Introduction: The Need for Smart Energy Monitoring

Electricity is the backbone of every modern home, yet most people have no idea how much power their appliances consume until the bill arrives. With an ESP32-based Smart Energy Monitor, you can measure, visualize, and understand your real-time energy usage — all from your smartphone or laptop.

This project by SP Tech Solutions shows how to create a simple but powerful IoT-based energy tracker using a current sensor, voltage calculation, and a live web dashboard.

Why This Project Matters

  • Monitor appliance-level energy usage
  • Detect unusual power consumption early
  • Log data for energy optimization and automation
  • Prevent overloads and reduce electricity waste

Required Components

  • ESP32 Development Board
  • ACS712 Current Sensor
  • 16x2 LCD with I2C or OLED Display
  • Jumper wires and breadboard
  • 5V Power Supply

How It Works

The ACS712 sensor measures current by detecting the magnetic field generated by the current flow. The ESP32 reads this analog voltage, calculates the RMS current, multiplies it with the line voltage (230V), and computes real-time power usage. This data can then be displayed locally or uploaded to a cloud platform for long-term monitoring.

Circuit Overview

ACS712 VCC → 5V  
ACS712 GND → GND  
ACS712 OUT → ESP32 GPIO34 (ADC pin)  
OLED SDA → GPIO21  
OLED SCL → GPIO22

Code Summary

This simplified sketch measures current and displays real-time power readings on the OLED screen and serial monitor. It uses the Adafruit_SSD1306 and Adafruit_GFX libraries.

// SP Tech Solutions - Smart Energy Monitor
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SENSOR_PIN 34
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

void setup() {
  Serial.begin(115200);
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.println("SP Tech Energy Monitor");
  display.display();
}

void loop() {
  float sensorValue = analogRead(SENSOR_PIN);
  float current = (sensorValue - 2048.0) * (5.0 / 4095.0) / 0.066; // ACS712 30A
  float power = abs(current * 230.0);

  display.clearDisplay();
  display.setCursor(0, 10);
  display.print("Current: "); display.print(current, 2); display.println(" A");
  display.print("Power: "); display.print(power, 1); display.println(" W");
  display.display();

  Serial.printf("Current: %.2f A | Power: %.1f W\n", current, power);
  delay(1000);
}

How to Expand

  • Send data to a cloud dashboard like ThingSpeak or Blynk
  • Add Wi-Fi web interface for local monitoring
  • Log data to SD card for offline analysis
  • Set alerts for overcurrent or abnormal usage

Common Issues

  • Fluctuating readings: Use averaging or RMS calculation.
  • Zero drift: Calibrate the sensor offset around 2048 ADC value.
  • Display not working: Check I2C address using I2C Scanner sketch.

Applications

  • Smart home energy dashboards
  • Industrial machine load monitoring
  • Solar energy management systems
  • IoT-enabled energy optimization platforms

Conclusion

This ESP32-based Smart Energy Monitor offers a practical way to gain visibility into your energy usage. Once deployed, you’ll start noticing patterns — and opportunities to save power and optimize consumption.

For pre-calibrated sensor kits, premium ESP boards, and advanced IoT modules, visit SP Tech Solutions. We provide everything you need to build smarter, greener systems.

SP Tech Solutions — Engineering Efficiency for a Sustainable Future ⚡