Sustainability means using resources in a way that does not harm the planet and it has become a key element in every industry. The UN Commission on Environment and Development provided the report “Our Common Future” in 1983 [1]. The report included a definition of sustainable development as development that “meets the needs of the present without compromising the ability of future generations to meet their own needs”.

Sustainability is considered to have three dimensions: environmental, social, and economic [2]. The environmental dimension of sustainability is usually emphasized. It focuses on global problems, including pollution, species extinction and biodiversity loss, climate change, deforestation, and loss of ecosystem services. Human activity is harming the planet, jeopardizing the future of humanity on it. Sustainability means using resources in a way that does not harm the planet, so that humankind may live well on it for a long time. The concept of sustainability indicates the wise use of natural resources catering to the needs of the planet’s population, helping economies grow, and meeting human development goals. It also indicates the protection and conservation of natural resources, enabling nature to provide the resources and ecosystem services that sustain life, making them available for all the generations to come. Sustainability, as a key element to every industry, can guide decisions and actions for development at the global, national, and individual levels aiming to meet goals for development. That is considered sustainable development. According to UNESCO, “Sustainability is often thought of as a long-term goal, while sustainable development refers to the many processes and pathways to achieve it” [3]. The UN adopted 17 Sustainable Development Goals (SDGs) in 2015. These are objectives that form a plan of sustainable development on a global level [4,5].

Sustainable design or “Design for Sustainability” means to base a design on any system and method that can fulfill the sustainability goals. The term “sustainable design” has been used in many disciplines, as well as in product design. Sustainable design integrates an environmentally friendly approach that considers nature’s resources to be a part of the design. Principles such as reducing waste, recycling plastics, upcycling materials, energy-saving, etc., allow for human activities to have less of an impact on the environment and help us address the challenge of designing products based on sustainable design. In such a way products are recyclable, compostable, or reusable [6]. Sustainable design creates solutions through reasonable consumption of the planet’s resources so that societies can live well and in harmony with the environment today and can safeguard their future. The concept of ‘Design for Sustainability’ (D4S) indicates that environmental, social, and economic concerns should be considered throughout the design process and the resulting product [6]. The conscientious effort to embed sustainability into curricula is defined as Education for Sustainable Development (ESD). ESD is defined by UNESCO (2021) as: “the process of equipping students with the knowledge and understanding, skills and attributes needed to work and live in a way that safeguards environmental, social and economic wellbeing, in the present and for future generations” [3,7]. The numerous definitions of ESD, outline the relationship between the environment, society, economy, and education to support the development of knowledge, skills, attributes, and values [8]. There is evidence of a growing trend in higher education institutions globally to embed ESD in curricula, providing mindful, transformative education that gives students a strong sense of agency and hope for a better future [9].

Worldwide, there is a rising number of efforts in academia to embed sustainability into curricula, so that students are provided with the necessary knowledge, skills, and attributes to act in their professional and private lives, in a way that protects the environment and enables well-being [9]. Within the work presented, researchers have investigated cases of embedding sustainability principles into higher education at the teaching and learning level. There are many cases of sustainability embedded into curricula and these include various subjects that are taught, i.e., basic science [10], business curricula [11], or engineering [12]. However, there are very few cases of sustainability embedded into mobile robotics courses at the higher education level. STEM and Educational Robotics are very popular in K-12 education, but there are limited works published regarding the sustainability and development of educational mobile robots in higher education. Nevertheless, among the limited works published, it is concluded that STEM projects based on educational robots, following education on sustainability approaches, would improve student’s skills and increase their motivation [13,14]. Researchers should point out that Bernardine Dias et al., in their work examine the potential intersections of robotics and its component technologies with education and sustainable development, and Sathiya et al., in their work, focus on the green design and development of mobile robots [15].

Education in industrial design and production is one of the primary pillars of economic development [16]. The students of the industrial design and production engineering university departments are trained to find solutions to issues related to industry and beyond. Through their education, they learn how to study a problem, analyze it, and propose and design feasible, applicable, and acceptable solutions [17]. For this purpose, many didactic approaches have been utilized including problem-oriented and problem-based learning, and recently STEM and Educational Robotics have become the new modern trends of teaching and learning, gaining popularity over the last few years due to their proven learning value even in the higher education [18,19]. STEM methods support students at all education levels to develop cognitive skills in critical thinking and problem-solving [20,21]. Nowadays it is crucial to embed sustainability and the Sustainable Design Goals (SDGs) into education in order to cultivate an innate sustainability mind-set and relevant competencies in students.

