Keywords

1 Introduction

The constant development of technology has allowed a greater distribution of information, interconnection and unimaginable cultural and social progress [1, 2]. Notably in this century, science, technology, engineering, and mathematics are present in almost all aspects of people’s lives, since their academic training [3, 4]. The impact produced by this accelerated technological innovation has led to social and economic changes [5]. In particular, the incursion in the field of process automation and robotics has caused certain trades to be replaced by machines, producing a “technological unemployment” [6]. With this, work done generationally by human beings could be replaced by automatons that incorporate artificial intelligence algorithms [7]. This encourages government institutions in developing countries to train engineers and scientists of the future and improve society’s literacy in these fields. The application of new techniques to generate an education of excellence will improve the intellectual capital that interacts with smart cities, despite a marked social inequity and deep environmental problems. In this context, the STEMs are created, subjects for a prosperous economy and for a safe and healthy society [8, 9]. STEM education is an interdisciplinary approach to learning that removes the traditional barriers of these four disciplines and integrates them into the real world with rigorous and relevant experiences for students.

In developed countries, the vast majority of institutions focus on teaching “S” sciences and “M” math, paying very little attention to “T” technology that reflects the products and systems that most human beings need and less to the “E” engineering that reflects the design and innovation process of each system [8]. The integration of these 4 subjects is not achieved properly and the sciences and mathematics are still taught in an isolated and preponderant way to the remaining [10]. An appropriate definition is presented in [11], where it is described that STEM education contemplates the resolution of problems based on concepts and procedures of science and mathematics by incorporating work methodologies, in addition, engineering designs and the use of appropriate technology. In this way, STEM competences have become the center of global attention in the educational field, since having these skills is increasingly demanded in certain specific professions [12]. STEM education is considered of paramount importance in many nations, as it promotes innovation, productivity, and general economic growth. Addressing the range of possible directions that STEM education can take in primary-level educational institutions or suggesting new approaches is complicated and challenging, since the topics to be dealt with in the curriculum are broad [13].

Despite the promotion made by doctors, employers, politicians, and businessmen in the last decade, STEM education in the classroom is not adequate [14]. This has caused the students’ interest in pursuing technical careers to decrease, resulting in a lack of well-trained engineers, technicians, and researchers. Although it is recommended to increase the presence of engineering in the elementary and secondary grades, assigning equal time to the other disciplines does not seem feasible in many already saturated curricula. However, given the significant contributions of design and engineering processes to society, this discipline visibly supports its importance within the curriculum; avoiding dulling its potential to enrich other disciplines and foster an early interest in learning STEM [15, 16]. Unlike engineering as a lagged member, technology is experiencing greater interest with the gradual implementation of new tools and computerized systems. With the growing popularity of basic programming in software developed for school environments and the expansion of associated computational thinking skills, the educational landscape is changing rapidly [17].

Emphasis should be placed on providing adequate training to teachers, as they are responsible for guiding the student in STEM education [18]. Teachers’ professional development programs should provide learning opportunities for teachers themselves, to deepen their conceptual understanding and participation in scientific and/ or engineering practices. In addition, to appreciate science as a form of knowledge, in a community of knowledge builders and know how to interrelate it with other disciplines. Since, as is public knowledge, these are dictated separately or in blocks.

2 Related Works

It is often claimed that the dominant approaches to STEM education used in schools do not reflect the natural way in which disciplines are connected in the real world. School subjects tend to be taught in isolation, in a society where students must acquire knowledge and skills from multiple disciplines to provide solutions to political, economic, and social challenges. Although the views vary, the teaching should be inclusive as it is presented in [19], because it is a continuous and dynamic process, where the student represents the central axis. The real challenge for educators lies in how disciplines can be integrated effectively and at the same time guarantee the integrity of each one. The need to prepare students with 21st century skills through STEM-related teaching is growing, especially at the primary level, as described in [20]; this work theoretically justifies the implementation of workshops and robotics classes to increase mathematical literacy, scientific-technical information, and social skills. A survey is applied to teachers and future teachers, obtaining positive results that support this research; evidencing the need to introduce these activities at the primary level, to develop appropriate knowledge, skills and aptitudes for the current labor demand. Similarly, in the study of [21] issues related to STEM education are analyzed; this includes: previous experiences, research, publications and a review of examples of the implementation of robotics, programming and associated educational activities in primary school. There were 91 primary school teachers and future teachers from Poland and Ukraine, and a 15-question survey was conducted to validate the results, as part of the “Robotics and children” pedagogical research. The study was carried out to determine the needs of modern education, and to introduce the basic concepts of robotics in the elementary school educational process, hoping that in the coming years it can be carried out in secondary schools and VET (Vocational Education and Training).

