A Practical Implementation of RESTful API and WebSocket Protocol for Power Efficiency Monitoring: A Case Study at Muhammadiyah Orphanage

¹ Department of Electrical Engineering, Faculty of Engineering, Universitas Muhammadiyah Yogyakarta, Bantul City 55183, Indonesia
² Center of Artificial Intelligence and Robotic Studies, Research and Innovation Institute, Universitas Muhammadiyah Yogyakarta, Yogyakarta, Bantul City 55183, Indonesia
³ Department of Computer Science and Information Engineering, College of Information and Electrical Engineering, Asia University, Taichung City 41354, Taiwan
⁴ Department of Medical Research, China Medical University Hospital, China Medical University, Taichung City 41354, Taiwan

Abstract

Power efficiency needs to be monitored to avoid adverse effects on electricity users, particularly those with significant inductive loads. However, current monitoring devices are limited in their ability to continuously record data and represent outputs effectively. This study designs an IoT-based reactive power and power factor monitoring system using a RESTful API for electrical equipment at a Muhammadiyah orphanage. The proposed system utilizes the PZEM-004T as the power sensor, the ESP32 microprocessor as the data processing unit, and a web server as the interface for settings and data visualization. Measurement records for reactive power and power factor can be stored in internal data storage. Additionally, remote monitoring can be conducted via WebSocket protocol and the Telegram application. The system has been tested by comparing reactive power, power factor, kWh, and cost with a standard power meter. The results demonstrate that the sensor exhibits an error of 9.02% in current measurement and 1.106% in active power measurement, with an average delay of 0.137 seconds via WebSocket-based server and 1.359 seconds using Telegram application.