#include <Wire.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,16,2);

int trig=15;
int echo=4;
int threshold=200;

void setup(){
pinMode(trig,OUTPUT);
pinMode(echo,INPUT);
Serial.begin(9600);
Wire.begin(21,22);

lcd.init();
lcd.backlight();

lcd.begin(16,2);
lcd.home();
lcd.backlight();
}

void loop(){
digitalWrite(trig,0);
delayMicroseconds(2);
digitalWrite(trig,1);
delayMicroseconds(10);
digitalWrite(trig,0);

float duration=pulseIn(echo,1);
duration=duration/2;
float distance=(0.034)*duration;
Serial.println(distance);

if(distance>threshold){
Serial.println("LESS WATER");
lcd.setCursor(0,0);
lcd.print("NOT full:");
lcd.print(distance);
}
else{
Serial.println("MORE WATER");
lcd.setCursor(0,0);
lcd.print("Full:");
lcd.print(distance);
}
delay(1000);
}