Although the idea of using robotics elements in the learning process is no longer new and innovative, results can still be checked based on the implementation of new tools with higher performance. The application of activities and modules completely oriented to the teaching of robotics, guarantee a better cognitive development and increase motivation in the student, as shown in [22]. This study provides a research model and five tools (different questionnaires before and after research, applied to students and teachers) to evaluate the results of organized robotics activities outside the school day. This model was tested with students who run the risk of leaving school early and students participating in robotics activities to develop their computational thinking. One technique used for greater interaction between children and robotics is their participation in events such as the “FIRST® LEGO® League” championship and then spread their experiences [23]. This manuscript provides objective data obtained from the opinions of teachers and students who participated in this championship. A globalizing approach is applied to the different areas of the curriculum and the impact of STEM competencies in the secondary education learning process is analyzed. The execution of surveys allows us to conclude that both teachers and students agree that this type of event promotes interest and scientific curiosity, as well as social skills through teamwork.

As it has been shown both in theory and in practice, the implementation of teaching tools and modules that involve robotics, contribute positively to the student’s learning process. In this context, this study presents a prototype educational mobile robot built with materials and low-cost devices that contribute to the teaching-learning process of STEM skills. To make a greater interaction with the robot, the user is allowed to observe the operation of sensors and actuators, to understand how physical magnitudes vary in the real world. Experimental tests with the assembled mobile robot and the results obtained from the learning and usability tests performed on users allow this proposal to be approved.

This document is divided into five sections, including the introduction in Sect. 1 and the related works in Sect. 2. Section 3 presents the materials and methods used and Sect. 4 describes the results obtained. Finally, discussions and conclusions are presented in Sect. 5.

3 Materials and Methods

The purpose of the educational robot is to provide the teacher with technological tools to instruct users (school students between 11 and 13 years old) in STEM competitions. For this, a mobile robot with several sensors and actuators is proposed that allow the analysis of physical variables, incorporating connectivity means that use known technological resources, and that allow interaction with the mobile robot. In addition, it is important to use low-cost devices that allow replicating the proposal with few resources in similar projects, using easily accessible equipment and with flexibility of use.

Figure 1 shows the components of the proposed robot, where the Arduino card is used as a system information processor. The system inputs are distance, weight, temperature, humidity, and color sensors to analyze physical measurements and states in the classroom, data that can be displayed on the liquid crystal display (LCD). Robot mobility is generated by two direct current motors arranged in the form of a unicycle mobile robot to control linear and angular movements. In addition, it has a Bluetooth module that allows the robot to be connected to an external device (computer or smartphone).

Fig. 1.
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General diagram of the educational mobile robot.

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3.1 Hardware

The external structure of the mobile robot is carried out with an aesthetic and colorful criterion to capture the attention of students and of little weight to facilitate the manipulation of the prototype. In this way, all components are designed using computational assistance, as 3D solids. Figure 2 shows the robot made in AutoCAD; in the front part, the spaces to locate the distance sensor and the LCD are observed, in the upper part an area for the color sensor is established and a plate for the operation of the balance is mounted, in the rear part are the circuit and the temperature sensor, and at the bottom are the driving wheels and the crazy wheel. All these components are generated by 3D printing with polylactic acid (PLA).

Fig. 2.
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3D design of mobile robot.

