A 3-Phase Energy Meter with Multicore Support Using an ESP32 MCU with Voltage and Current Sensors

To continuously monitor energy consumption in his home, and store and communicate the data wirelessly, Gamal built a 3-phase energy meter, using a single ESP32 MCU with dual-core architecture, and voltage and current sensors. In his novel design, one core senses voltage and current and calculates consumed energy, while the other, long-forgotten core handles the user's web requests, logs measurements on an SD card, and displays current, voltage, and cumulative power consumption.

- Gamal Labib

FIGURE 1 The exterior structure of the project. Top: three 7-segment 8-digit modules, each of which is allocated to a specific mains supply phase. Mid-right: an MCU reset red button, a yellow push button to display button. Mid-bottom: five LED indicators (from right)-Blink, Wi-Fi connectivity, 5V power supply, Activity, and External MCU power source (for example, Laptop's USB port). Bottom right: DC 5V jack, MCU power source selector switch, Continuous Display switch.

Understanding the energy consumption pattern of home appliances and gadgets is important for owners to optimize and to minimize their electricity bills. Keeping track of the official energy meter to identify our daily consumption may prove impractical, especially if the meter is installed outside the premises. I needed an inexpensive solution to adjust my electricity consumption and to estimate future bills.

FIGURE 2 The ZMPT101B voltage sensor module (left) and SCT-013 60A/1V current sensor transformer (right).

I came across many energy meter projects based on microcontrollers (MCUs) and sensor modules, but they mostly focused on single-phase mains power supplies. Since I have 3-phase mains, I would then require three homemade meters and offline analysis of their readings to manage my consumption. In this project, I consolidate the mains supply monitoring for my home into a single MCU-based meter for which I can embed all analysis code once, and control it within my home Internet of Things.