#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Set the LCD address to 0x27 for a 16 chars and 2 line display
// If it doesn't work, try the address 0x3F. There are scripts online to dump the list
// of connected I2C devices (just google them), which will help you.
LiquidCrystal_I2C lcd(0x27, 16, 2); 


void setup()
{
  // initialize the LCD
  
lcd.begin();

  // Turn on the blacklight and print a message.
  
lcd.backlight();
  lcd.setCursor(0,1);
  lcd.print("Initializing...");


}

void loop()

{

  char mybuffer1[16]; // working variable
  char mybuffer2[16]; // working variable

 
  // ========= 1) read value on pin ============
  
  float FS = 10; // [Torr] (full scale)
  
  int   gauge_value_int   = analogRead(A0);         // read value from baratron
  
  float gauge_value_float = gauge_value_int/1023.0; // cast value to float going from 0 to 1
  float Volt              = gauge_value_float*5;    // voltage  

  float press_Torr        = gauge_value_float*FS;   // find the pressure, in Torr  
  float press_Pa          = press_Torr * 133.322;

  // ========= 2) write on LCD display ============
  
  char str1[15];
  char str2[15];
  dtostrf(press_Torr,5,3,str1);
  dtostrf(press_Pa,5,2,str2);
  sprintf(mybuffer1,"%s [Torr]", str1);  
  sprintf(mybuffer2,"%s [Pa]",   str2);  

  lcd.clear();
  lcd.setCursor(0,0);  
  lcd.print(mybuffer1);

  lcd.setCursor(0,1);
  lcd.print(mybuffer2);
  
  delay(400);

}