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Another physical subsystem of the mobile robot is the electronic circuit; this is developed using low-cost components. In Fig. 3 it can be seen the proposed circuit designed in the Fritzing software, where Arduino UNO is presented as the main control device, connected to several complementary elements. These are described below: a 9 V battery that provides the power for the operation of the sensors, actuators, controllers and LCD; two DC motors that operate with a TB6612NG driver that allows you to control the speed and direction of rotation; an LCD that has an I2C adapter that reduces connections to two communication cables. In addition, a 5Kgr load cell is placed that has an HX711 adapter and allows I2C communication; Color (TCS3200), distance (HC-SR04) and temperature (DHT) sensors use digital pins for reading data. The Bluetooth module connects to the serial communication pins of the Arduino.

Fig. 3.
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Connection diagram of the proposed electronic circuit.

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3.2 Software

As part of the software design a main program installed in the Arduino is developed, and two user interface applications for computer and mobile device respectively. Figure 4 shows the flow chart with which the main control program operates. In the first instance, all the input and output devices connected to the Arduino are configured and the operating mode is selected, which can be chosen from the phone or the computer. When choosing the sensor mode, the data of any of the sensors (distance, temperature, humidity, weight and color) can be displayed, this information is displayed on the LCD and sent via Bluetooth. In the case of choosing the movement mode, the prototype can be controlled by phone or computer. This cycle is repeated simultaneously the times that the user requires or otherwise the programming comes to an end.

Fig. 4.
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Flowchart of the main control program.

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The user interface of the phone is developed in App Inventor and is compatible with devices that have an Android operating system. Figure 5 shows the screens designed for the mobile application. The main window has the connection buttons of the device via Bluetooth (blue), of the sensors for reading data (red), and of the robot control (green). The sensor screens have illustrative images that present the data of the measured variables and the motion control interface allows to command the linear and angular displacements of the mobile robot.

Fig. 5.
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Screens that make up the mobile user interface.

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The computer user interface is implemented in the MATLAB software, using the coding tools (uicontrol), the two windows for interaction with the robot are shown in Fig. 6. The start window allows wireless communication to start with the Bluetooth device selected. Next, the main window presents the data of all the sensors in the robot, including a box that shows the color measured by the TCS320 module, also has the buttons to control the movements of the mobile robot.

Fig. 6.
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Screens that make up the user interface for PC.

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4 Experimental Results

The respective performance tests of the implemented system are performed, reviewing the correct functioning of all its elements. As can be seen in Fig. 7, the robot is in full operation, where all the components of the system work within the ranges established in its design and the external applications present a satisfactory communication.

Fig. 7.
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Tests carried out with the educational mobile robot.

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4.1 Participants

Two schools in Ambato (Ecuador), all non-private (state and free) participated in this study; where 45 students of eighth level of basic training, 24 boys and 21 girls, with an average age of 12 years (K-12) were selected. Considering that the participants’ mother tongue is Spanish, all activities (orally and in writing) were based on that language. Engineering design processes require long-term development, so it is necessary to start in the first years of secondary education. State schools were chosen, with the commitment to present engineering education to low-income people, in order to increase their interest in STEM education. Figure 8 shows some of the students who evaluated the educational robot.

Fig. 8.
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Participants interacting with the educational robot.

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All schools expressed their enthusiasm and openness for their students to participate in new learning experiences. These experiences were new for some teachers and their students, by interacting directly with the mobile robot. 17 teachers participated (10 men and 7 women) with extensive experience in school education. Both teachers and students participated in eventual informational meetings, before and after the execution of each experiment. Your comments were taken into account, as part of the respective feedback process. It should also be noted that the authors of this document provided their experiences within the field of engineering in order to be a real example of pursuing engineering careers.

4.2 Learning Test

The purpose of this proposal is to instruct school students in STEM competitions, so a learning test is designed based on the skills, knowledge and work activities provided by the educational mobile robot [8]. Table 1 presents the questions posed in the learning test, each affirmative answer question is equivalent to one point in the total score.

