Development of an Internet of Things Smart Electricity Meter Using MQTT Protocol

Abstract

 This research presents the development of an Internet of Things based Smart Meter with the ability to measure and
report over the Internet not only voltage, current and power, but also power factor of connected load on two electric buses and it
keeps historical data for future use. The historical data of power usage is accessible to the Power Supply Company and the
Consumer. The smart meter has an LCD display and reports measurements using the Message Queuing Telemetry Transport
protocol over a secured wireless internet connection. Home Assistant provides the necessary cloud-based user interface which
displays real-time readings updated every few seconds from the meter as well as stores measurements over a period. The smart
meter employs the ESP32 microcontroller with voltage and current sensors connected to its Analog to Digital Converter pins. Two
methods, namely the peak method and root mean square (RMS) method were investigated for the measurement of the voltage
and current on the busses. Other parameters like frequency, power and power factor were calculated in software routines
implemented by the microcontroller. The meter was calibrated using a Fluke digital Multimeter. The smart meter performed reliably
with an accuracy of +/- 3% when using the peak method of measurement. This was further improved to +/- 1% when the RMS
method of measurement was employed