RESEARCH, DESIGN AND DEVELOPMENT OF A DATA ACQUISITION UNIT FOR A ROOFTOP SOLAR ENERGY SYSTEM

Rooftop solar power systems play a vital role in Vietnam’s Net-Zero target by 2050. However, the lack of automatic monitoring systems remains a significant challenge for early detection of performance degradation. This study designed and fabricated a data acquisition unit based on Arduino Mega 2560 and ESP32. The device integrates multiple sensors to measure solar irradiance (INA219), DC voltage (isolated ES-K12), current (WCS1500), panel temperature (DS18B20), air temperature and humidity (SHT30), wind speed, and particulate matter (PMS5003). Field testing on a 3 kWp system over 3 months showed measurement errors of ±4.5% for irradiance, ±2.8% for voltage and current, and ±0.6°C for temperature. System efficiency ranged from 11.3% to 12.6% under irradiance of 560–985 W/m². The unit displayed data in real-time on HMI, stored on SD card, and transmitted via MQTT. The developed system provides a low-cost, stable, and practical solution for monitoring small-scale rooftop solar systems.