Real-Time IoT Temperature Monitoring Using Xiaomi Mijia BLE, ESP32, MQTT, and EMQX

Andicho Haryus Wirasapta (Electrical Engineering Study Program, Electrical and Informatics Engineering Department, Universitas Jambi, Jambi, Indonesia)
Tiara Deta Pamungkas (Nursing Study Program, Nursing Department, Politeknik Kesehatan Kementerian Kesehatan Jambi, Jambi, Indonesia)

Journal of Applied Electrical Engineering
Vol. 10 No. 1 (2026): JAEE, June 2026

This paper proposes a low-cost IoT-based real-time temperature and humidity monitoring system as a Bluetooth Low Energy (BLE) to MQTT bridge using an ESP32 microcontroller, Xiaomi Mijia LYWSD03MMC sensor, and EMQX broker. The key novelty of this work lies in the quantification of end-to-end communication performance of a BLE–Wi-Fi–MQTT bridge architecture using commercial off-the-shelf components. Five repeated measurement trials were conducted to evaluate system performance. Results show a mean end-to-end latency of 318 ms (standard deviation: 16,4 ms, max: 342 ms), a packet delivery ratio of 99,6%, and a sensor accuracy of RMSE=0,22°C against a calibrated digital reference thermometer. The system operated continuously for 48 hours with 99,6% uptime and a single automatic reset. Compared to HTTP-based counterparts, the proposed BLE–MQTT bridge achieves 36,6% lower latency. These results confirm the feasibility of integrating proprietary BLE sensors into mainstream MQTT-based IoT platforms using a lightweight and replicable architecture.