Table 1. Learning test questions.
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Regarding the questions formulated in the learning test, a simple writing has been carried out, avoiding technicalities and that allows to determine in a statistical way the knowledge acquired by the student during the development of this experiment. Next, a contextual justification of the content of each question is briefly described, so in questions 1 and 3 a real application of the use of temperature and humidity sensors is presented; and weight, color and distance sensors respectively. Question 2 demonstrates its interaction with technological tools that improve conventional learning and 4 allows you to evaluate your knowledge about units of measure and perform conversions. In the fifth question you can evaluate its conception about the sensors and actuators that make up the robot, and in the sixth question identify the general characteristics of the robot. Questions 7 and 8 have a certain technical criterion, which allows to determine their interaction with computer systems when talking about the use of sensors to obtain data and the use of mobile and computer applications respectively.

The learning test is applied before and after the training process with the mobile robot in the 45 students selected and Fig. 9 shows the results of the learning test. In the pretest, low scores are observed, except in question 3, where 31 students indicated knowing about units of measurement, in the other questions not even half of the total score is reached. In the posttest all students answered affirmatively to questions 1, 4 and 8, and in the rest of the questions there was also a considerable improvement in the scores regarding the pretest.

Fig. 9.
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Learning test results.

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4.3 Usability Test

At the end of the activities, the level of satisfaction that teachers perceive with the interfaces presented during the experiments developed is evaluated. It should be emphasized that this test requires the participation of people with trained criteria and that it is the teachers who will benefit from this technological tool to improve learning. For this stage, a questionnaire based on the SEQ usability test developed by Gil-Gómez et al. [24] with a certain variant oriented to this proposal. There are 13 questions that are assessed with a score of 1 to 5 points according to the following scheme: the first seven questions (Q1 - Q7) are related to the level of acceptance. The following four questions (Q8 - Q11) are related to the effects and discomforts that the system can cause, such as: nausea, disorientation or eye discomfort, as well as its contribution to the teaching process. The next two questions are related to the difficulty of performing the tests. If the result obtained is in the range of 40-65, the implemented system is considered acceptable. The questions asked to the teachers about the proposal when applying the SEQ questionnaire are shown in Table 2. As can be see there is a positive result that allows validating the system proposed for the students and the comments were collected to improve the system later.

Table 2. Results of the questionnaire implemented based on the SEQ test.
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5 Discussions and Conclusions

Although in the traditional education model the subjects are taught separately, a new challenge of STEM competencies is to integrate them to ensure the transmission of knowledge in a more efficient way, responding to current professional requirements. Thus, school-age children who receive this special training can acquire greater skills and aptitudes, necessary to improve their learning process. In the presented literature it can be seen that in several parts of the world it is intended to implement engineering education in schools, characteristically of robotics. In particular, in this proposal a prototype educational robot has been designed and built that gathers other complementary knowledge from mathematics and engineering, in order to provide better results. Innovation and interest that an automaton arouses in a child is encouraged, to allow him to learn while having fun and experiencing an unconventional activity within the classroom.

In this way, teachers are provided with a technological tool that facilitates their work by promoting the full learning of STEM skills, i.e. the use of technology and automation in young students. The mobile robot implemented in this work shows the student how physical quantities are present in their environment and how they can be converted into digital variables. All this thanks to the use of sensors and actuators found in automatic, domotic and industrial systems, learning in a fun way and creating a context that allows you to have a professional inclination in the future towards a certain branch of science.

This work is carried out using low-cost devices that allow the proposal to be replicated with a reduced economic investment. In addition, the robot has wireless connectivity via Bluetooth that allows remote operation and easier interaction between student and teacher. The proposal is evaluated in the classroom with 45 students with an average age of 12 years, with the supervision of experienced teachers. The results indicate an increase in students’ knowledge in the learning test questions, instructing users in STEM competitions. A usability test is also applied to teachers in charge, obtaining an acceptable usability score (59.1 ± 0.20), which demonstrates the satisfaction obtained with the system presented.