In the 1990s, the National Science Foundation (NSF) first introduced the SMET as a precursor to today’s STEM acronym, to describe learning and teaching in the fields of Science, Technology, Engineering, and Mathematics [22,23]. In the literature there are many different definitions of STEM; however, STEM is related to teaching and learning methods that integrate the content and skills of the terms that compose it [24,25]. STEM can be integrated into education via two different approaches:

• The content integration approach, which focuses on consolidating content areas into a single teaching activity to highlight “big ideas” from multiple content areas, and
• The contextual integration approach which focuses on content from a single scientific field, while also using frameworks from other disciplines in order to make the topic more relevant [26,27].

Educational Robotics is one such well-known STEM integration that is commonly used within and outside schools. It refers to technology platforms (e.g., robots and robot kits), educational resources (and programs), and learning theories. It has gained popularity over the last years due to the students’ involvement in undertaking challenges and learning outputs through the process of exploration, discovery, and invention using real problems and situations [25]. Both STEM and Educational Robotics share many of the same benefits [28,29,30,31,32,33,34,35,36,37]:

• They increase students’ motivation and curiosity.
• They encourage students to express new ideas, think differently, and problem solve.
• They encourage teamwork, cooperation, and socialization.
• They improve the learning experience and the students’ concentration.
• They develop students’ soft skills, such as teamwork, critical-thinking, creativity, problem-solving, and cognitive–social skills.
• They provide practical experiences with many scientific subjects, making them fun and attractive and retaining the students’ curiosity and attention.
• Eliminate stereotypes about gender roles, and bridge ethnic and gender differences.

To date, robots and, specifically educational robots are increasing in popularity in education. Their playful nature, together with their STEM integration into educational activities, transforms them into interesting learning tools. Although Educational Robotics can be “unplugged”, meaning that educational activities can be implemented without the necessity of educational robots, in most cases, an appropriate educational device (robot, robot kit) must be used for Educational Robotics. Today, a wide variety of such educational devices can be found in the retail market, distinguished into two basic categories: (i) programmable robots (e.g., Thymio, mBot, Edison, Ozobot, etc.), and (ii) robotics kits (e.g., Lego^®, Robotis, Makeblock, VEX, etc.). While these options meet the educational needs of K-12 students, in tertiary education, custom robots are usually used due to their advanced specifications, different teaching goals, and increased variety of possibilities in the context of the robot’s hardware and software [38]. Consequently, custom robots were introduced, into many university engineering courses as teaching and experimental tools for learning disciplines.

Custom robots are robots that are designed and built according to the needs that they are called upon to fulfill, bypassing the main limitations of commercial robots and robotic kits, such as the following [39]:

• Expensive—not affordable—robot cost;
• Limitations concerning expandability (not so many sensors, actuators available to add, absence of specialized sensors to use, etc.);
• Some of them use close-source robot architecture placing constraints on the further development of software/hardware by its community;
• Limitations concerning the robot’s shell and shape customization;
• Limitations concerning the robot’s accompanied software e.g., absence of different languages programming, or cooperation with specialized computer programs/software;
• Robots demand specialized hardware e.g., modern PCs, latest versions of operating systems, and sometimes Internet connection for programming.

While the didactic approaches of STEM and Educational Robotics are widely used in higher education and gaining popularity, it is most likely that they are “hidden” in the teaching context of a course such as in Mechatronics, Robotics, Automatic Control Systems, etc.

Mechatronics is defined as the intersection of mechanics, electronics, computers, and control [18,40]. Mechatronics is a new and growing field that combines different types of engineering practices to create robots and systems that can think and act on their own. It involves technical and non-technical skills like building and designing robots (mechanical engineering), designing and implementing circuits (electrical and electronic engineering), and using computer programs (computer software engineering) to make robots do what researchers want them to do [19]. Like STEM, the application of Mechatronics in education has been developed in many forms and contexts [18,41]. For instance, Alptekin et al. [42], and Amerongen et al. [43] pointed out the “integration” aspect of Mechatronics, and that should be a key teaching objective for any engineering curriculum. Furthermore, multiple studies [44,45,46,47,48,49] have already documented Mechatronics’ value in the interdisciplinary context of an engineering curriculum. As in STEM education, the didactic methods that are most suitable for Mechatronics education focus on the use of project-oriented and project-based learning [50,51,52,53,54,55,56]. This gives Mechatronics (similar to STEM) considerable appeal as a general-purpose educational tool for imparting general skills and competencies.

