// include the library code:
#include <LiquidCrystal.h>
const int rs = 12, en = 11, d4 = 5, d5 = 4, d6 = 3, d7 = 2;
// initialize the library by associating any needed LCD interface pin
// with the arduino pin number it is connected to
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

float R1 = 1;
float R2 = 1;
int via = 0;
float vi, vo;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  Serial.println(" ");
  // set up the LCD's number of columns and rows:
  lcd.begin(16, 2);
}

void voltage() {
  // via = Serial.read();
  // via=analogRead(A5); //Input Analog Voltage
  via = 512;
  vi = map(via, 0,1023, 0,500) / 100.0; //Input Voltage
  // float viaf = via * 0.01;
  // float vi=(5*viaf)/1023; //Voltage
  vo=((R1+R2)/R2)*vi;
  Serial.println(vi);
  Serial.print(vo);
  Serial.println(" V");
}

void display() {
  /*
  The circuit:
 * LCD RS pin to digital pin 12
 * LCD Enable pin to digital pin 11
 * LCD D4 pin to digital pin 5
 * LCD D5 pin to digital pin 4
 * LCD D6 pin to digital pin 3
 * LCD D7 pin to digital pin 2
 * LCD R/W pin to ground
 * LCD VSS pin to ground
 * LCD VCC pin to 5V
 * 10K resistor:
 * ends to +5V and ground
 * wiper to LCD VO pin (pin 3)

*/
  // set the cursor to column 0, line 1
  // (note: line 1 is the second row, since counting begins with 0):
  lcd.setCursor(0, 0);

  // Print a message to the LCD.
  lcd.print(vo);
  lcd.print(" V");
}
void loop() {
  // put your main code here, to run repeatedly:
  voltage();
  display();
  delay(1000);
}