#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 20, 4);

int buzzer =2;
int led =A0;
int trig =6;
int echo =5;
long waktu,jarak;

void setup() {
lcd.init();
lcd.backlight();
lcd.clear();
lcd.setCursor(0,0);
lcd.print("water level monitor");
delay(2000);
lcd. clear();

pinMode(buzzer, OUTPUT);
pinMode(led, OUTPUT);
pinMode(trig, OUTPUT);
pinMode(echo, INPUT);
Serial.begin(9600);
}

void loop() {
  digitalWrite(trig, HIGH);
  delayMicroseconds(0);
  digitalWrite(trig, LOW);

waktu= pulseIn(echo, HIGH);
jarak= waktu/58.4;
Serial.print("ukuran =");
Serial.print(jarak);
Serial.print(" cm");
 
 lcd.setCursor(0,0);
 lcd.print("ukuran=");
 lcd.print(12,0);
 lcd.print(jarak);
 lcd.print("cm");

 if(jarak<20){
  noTone(buzzer);
  }else{
    tone(buzzer, 500, 1000);
  }

  if(jarak<20){
  digitalWrite(led, LOW);

 }else{
  digitalWrite(led, HIGH);
 }
delay(200);
}