make the connection of the system [11], [12].
At this stage the LabVIEW software provides a plus to the design since the blood pressure is displayed along with the
graph of the cardiac activity of the heart, normally in other mostly analog equipment this result is displayed every
minute, but through the formula for the prediction of blood pressure (equation 1), the prediction is obtained every 15
seconds which provides a much faster response to conventional [13], [14].
The final and most important step of this design is to send the information to the Arduino ESP32 Wi-Fi module which
is previously linked to the Arduino cloud where, through its interface, the cardiac activity can be observed in real-time
and this collection of information can be downloaded through an Excel file in comma delimited format for processing
[15], [16].
The tracing shown in Figure I is the result of a simulation performed using BTL Cardiopoint software. This software
is used as an electrocardiogram (ECG) simulator, allowing various clinical conditions and scenarios to be accurately
recreated. The graphical representation provides detailed information about the electrical activity of the heart and is
useful for medical education and cardiovascular research. This tracing, generated using the aforementioned software,
provides a valuable tool for the analysis and interpretation of cardiac activity in controlled settings. In addition, it
facilitates the practice of ECG interpretation, helping to improve the diagnostic and patient management skills of
healthcare professionals [17], [18].
H. Santillán, A. Mantilla, D. Cárdenas, P. Wong
Memoria Investigaciones en Ingeniería, núm. 26 (2024). pp. 244-264
https://doi.org/10.36561/ING.26.15
ISSN 2301-1092 • ISSN (en línea) 2301-1106 – Universidad de Montevideo, Uruguay 247
1.1 Related Work. - The authors of the article [16] mention that currently, many people die of cardiac arrest, due to
a poor check and control of the state of their cardiovascular system. They propose a solution to this problem through
their design, which is based on the realization of a cardiac activity monitor using the AD8232 sensor and an ESP32
that serves as a microprocessor and the device responsible for the connection to the cloud using Ubidots and
Thingspeak [19], [20].
The authors of the article [5] designed an ECG that focuses on making the cost as low as possible, and at the same
time they implemented a system to detect any anomaly in the outlets, in the case of any, they will send an alert message
to the doctor or the person in charge. The design has a Bluetooth connection system that covers a distance of 100
meters. It is concluded that its design is a great advance for society and a great alternative for people or entities that
need to start in the cardiovascular care of their patients because the manufacturing cost of the proposed design is
significantly lower than other models previously considered [21], [22].
The authors of the article [3] state that cardiovascular care awareness has now increased due to the emergence of
COVID-19, since during the pandemic period, the number of deaths due to cardiac arrest increased considerably. They
point out that the speed of detection time is crucial to avoid irreparable damage to human life.
They concluded that the design will be very useful because it can accommodate the information collected through
unique record codes that will facilitate the search of the records [23], [24].
The authors mention that about 30% of the population in rural areas of Bangladesh lives in poverty. Due to the lack
of modern medical technology in these areas, medical care and diagnostic services are limited for rural residents. As
a result, adequate medical care is inaccessible to the rural population. In this context, modern technology could be
implemented to address their health problems. For example, electrocardiogram (ECG) sensing tools connected to the
human body can be used to collect essential cardiovascular data through Internet of Things (IoT) devices [22].
The authors of the article mention that, in recent times, several researchers have explored the connection between
emotions and people's physical well-being. This research interest has intensified due to the rapid progress of computer
technology, especially in the biomedical field. In the field of engineering, there is a focus on understanding how
emotions affect the human body, which motivates researchers to conduct studies in this area. It should be noted that
this design does not have an information storage system, nor does it have the function of sending the information to
the cloud, it only focuses on the analysis and visualization during the ECG [1].
The aforementioned authors presented their devices to the world, some of them stand out in some particular quality
depending on the case. But they all fulfill their general purpose, to provide a tool for the care and prevention of
cardiovascular problems in humans, these articles were of great help in guiding which direction could focus the
analysis of this study and what other issues to innovate as evidenced in the implementation of the pressure gauge in
LabVIEW, therefore this article has great advantages to take into consideration as shown in the results section.
1.2 Arterial prediction formula implemented in LabVIEW. - The equation for blood pressure prediction (1) used
in LabVIEW is as follows:
Where:
Equation 1 is used to calculate blood pressure using radial pulse-taking techniques, whereby, if the pulse during the
first 15 seconds is continuous, the value obtained is multiplied by 4, resulting in an accurate prediction of the value
that would be obtained if the pulse were taken for a full minute. One of the great advantages of using this method is
that physicians can know in advance the blood pressure coming from the individual under study.
