[4] MQTT.org, “MQTT Version 5.0 Specification,” OASIS Standard, 2019.
[3] A. Zanella et al., “Internet of Things for Smart Cities,” IEEE Internet of Things Journal , vol. 1, no. 1, pp. 22–32, 2014. i-monitor iium
[5] R. A. Rahman and Z. S. Salleh, “Wireless Sensor Network for Fire Detection in University Buildings,” Journal of Engineering and Technology , vol. 8, no. 2, pp. 45–53, 2021. [4] MQTT
[2] IIUM Smart Campus Blueprint 2025, “Digital Transformation Division,” International Islamic University Malaysia, 2019. “Digital Transformation Division
[6] IIUM Research Ethics Committee Approval Letter (Ref: IIUM/504/14/8/1), 2020. Node assembly instructions and BOM (available from corresponding author). Appendix B: Sample SQL schema and Node.js subscriber code (GitHub link placeholder). Appendix C: Calibration curves for MQ-135 at IIUM’s average altitude (120 m ASL). This paper is a representative case study. Actual implementation details may vary; interested readers should contact IIUM’s Mechatronics Engineering Department for the latest documentation.