#include <LiquidCrystal_I2C.h>

// Define the LCD module
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Set the voltage divider resistors values
const float R2 = 1000.0; // Resistance value of R1 in ohms
const float Vin = 5.0;    // Input voltage to the voltage divider in volts

void setup() {
  // Initialize the LCD module
  lcd.begin();
  lcd.backlight();
  lcd.print("Voltage Divider");
  lcd.setCursor(0, 1);
  lcd.print("R =         Ohms");
}

void loop() {
  // Read the voltage across the resistor R2
  float Vout = analogRead(A0) * Vin / 1023.0;

  // Calculate the resistance R2 using the voltage divider formula
  float R1 = abs(-(R2 * (Vin - Vout)) / Vout);


  // Display the calculated resistance R2 on the LCD
  lcd.setCursor(4, 1);
  lcd.print("        ");
  lcd.setCursor(4, 1);
  lcd.print(R1);
  delay(500);
}