Smart Energy Meter

Smart Energy Meter uses ESP32 for data collection and WiFi, and Raspberry Pi Pico for calculations, with LCD display and Blynk app access.

IntermediateFull instructions provided3 hours13

Things used in this project

Hardware components

Espressif ESP32

Reads the analogue voltage and current signals from the sensors and manages Wi-Fi communication to send data to the Blynk cloud.

ACS712 Current Sensor

Raspberry Pi Pico

Receives the raw voltage and current data from the ESP32 via UART and performs the calculations for energy.

Adafruit RGB Backlight LCD - 16x2

Software apps and online services

Arduino IDE

Story

Energy monitoring systems are essential in modern electrical

engineering because they allow users to measure, analyse, and

optimize electricity consumption. Traditional energy meters only

display total energy usage and do not provide real-time monitoring or

remote access.

In this project, we built a simple Smart Energy Meter that can:

• Measure voltage

• Measure current

• Calculate power

• Calculate total energy used

• Show values on an LCD

• Send data to the Blynk mobile app

This project presents the design and implementation of a Smart

Energy Meter capable of measuring electrical parameters and

displaying them remotely using Internet of Things (IoT) technology.

The system uses an ESP32 microcontroller for data acquisition and

wireless communication, while a Raspberry Pi Pico performs

calculations related to electrical power and energy consumption. The measured data is transmitted to the Blynk IoT platform, allowing

real-time monitoring on smartphones, computers, and other internet-

connected device

Circuit Diagram of Smart Energy Meter using ESP32 and Raspberry Pi Pico with ACS712 Sensor and I2C L

The connections between components are as follows:
1. Sensors to ESP32: The output of the voltage divider and
the ACS712 sensor are connected to two separate analogue
input pins on the ESP32.
2. ESP32 to Pico (UART):
o ESP32 TX (GPIO Pin) → Pico RX (UART0 Pin)
o ESP32 RX (GPIO Pin) → Pico TX (UART0 Pin)
o Common GND is established between the two
microcontrollers.
3. ESP32 to LCD: The I2C pins of the ESP32 (SDA, SCL)
are connected to the corresponding pins on the 16x2 LCD
module.
4. Load: The resistive load is connected in series with the
ACS712 sensor to complete the circuit.

Code

Smart Energy Meter Using ESP32 and IoT (Blynk Integration)

#define BLYNK_TEMPLATE_ID "TMPL3yAB0NCai"
#define BLYNK_TEMPLATE_NAME "Smart Energy Meter"
#define BLYNK_AUTH_TOKEN "z49QQ1StrgNb2F2ogQIeF-6y3TwBMWTp"
#define BLYNK_PRINT Serial
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <WiFi.h>
#include <BlynkSimpleEsp32.h>
// WiFi
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Smart Energy Meter
char ssid[] = "2Sixty3";
char pass[] = "Last5050!";
// LCD
LiquidCrystal_I2C lcd(0x27, 16, 2);
// Sensor Pins
#define VOLTAGE_PIN 34
#define CURRENT_PIN 35
// Variables
float voltage = 0;
float current = 0;
float power = 0;
float totalEnergy = 0;
float avgVoltage = 0;
float peakCurrent = 0;
float cost = 0;
int overload = 0;
void setup() {
Serial.begin(115200);
Serial2.begin(9600, SERIAL_8N1, 16, 17); // RX=16 TX=17
Wire.begin(21, 22);
lcd.init();
lcd.backlight();
lcd.setCursor(0,0);
lcd.print("Connecting...");
Blynk.begin(BLYNK_AUTH_TOKEN, ssid, pass);
lcd.clear();
lcd.setCursor(0,0);
lcd.print("Smart Energy");
lcd.setCursor(0,1);
lcd.print("Meter Ready");
delay(2000);
lcd.clear();
}
void loop() {
Blynk.run();
// 🔹 Read Sensors
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Smart Energy Meter
int rawVoltage = analogRead(VOLTAGE_PIN);
int rawCurrent = analogRead(CURRENT_PIN);
voltage = (rawVoltage * 3.3) / 4095.0;
current = (rawCurrent * 3.3) / 4095.0;
// 🔹 Send to Pico
Serial2.print(voltage);
Serial2.print(",");
Serial2.println(current);
// 🔹 Receive from Pico
if (Serial2.available()) {
String data = Serial2.readStringUntil('\n');
int p1 = data.indexOf(',');
int p2 = data.indexOf(',', p1+1);
int p3 = data.indexOf(',', p2+1);
int p4 = data.indexOf(',', p3+1);
int p5 = data.indexOf(',', p4+1);
if (p5 > 0) {
power = data.substring(0, p1).toFloat();
totalEnergy = data.substring(p1+1, p2).toFloat();
avgVoltage = data.substring(p2+1, p3).toFloat();
peakCurrent = data.substring(p3+1, p4).toFloat();
cost = data.substring(p4+1, p5).toFloat();
overload = data.substring(p5+1).toInt();
}
}
// 🔹 LCD DISPLAY (UPDATED ONLY THIS PART)
static int screen = 0;
lcd.clear();
if (screen == 0) {
lcd.setCursor(0,0);
lcd.print("Voltage:");
lcd.print(voltage,2);
lcd.print("V");
lcd.setCursor(0,1);
lcd.print("Current:");
lcd.print(current,2);
lcd.print("A");
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Smart Energy Meter
}
else if (screen == 1) {
lcd.setCursor(0,0);
lcd.print("Power:");
lcd.print(power,2);
lcd.print("W");
lcd.setCursor(0,1);
lcd.print("Energy:");
lcd.print(totalEnergy,3);
lcd.print("Wh");
}
screen++;
if (screen > 1) screen = 0;
// 🔹 Send to Blynk
Blynk.virtualWrite(V0, voltage);
Blynk.virtualWrite(V1, current);
Blynk.virtualWrite(V2, power);
Blynk.virtualWrite(V3, totalEnergy);
Blynk.virtualWrite(V4, avgVoltage);
Blynk.virtualWrite(V5, peakCurrent);
Blynk.virtualWrite(V6, cost);
Blynk.virtualWrite(V7, overload);
delay(1000);
}