Modular Open-Source Stirred Tank Reactor (MOSTR), an Internet of Things (IoT) system for engineering education

This paper presents the Modular Open-Source Stirred Tank Reactor (MOSTR), an IoT-enabled system developed for teaching chemical engineering principles such as residence time distribution, flow balancing and process instrumentation within higher education laboratories. Developed as a low-cost and pedagogically informed alternative to commercial units, the MOSTR's modular design allows for the simultaneous deployment of multiple rigs to enhance student engagement and inclusivity in practical learning at scale. The reactor integrates an M5Stack-based control unit with flow, temperature, and conductivity sensing, supported by real-time data streaming via Wi-Fi and Virtual Machine (VM) server infrastructure. The design emphasizes reproducibility through accessible fabrication techniques, such as 3D printing and prioritises both maintainability and pedagogical alignment. Characterisation tests demonstrate that the system is highly sensitive to mixing variations and modular configurations, which highlights its versatility for diverse educational experiments. To support global adoption and adaptation in open engineering education, all design files, software, and documentation are shared under CC BY 4.0 and MIT licenses.