H. Santillán, A. Mantilla, D. Cárdenas, P. Wong
Memoria Investigaciones en Ingeniería, núm. 26 (2024). pp. 244-264
https://doi.org/10.36561/ING.26.15
ISSN 2301-1092 • ISSN (en línea) 2301-1106 – Universidad de Montevideo, Uruguay 248
2. Method. - For the design of the electrocardiograph, first of all, the placement of the electrodes and the type of data
obtained through the AD8232 sensor are identified and coded using Arduino. The information obtained is analyzed
locally using the Serial plotter in the Arduino IDE. Then, using LabVIEW, a graphical interface is created to visualize
the electrical activity of the heart and make a blood pressure prediction, which is obtained every 15 seconds as opposed
to the manual method, which is obtained every minute. Finally, the Arduino cloud is used to open the doors to the
world of IoT, it is observed by any device with internet access and as an additional benefit, the report of the data
received is downloaded as a text file [25], [26].
The advantage of using the AD8232 sensor is its ease concerning its size, which allows it to make cases, thus
facilitating its portability with the patient. This sensor handles 3.3 volts, obtained through the Arduino, which is
powered with 5V. This also facilitates the use of portable batteries with which the portability of the prototype is
enhanced [27], [28].
It is important to mention the advantage of downloading the information containing the studies performed on each
patient in a comma delimited file that can be opened by Excel and obtain the details every second of the reading of
the data of the electrical activity of the heart, this information needs to be processed as shown below. With the
information already processed, a more in-depth analysis is performed in the cardiovascular area.
Below, in Figure II, a scheme is presented to explain more simply the stages of processing and analysis of the
prototype.
Figure II. Outline of the proposed design.
Where:
1. Placement of the electrodes on the patient.
2. Recording of electrical measurements of the heart using the AD8232 module.
3. Processing of the measurements taken by the Arduino.
4. Visualization of the cardiac activity on the monitor through Arduino and LabVIEW.
5. Sending the data of the measurements to the cloud.
6. Remote viewing of the analysis performed.
The most important materials used in the development of this design are the following:
-Arduino UNO.
-AD8232 sensor.
-ESP32.
-Cables to interconnect the devices with each other.
H. Santillán, A. Mantilla, D. Cárdenas, P. Wong
Memoria Investigaciones en Ingeniería, núm. 26 (2024). pp. 244-264
https://doi.org/10.36561/ING.26.15
ISSN 2301-1092 • ISSN (en línea) 2301-1106 – Universidad de Montevideo, Uruguay 249
Figure III shows the physically assembled prototype circuit, which represents the design of a portable
electrocardiograph intended to provide medical assistance to the community. The circuit incorporates the use of the
AD8232 as the primary sensor for accurate detection of cardiac activity. In addition, it offers three options for
displaying the heart rate graph, allowing for versatile monitoring that is adaptable to the user's needs. This innovative
design seeks to provide an affordable and effective solution for cardiac monitoring in medical and community settings,
thus contributing to improving cardiovascular health and quality of life.
Figure III. Physically assembled circuit.
Figure IV shows the torso of a patient with the electrode arrangement of the prototype circuit of a portable
electrocardiograph. These electrodes, essential for accurate detection of the heart rhythm, are strategically placed
following standard medical guidelines as follows.
- Red electrode: located on the right side of the right torso on the lateral side (1).
- Yellow electrode: located on the left side of the torso at the level of the heart (2).
- Green electrode (Neutral): located under the last rib on the right side of the torso (3).
This innovative approach to electrocardiograph design reflects a significant advance in medical technologies, as it
enables effective, noninvasive cardiac rhythm monitoring in clinical and community settings. The correct arrangement
of the electrodes on the patient's torso ensures accurate and reliable measurements, which is critical for informed
medical decision-making and cardiovascular health care.
Figure IV. Placement of electrodes on the patient.
H. Santillán, A. Mantilla, D. Cárdenas, P. Wong
Memoria Investigaciones en Ingeniería, núm. 26 (2024). pp. 244-264
https://doi.org/10.36561/ING.26.15
ISSN 2301-1092 • ISSN (en línea) 2301-1106 – Universidad de Montevideo, Uruguay 250
2.1 LabVIEW Block Diagram Configuration. - Next, each of the steps related to the configuration of the block
diagram used in LabVIEW, as shown in Figure V, are detailed. In this comprehensive analysis, each of the components
and connections of the diagram are addressed, explaining their function and their contribution to the overall system
operation. In addition, the design decisions made during the creation of the block diagram are described, highlighting
their relevance to the success of the project.
This detailed approach provides a thorough understanding of the configuration process in LabVIEW, allowing readers
to become familiar with the techniques used and their application in the specific context of the project. This detailed
explanation seeks to provide clarity and facilitate replication of the process by other researchers or practitioners
interested in using LabVIEW for similar projects.
Figure IV. Configure Design in LabVIEW.
2.2 Configuration LabVIEW with Arduino. - In Figure VI, we initially present the COM port block, which is in
charge of reading the information through the COM ports of our PC. This information is sent to the Linx Open. vi file,
where the baud rate is set to 9600 to ensure optimal data transmission speed to the system.
Figure VI. Arduino communication block.
After establishing communication with the Arduino, an analog reading is made, because the information processed by
the sensor is of this type. It is established that the pin of the Arduino to which the reading is being made will be the
A0, after this process the acquired data is sent to be displayed on a display, which will also trigger an LED that will
show the heartbeat obtained.