Energy-Efficient Data Acquisition and Control System using both LoRaWAN and Wi-Fi Communication for Smart Classrooms

This manuscript presents a novel hybrid Internet of Things (IoT) system for data collection and potential sustainable energy management in classrooms. The proposed system utilizes low-cost microcontrollers and sensors to monitor environmental parameters like temperature, humidity, luminosity, and environmental acoustic noise. The data transmission leverages a hybrid approach, employing both LoRaWAN for long-range communication and Wi-Fi for shorter distances. Notably, the system prioritizes LoRaWAN for energy efficiency and incorporates a backup Wi-Fi connection for redundancy and also for Over-The-Air (OTA) firmware upgrades. Considering the size (approximately 60 acres) and scattered buildings of the University of West Attica campus, only 3 LoRaWAN Gateways are needed for comprehensive coverage. In contrast, achieving the same coverage with Wi-Fi would require roughly 20 routers. This highlights the primary use of LoRaWAN for the proposed IoT system. The experimental setup involved deploying the system in a classroom at the University of West Attica. The collected data is stored in a time-series database and visualized using open-source software like Grafana. The results demonstrate the system's effectiveness in data acquisition and highlight its potential for facilitating autonomous control of lighting, heating and cooling systems based on the gathered environmental data. This approach contributes to sustainable energy management by enabling the optimization of energy consumption in classrooms. Additionally, the utilization of low-cost components and many open-source software like ChrirpStack, Mosquitto MQTT Broker, Node-RED, InfluxDB, Telegraf and Grafana promotes wider adoption and fosters community collaboration. The proposed system serves as a valuable tool for promoting ecological practices and achieving sustainability in educational institutions and similar public spaces.