This paper deals with an integration of STEM education and project-based learning (PBL) by introducing a hybrid hardware/software-based learning platform covering eight learning units. PBL not only bridges the gap between theory and practice, but also focuses on improving students' soft skills, which is important as they prepare for further education or the job. The proposed STEM learning platform combines power electronics, digital communications and informatics by using the novel talkative power conversion (TPC) concept as a common framework, providing a multidisciplinary approach with relevance to society. Young people have a unique chance to learn fundamentals of these areas as well as acquiring practical skills by implementing these principles in hands-on experiments. The level of difficulty is adjustable so that the learning platform is suitable for both pupils at high school as well as university students. In this paper, the learning units are adapted to the abilities of pupils in their last two high school years, subsequently referred to as high school seniors.