#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

const int trigger = 32;
const int echo = 33;
const int pump = 25;
const int buzzer = 26;

bool buzzFlag = false;
float levellow = 20.0;
float levelhigh = 40.0;
long duration;
float distance;
int waterlevel; 
void setup(){
    lcd.init();
    lcd.backlight();
    pinMode(trigger, OUTPUT);
    pinMode(echo, INPUT);
    pinMode(pump, OUTPUT);
    pinMode(buzzer, OUTPUT); 
}

void loop(){
    digitalWrite(trigger, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigger, LOW);
    
    duration = pulseIn(echo, HIGH);
    distance = (duration/2)/29.1;
    
    waterlevel = ((distance - levellow)/(levelhigh - levellow))*100;
    if(waterlevel <0){
        waterlevel = 0;
    }
    if(waterlevel >100){
        waterlevel = 100;
    }
    
    lcd.setCursor(0,0);
    lcd.print("WATERLEVEL=");
    lcd.setCursor(11,0);
    lcd.print(waterlevel);
    lcd.print("%  ");
    
  if(waterlevel <= 10){
    digitalWrite(pump, HIGH);
        if(!buzzFlag){
        digitalWrite(buzzer, HIGH);
        delay(1000);
        digitalWrite(buzzer, LOW);
        buzzFlag = true;
    }
    lcd.setCursor(0,1);
    lcd.print("WATERPUMP=ON ");
    
}
    else if(waterlevel >= 90){
    digitalWrite(pump, LOW);
    lcd.setCursor(0,1);
    lcd.print("WATERPUMP=OFF");
    
}
}