Technological development continues at a rapid pace and STEM (Science, Technology, Engineering and Mathematics) are becoming increasingly important subjects in the world of education. In this case, several problems were found that could be raised, namely how to design the development of media trainers that are interesting, interactive and practical, how to carry out validation and calibration before implementation and how effective the media trainers are that are implemented. The aim of this research is that it is hoped that the media trainer can help students and teachers so they can create interesting, interactive and practical teaching by carrying out validation before the workshop begins so that it is hoped that this IoT media trainer can help with effectiveness in its implementation. By using the Research and Development (R&D) method, the author develops previous research. It is hoped that this media trainer can help students in more interactive teaching by understanding IoT concepts and using sensors easily without having to use coding. In the first test, namely individual tool validation, the error results were no more than 1%. After that, the media trainer was tested with experts and got a score of 94 and got very decent criteria. After that, the researcher validated the tool test together with the teacher and got an average score. 88.88 and get very decent criteria. After testing, the researchers conducted a workshop, but before that the researchers conducted a pretest and after the workshop conducted a posttest, after that the researchers also conducted tests in groups. After conducting the workshop, the researcher gave questionnaires to students and teachers where the students' questionnaire results got an average of 85.18 and got very interesting criteria and the teachers' questionnaire results got an average of 92 and got very effective criteria. From all the data obtained, it can be stated that the research is considered valid, interesting, interactive and practical.
Keywords: STEM, Media Trainer, Internet of Things, Sensor, SMP Alam Cimanggis