Open-source hardware design and construction of a modular robotics kit for STEM education

Commercial educational kits for technology instruction often operate as closed "black boxes," presenting high import costs that limit their adoption in developing regions such as South America. This work presents an open-source, 5-module modular experimentation kit designed for STEM education in embedded systems and automation. Centered around an Arduino UNO core, the kit features progressive difficulty levels across five distinct modules: an environmental smart pot, an automated parking lot, an electromechanical drawbridge, a timed food dispenser, and a high-density home automation hub. The physical infrastructure combines low-cost FDM 3D printing with single-layer custom PCBs developed in Altium Designer. The total hardware cost is approximately $548.00 USD, optimized for localized manufacturing. Field validation with 40 s ondary school students in Cuenca, Ecuador, over a station-based collaborative rotation workshop demonstrated 100% hardware reliability under continuous operation. Quantitative post-workshop evaluations using a 5-point Likert scale indicated notable student engagement, curiosity, and positive motivation towards automation engineering concepts across all design modules. Complete parametric CAD files, manufacturing-ready Gerbers, firmware, and user manuals are fully open-access to promote global educational replication.