DIY Power Consumption Monitoring Device using ESP32

The DIY Power Consumption Monitoring Device measures electrical parameters of household appliances by safely sampling both alternating voltage and current from a 220V AC mains line. Power flows into the system via the male 3-pin AC socket and passes through to the female 3-pin AC socket where the target appliance plugs in. Inside the device, a Hi-Link 5V 3W Switch Mode Power Supply (SMPS) steps down the high-voltage AC mains into a stable 5V DC supply required to power the ESP32 DevKit v1 and its attached sensors. To measure voltage, the ZMPT101B voltage sensor safely isolates and scales down the high-voltage AC input into a safe, proportional analog voltage signal that the ESP32 can read. Concurrently, the ACS712 current sensor monitors the electrical current passing through the live wire using a Hall effect-based method, outputting an analog voltage level relative to the load current. Both sensor signals are processed by the ESP32 microcontroller using dedicated software libraries like the ZMPT101B and ACS712 libraries to compute real-time power metrics such as wattage and energy consumption. Finally, the calculated data is visually rendered onto a compact 0.96-inch 128x64 OLED display communicating via the I2C protocol, utilizing the Adafruit GFX and SSD1306 libraries to present clear text and graphics. All electronic components are securely housed within a protective 3D-printed casing to ensure safe operation.