Design and Implementation of an Interactive Digital Twin Platform for Academic Buildings

This study presents the design and deployment of a classroom-scale Digital Twin platform for real-time monitoring of occupancy and indoor environmental quality in academic buildings. The system integrates low-cost Internet of Things sensor nodes, Message Queuing Telemetry Transport based communication, Node-RED middleware, and a linked 3D visualization interface to provide spatially contextualized building data. Environmental variables such as temperature, humidity, equivalent carbon dioxide, and light levels are continuously monitored alongside doorway-based occupancy estimation using time-of-flight sensors. The platform enables real-time visualization, historical analysis, and rule-based alerting within an interactive digital environment. Unlike many existing solutions that rely on proprietary infrastructure or privacy-sensitive sensing, the proposed system emphasizes affordability, modularity, and privacy-preserving design. The deployment across 26 classrooms in an academic building demonstrates the feasibility of integrating distributed sensing with spatial models for operational decision support. The results highlight both the potential and limitations of low-cost sensing in real-world academic environments.