DC Voltmeter

/* 
   PROJECTSDUNIA
   " DC Votmeter using ARDUINO "
   Designed By Sachin Jaiswal
   In this we measure the input voltage and display it on the 16 * 2 LCD Module
   For Full Description Visit http://projectsdunia.blogspot.com
*/

#include <LiquidCrystal.h>

LiquidCrystal lcd(12, 11, 5, 4, 3, 2);   // initialize the library with the numbers of the interface pins
float vin=0.0;
float temp=0.0;
float r1=100000.0;                       // Set the value of resister R1
float r2=10000.0;                       // Set the value of resister R2

void setup() {
  Serial.begin(9600);
  lcd.begin(16, 2);                    // set up the LCD's number of columns and rows: 
  lcd.print("PROJECTSDUNIA");     // Print a message to the LCD.
  delay(1000);
  lcd.clear();
  lcd.print("DC VoltMeter");
}

void loop() {
  int analog_val=analogRead(A0);      // read the value of analog pin A0 and store it in the variable analog_val
  temp = (analog_val * 5.0)/1024.0;   
  vin = temp/(r2/(r1+r2));
  if(vin<0.1)
  {
    vin=0.0;
  }
  lcd.setCursor(0, 1);        // set the cursor to column 0 line 1
  lcd.print("Voltage = ");    // print the voltage
  lcd.println(vin);
  delay(300);
}