#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

int Vin=5;        //voltage at 5V pin of arduino
float Vout=0;     //voltage at A0 pin of arduino
float R1=3300;    //value of known resistance
float R2=0;       //value of unknown resistance
int a2d_data=0;    
float buffer=0;            

void setup() {
  pinMode(0, INPUT);

  lcd.init();
  lcd.backlight();

  lcd.setCursor(3,0);
  lcd.print("Ohm Meter");
  lcd.setCursor(0,1);
  lcd.print("R2 Value=");
  Serial.begin(9600);
}

void loop() {
  a2d_data=analogRead(0);
  Serial.println(a2d_data);

  buffer=a2d_data*Vin;
  Vout=(buffer)/1024.0;
  buffer=Vout/(Vin-Vout); 
  R2=R1*buffer;

  lcd.setCursor(10,1);
  lcd.print(R2);
}