#include<LiquidCrystal_I2C.h>

LiquidCrystal_I2C  lcd(0x27,20,4);

int gauge;

char buffer[40];

byte gauge_left[8] =   {B11111, B10000, B10000, B10000, B10000, B10000, B10000, B11111};
byte gauge_center[8] = {B11111, B00000, B00000, B00000, B00000, B00000, B00000, B11111};
byte gauge_right[8] =  {B11111, B00001, B00001, B00001, B00001, B00001, B00001, B11111};
byte gauge_filled[8] = {B11111, B11111, B11111, B11111, B11111, B11111, B11111, B11111};

void setup() 
{
     lcd.init();  
     lcd.backlight();

     
     lcd.createChar(0, gauge_left);
     lcd.createChar(1, gauge_center);
     lcd.createChar(2, gauge_right);
     lcd.createChar(3, gauge_filled);
      
     
}

void loop() 
{
      lcd.setCursor(0,0);

      sprintf(buffer,"Progress%3d%%", gauge); //put text to print in buffer. %3d for 3 digit.   %% for display % symbol
      lcd.print(buffer);                      //clear 3 digit from screen. Maximum number is 100 
      
 

      float gauge_step = 100./8.0;           //calculate value of each block  100/8 = 12.5  
                
      for(int i=0; i<8; i++)                 //loop through each block with current value of gauge
      {          
        if(gauge < gauge_step * i)           //1st block max val < 12.5, 2nd block max  < 25
        {          
           if(i == 0)                        //if first block, display left
           {          
              lcd.write(0);                  
           }          
           else if (i == 7)                  //if last block, display right
           {          
              lcd.write(2);          
           }          
           else          
           {          
              lcd.write(1);                  //display center (empty only top bar and botom bar)
           }          
        }          
        else          
        {          
           lcd.write(3);                    //display filled 
        }
      }

      gauge+=1;

      if(gauge >100)
      {
         gauge = 0;
      }

      delay(500);

}