#include <LiquidCrystal_I2C.h>

#define echoPin 7
#define trigPin 6

#define pinR 11

#define I2C_ADDR    0x27
#define LCD_COLUMNS 20
#define LCD_LINES   4


LiquidCrystal_I2C lcd(I2C_ADDR, LCD_COLUMNS, LCD_LINES);


void setup() {

  pinMode(pinR, OUTPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  lcd.begin(16, 2);

}
void loop() {


  int distance = calDistance();

// Check the distance  and display  a message accordingly 
  if(distance > 40 ){ 

    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Refill Now!");
    lcd.setCursor(0, 1);
    lcd.print("Distance: is MAX ");
    
    digitalWrite(pinR, HIGH);
       
  }else if (distance  >  20 && distance <40) {
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Almost Empty");
    
    lcd.setCursor(0, 1);
    lcd.print("Distance: ");
    lcd.print(distance);
    lcd.print("cm");
    
  }else if (distance > 5 && distance <20 ) {
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Half Full");
    
    lcd.setCursor(0, 1);
    lcd.print("Distance: ");
    lcd.print(distance);
    lcd.print("cm");        
  } else if (distance <5 ) {
    
    lcd.clear();
    
    lcd.setCursor(0, 0);
    lcd.print("Full");
    
    lcd.setCursor(0, 1);
    lcd.print("Distance: ");
    lcd.print(distance);
    lcd.print("cm");    
  
  } else{

    lcd.clear();
    
    lcd.setCursor(5,0);
    lcd.print("Smart ");
    lcd.setCursor(2,1);
    lcd.print("Water bottle");
  
  }
  
  digitalWrite(pinR, LOW);
  delay(100);
  
}

// calculate the distance form the 1st  surface 
int  calDistance (){
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  long duration = pulseIn(echoPin, HIGH);
  double dist = duration * 0.034 / 2;
  int distance = (int)dist;

  return distance ;
}