Abstract:

The traditional education model is the most commonly employed at the School of Engineering of the National Autonomous University of Mexico (UNAM). The students who are abstract learners, a minority, benefit the most from this model of teaching the sciences.
Experimental laboratories provide students with the opportunity to directly engage with physical objects, allowing them to connect abstract knowledge with experiences acquired through the interpretation of measurements and observations. By using experiments as a bridge between the realms of the abstract and the concrete, students reinforce their learning and deepen their understanding of the subject matter.
The main objectives of experimental laboratories include improving mastery of the subject under study, developing practical skills such as teamwork, and cultivating an interest in learning science.
During the first half of the COVID-19 pandemic, classes were conducted online at UNAM’s School of Engineering. Simulators were employed to address the experimental components of physics and chemistry. However, they were not sufficient to cover the content fully.
Some professors of engineering science subjects, such as Circuit Analysis and Basic Electronics, proposed that their students carry out experiments at home, given the online availability of the needed devices and materials. Hence, it was verified that many students were able to perform experimental practices that required the assembly of electrical and electronic circuits.
Nevertheless, there were cases where it was not possible to conduct practices that required signal visualization. These shortcomings helped both students and professors to identify the tuition model's areas for improvement and the cases in which it is necessary to have experimental tools at home. The oscilloscope was perceived as one of them.
In 2021, the project "Design of Mechatronic Devices for Emergency Support" was initiated. One of its objectives was the creation of didactic materials and technological devices that would allow students to conduct experimental practices remotely or virtually. Within this project, the design of an accessible oscilloscope for engineering students was proposed.
A design methodology was implemented. Some of the design requirements considered were: ease of acquisition and low cost of components; ease of assembly, even for students without any background in electronics; and independence from any specific software platform.
A functional oscilloscope was successfully designed, consisting of an ESP32 board, a simple resistive circuit, a personal computer as a display element, and a specifically developed open-source visualization program. As with all other elements of the oscilloscope, the visualization program was developed with a didactic focus in mind.
The vast majority of UNAM students have access to a personal computer. Hence, the actual cost of the oscilloscope excluding the price of computer was less than 250 MXN, that is, 15 USD.
This oscilloscope is an easily replicable, adoptable, and modifiable device capable of obtaining useful measurements. Consequently, it facilitates the understanding of concepts related to electricity and electronics. It also functions as a real oscilloscope that students can continue to use both in their academic and professional lives.

Keywords:

Accessible oscilloscope, experimental learning, experimental laboratory, engineering learning, design methodology.