## 1 Introduction  
Single-board computers (SBC), as an affordable and open connected platform, revolutionized the areas of measurement and automation soon after their appearance in 2012 [1]. Experimental work in chemistry education was no exception, and there are many articles describing SBC-based devices that were built to support laboratory instruction [2; 3; 4; 5]. The establishment of the Raspberry Pi foundation, as a charity promoting the educational value of their products, helped spread the idea of using a small, inexpensive, connected computer in various scientific and educational setups [6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18; 19; 20; 21; 22; 23]. Several authors have researched and recognized the potential of using SBCs in chemistry-driven integrated Science, Technology, Engineering, and Mathematics (STEM) education. For example, [PERSON] and [PERSON] [24] had undergraduate students build a UV\(-\)vis spectrophotometer and found a significant improvement in the students' knowledge of spectrophotometers compared to the control group. [PERSON] et al. [25] managed to reduce the black-box effect of using chemistry-laboratory instruments by engaging chemistry students in designing and optimizing an absorbance spectrometer. They argue that building a chemistry device offers multiple learning possibilities. For example, it is a good context to teach analytics skills, such as calibration and determination of the limits of linearity and dynamic range, and, at the same time, demonstrate the iterative nature of scientific research and the instrumental side of chemistry. In addition, to improved content knowledge, this kind of integrated STEM project has the potential to support learning motivation, and the development of versatile problem-solving skills by introducing engineering-type thinking. Other research identified the challenges that educators face when trying to engage students in integrated STEM projects, such as an open SBC project. The most important challenge is related to the diversity of the required knowledge both from teachers and students in multidisciplinary learning environments and the limited resources available in real-life teaching situations [26, 27]. To implement engineering design in chemistry-driven STEM education, teachers need an understanding of engineering processes and adequate resources for building SBC-based setups. Another challenge is pedagogical--how to secure an active role for students and maintain it during the whole course? [28, 29, 30]. A possible solution to these challenges is to apply the so-called engineering approach to designing educational devices and experiments. This approach is a systematic way to design, test, and build devices and experiments [31, 32]. It makes it possible to control complex design settings and involves students in the design process as active stakeholders. From several design methods of engineering and design cycles, we chose the function-and-functionality matrix method [32]. The method was originally designed for the field of engineering, but there is no doubt that many fields can benefit from a systematic design framework. By using the engineering approach, a chemistry educator, who is not entirely familiar with engineering, can incorporate engineering and design thinking into STEM education in a coherent manner that has the potential to support learning. Therefore, the aim of this research is to explore what kind of opportunities and challenges the engineering approach initiates when it is implemented in chemistry teacher education in the SBC context. The purpose of the paper is to present good practice examples for all educators interested in applying SBC to strengthen the engineering in chemistry driven STEM education. Analyzing the opportunities and challenges helps address the support needs of the future chemistry teachers developing an SBC-based experiment using an engineering approach.