Phonocardiography and Photoplethysmography With Simple Arduino Setups to Support Interdisciplinary STEM Education

Abstract

Small computer board platforms, such as Arduino, Raspberry Pi, and micro: bit are very common, cheap, and useful tools to teach modern technology, coding, and experimenting in different disciplines at various levels. Due to the huge available information on websites, it is very easy to find a solution for almost any job and problem, therefore one may not be motivated to work out an own version, to study carefully, to understand the principles in-depth and to be creative. This is also one of the reasons why so high proportion of the examples employ technically inadequate methods, misleading concepts. These are rather serious problems concerning high-quality science, technology, engineering and mathematics (STEM) education. Although technology and available tools change rapidly, the basic principles remain the same, therefore education should focus on a better understanding of these. On the other hand, it is very important for the future's engineers, developers, and professionals to follow the correct methods, to be reliable, creative, and open to the more and more common interdisciplinary methodology. In this paper, we demonstrate this approach by investigating exciting interdisciplinary phonocardiography and photoplethysmography experiments and related electronics, data acquisition, and signal processing. In our work, we focus on the understanding and applying the correct methods, provide a detailed analysis of common pitfalls and leave room also for additional work. Students and teachers, lecturers can learn what to consider, pick what they find useful for their projects. It is also important to note, that the principles are valid for much other instrumentation and information processing jobs as well.

Universal Arduino-based experimenting system to support teaching of natural sciences

“…We try to balance an engineering-like and common approach in order to help students and teachers to freely but wisely use parts and tools previously employed only by engineers. We aim to show the most important standard rules and principles in the simplest and most understandable form [10][11][12][13][14]. The basics of practical electronics, instrumentation, coding and processing are typically covered.…”

“…Therefore, thermocouples, pick-up coils and Wheatstone bridges can also be connected without any additional circuitry. An infrared photodetector is also integrated and can be used as a photogate or as a sensitive photoplethysmograph to monitor the blood pressure changes in the finger [14]. The documentation is available openly [16] and it can serve as a tutorial on signal condition principles and solutions.…”

“…The code is openly available and due to the permissive license it can be modified to make it compatible with different host applications [16]. It can also be used as a reference, mainly because many questionable solutions have spread for implementing precisely timed sampling [14].…”

“…Figure 5 and figure 6 show two screenshots to illustrate these features. On the left hand side, a photoplethysmograph signal is displayed which is approximately proportional to the blood pressure changes in the finger [14]. The thresholds are used as event detectors and the time difference between successive heart beats can be displayed in real time.…”

“…The infrared photodetector part of the EDAQuino board can also be assembled in a breadboard [14]. This sensitive sensor can be used to follow motion of objects as well.…”