// to the pins used:
const int  analogInPin = A0;  // Analog input pin that the potentiometer is attached to
const int  analogOutPin = 3; // Analog output pin that the LED is attached to
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 20, 4);

int   sensorValue = 0;        // value read from the pot
int   outputValue = 0;        // value output to the PWM (analog out)
float  V = 0;
void setup() {
  // initialize serial communications at 9600 bps:
  Serial.begin(9600);
}

void loop() {
  // read the analog in value:
  sensorValue = analogRead(analogInPin);
  // map it to the range of the analog out:
  outputValue = map(sensorValue, 0, 1023, 0, 255);
  // read the analog in value:
   V  = float(map (outputValue , 0, 255, 0, 500))/100;
  // change the analog out value:
  analogWrite(analogOutPin, outputValue);

  // print the results to the serial monitor:
  Serial.print("sensor = " );
  Serial.print(sensorValue);
  Serial.print(" output = ");
  Serial.print(outputValue);
  //Serial.print("\t V = ");
  Serial.print(" Volt = ");
  Serial.println( V );
  lcd.init();
  lcd.backlight();
  lcd.setCursor(1,0);
  lcd.print("Volt = ");
  lcd.print(V);

  // wait 200 milliseconds before the next loop
  // for the analog-to-digital converter to settle
  // after the last reading:
  delay(200);
}