#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Define the I2C LCD
LiquidCrystal_I2C lcd(0x27, 16, 2); // Change the address if needed

// Define the potentiometer pin
const int potPin = A0;

// Define the LED pin
const int ledPin = 2;

// Define the resistor value in ohms
const float resistorValue = 100.0;

void setup() {
  Serial.begin(9600);
  
  // Initialize the I2C LCD
  lcd.init();
  lcd.backlight();
  
  // Initialize the LED pin
  pinMode(ledPin, OUTPUT);
  
  // Clear LCD
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Power Calculation");
}

void loop() {
  // Read the voltage from the potentiometer
  int sensorValue = analogRead(potPin);
  float voltage = sensorValue * (5.0 / 1023.0);

  // Calculate current (Ohm's law: I = V / R)
  float current = voltage / resistorValue;

  // Calculate power (P = V * I)
  float power = voltage * current;

  // Display values on LCD
  lcd.setCursor(0, 1);
  lcd.print("V: " + String(voltage, 2) + "V ");
  lcd.setCursor(8, 1);
  lcd.print("I: " + String(current, 4) + "A ");
  lcd.setCursor(0, 0);
  lcd.print("P: " + String(power, 4) + "W  ");

  // Turn on/off LED based on voltage
  if (voltage > 4.0) {
    digitalWrite(ledPin, LOW); // Turn on the LED
  } else {
    digitalWrite(ledPin, HIGH); // Turn off the LED
  }

  // Print values to Serial Monitor
  Serial.print("V: ");
  Serial.print(voltage, 2);
  Serial.print("V, I: ");
  Serial.print(current, 4);
  Serial.print("A, P: ");
  Serial.print(power, 4);
  Serial.println("W");

  // Delay for stability
  delay(1000);
}