The Industrial Design and Production Engineering Department (IDPE) delivers an Industrial Design and Production Engineering degree after ten semesters of taught courses [17]. The subject of the department is the design of modern systems and services, creatively combining knowledge and methodologies from a broad spectrum of sciences, using new technologies for the design and production of innovative products, with the ultimate goal of increasing productivity and production and maintaining environmental sustainability [16]. In this way, its graduates must be capable of creatively using new technologies, science, and art to design solutions in the form of easy-to-use and functional products, processes, and systems in all productive sectors [16].

IDPE’s curriculum incorporates a Mechatronics course taught in the 7th semester. As noted above, Mechatronics is the intersection of multiple engineering disciplines, most of which are covered in specialized courses. Ιn the case of IDPE, the following courses are offered: Automatic Control Systems, Data Collection and Analysis, Robotics, Electronics, System and Signal Analysis, Microcontroller-Based System Design, and more [57]. However, none of these courses deals with an authentic, real-life problem, developing the problem-solving and team-working soft skills of the students, and nor do they introduce the aspect of the different technologies’ integration for designing integrated systems and devices. In this context, the team who is responsible for the delivery of the Mechatronics modules examined these requirements considering the literature and developed the Mechatronics courses based on STEM education principles and using Educational Robotics methodologies and practices.

In this direction, existing STEM and Mechatronics teaching models were used from the literature, resulting in the following adapted proposed model that best served the purposes of the Mechatronics course in the IDPE and met the following conditions [42,45,58]:

• The model must be adapted to the requirements of the IDPE curriculum.
• It has to be in line with other didactic models reported and used in the literature.
• It has to adopt a participatory way of teaching Mechatronics, where students have to develop their problem-solving approaches to the Mechatronics challenge given to them.
• It has to improve the students’ soft skills, including complex problem-solving skills, critical thinking, creativity, teamwork, coordination with others and management, judgment and decision-making, communication, etc.
• It has to foster active and motivated student participation.

The proposed theoretical model represents these factors and it comprises four stages. It was based on the literature [59,60,61,62], it is a modified model of Chatzopoulos’ framework [27], and it utilizes the Computational Thinking Skills Model in synergy with the Teacher Guidance Protocol [63]. The model’s four stages (Figure 1) are as follows [18]:

• Challenge. A complex problem is presented to the students with a specific goal to accomplish. While the project’s goal seems to be feasible, it is not so easy to achieve.
• Explore. The students must develop a problem-solving approach by decomposing and simplifying the problem into smaller manageable parts to find a solution. These parts are equally outsourced to the other members of the team. In this way, the team members can easily understand the parts and tasks that need to be done.
• Exchange. At this stage, the students communicate their knowledge and exchange views and solutions with fellow students, teaching staff, and peers. Also, the students manage the teamwork between them and with partners.
• Generalize. The students recognize task parts that are known and frequently lead to easier use (e.g., designing algorithms). Therefore, they use general pieces of learning as reusable parts of their tasks.

This model uses a circular process (called students’ loop), where the knowledge students gained from the last (Generalize) stage, can be useful to review and modify the problem under a new scope, feeding a new cycle (loop) of the model’s stages. This may be useful in the case where the completion of a full four-step student loop leads to the student being able to cope better with another project (Mechatronics assignment). In this way, the Generalize stage of the first loop feeds the Challenge stage of the second loop, and so on. In addition, this model specifies one more loop: the educator’s loop (Figure 2).

The educator’s loop is an outer loop that nests the student loop. It has the following four stages [18]:

• Review didactic goals,
• Introduce new means,
• Receive student’s feedback,
• Appraise results.

It was based on Atmatzidou’s Teacher Guidance Protocol [27,63], and used to develop students’ problem-solving and metacognitive skills.