Vital Signs Monitoring Based on Pulse Oximeter Sensor and IoT platform Radovan Korček * , Darina Jarinová * * University of Žilina, Faculty of Electrical Engineering and Information Technology, Žilina, Slovakia radovan.korcek@feit.uniza.sk, darina.jarinova@uniza.sk Abstract— Modern healthcare uses wireless technology for automatic remote monitoring of the patients. The IoT plays a significant role in a broad range of healthcare applications, such as managing chronic diseases or disease prevention. This paper presents the design and implementation of the IoT platform to monitor vital signs, mainly oxygenation of the blood, body temperature and pulse rate. The aim of the project was to support students to improve their technical skills during distance learning. The main goal of this project was to design a platform that allowed a patient with Covid disease to measure blood oxygenation at home. The outcome of the project is a wearable IoT solution, of which the HW part is based on the Arduino UNO controller, Bluetooth communication module and a low-power pulse oximeter sensor. Besides measuring oxygenation of the blood, it can monitor other vital signs such as heart pulse and body temperature. I. INTRODUCTION It is the Internet of Things (IoT) that play a significant role in a broad range of e-health applications, such as managing chronic diseases or disease prevention. IoT-based and other remotely working healthcare solutions are on the rise and at the 2020 made up roughly 9% in global shares of enterprise IoT projects [1]. IoT based devices employ various sensors in order to collect patients’ physiological information and deploy gateways and a cloud, which provide data storage and analysis functions. Such IoT based wearable devices provide a continuous automated flow of information and can replace the need for regular healthcare professional check-ups. Applications include remote patient monitoring, which is used to securely capture patient health data from a variety of sensors, applying algorithms to analyse the data and then share them with medical professionals who can make appropriate health recommendations [2]. Wearable devices also provide more inside into health condition during the different types of activity. One of the most popular devices targeting this purpose are fitness bracelets, smart watches or intelligent clothing [3]. The global Covid pandemic has caused different alternative methods of education to be created and employed. Project-oriented teaching is becoming very effective, whether within distance or face-to-face education. Many IoT solutions are feasible as small home projects for students, thus they are very appropriate during distance learning in engineering and informatics. Simple IoT project can acquaint a student with the basic principles of data acquisition, transfer, analysis and storage. The main goal of the presented student project was to design a low-cost platform that allowed a person with a suspected Covid disease or a Covid patient to easily measure blood oxygenation at home. Although most cases of COVID-19 are mild, the health condition of some patients can deteriorate rapidly, usually during the second week of illness. There are also reports of infected patients who develop silent hypoxemia, when blood oxygen saturation levels are exceedingly low despite patients not exhibiting shortness of breath or other symptoms of respiratory distress, leading to dangerous delays in care [9]. Outcome of the presented student project is a wearable IoT solution, of which the HW part is based on the Arduino UNO controller, Bluetooth communication modul and a low-power modul consisted of pulse oximeter and pulse rate sensors. Besides measuring oxygenation of blood, it can monitor other vital signs such as heart pulse and can be easily extended to measure body temperature. In this paper, we provide some details on system design and implementation from the student’s perspective. We also share student’s experience with the system implementation, and how was dealt with various unexpected issues during the system design and its practical solution. Such information might be valuable for other students and their supervisors engaged in project-based learning. II. TECHNICAL BACKGROUND A. Vital signs sensing There are three main vital physiological signs, which are required for the diagnosis and during the course of treatment, namely body temperature, heart pulse rate and breathing cycle. For our purposes, we chose the heart rate as the vital sign being monitored. Various methods are used to measure heart rate including Electrocardiography (ECG), Photoplethysmography (PPG), Oscillometry (meaning monitoring of blood pressure) and Phonocardiography (PCG) [3]. We selected PPG as the method to measure the heart rate, mainly due to its low cost and portability. The PPG sensor capable of measuring pulse can be also used to measure different physiological signals, e.g. oxygen levels. PPG is often obtained by using Pulse oximetry [13]. B. Pulse oximetry Pulse oximetry market is experiencing rapid growth mainly due to the increasing elderly population, which is prone to the risk of different types of diseases that could affect oxygen levels. This in return put emphasis on patient safety during treatment in healthcare settings and increases demand for consistent vital signs monitoring. The global pulse oximeter market is expected to rise at an absolute