#include <LiquidCrystal_I2C.h>
#include "pitches.h"

#define BUZZER_PIN 10
LiquidCrystal_I2C lcd(0x27, 16, 2);

int trig_pin = 2;
int echo_pin = 3;
long echotime;
float distance;

int melody[] = {
  NOTE_E5, NOTE_D5, NOTE_FS4, NOTE_GS4, 
  NOTE_CS5, NOTE_B4, NOTE_D4, NOTE_E4, 
  NOTE_B4, NOTE_A4, NOTE_CS4, NOTE_E4,
  NOTE_A4
};

int durations[] = {
  8, 8, 4, 4,
  8, 8, 4, 4,
  8, 8, 4, 4,
  2
};

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(trig_pin, OUTPUT);
  pinMode(echo_pin, INPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  //pinMode(8, OUTPUT);
  
  digitalWrite(trig_pin, LOW);
  lcd.begin(16, 2);
  lcd.setCursor(0,0);
  lcd.print("DIST DTECTR v0.1");
  lcd.setCursor(0,1);
  lcd.print("LOADING...");
  delay(2300);
}

void loop() {
    loop1();
}
void loop1() {
  lcd.clear();
  digitalWrite(trig_pin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig_pin, LOW);
  echotime= pulseIn(echo_pin, HIGH);
  distance= 0.0001*((float)echotime*340.0)/2.0;
  lcd.setCursor(0,0);
  lcd.println("Distance :");
  lcd.setCursor(0,1);
  lcd.print(distance);
  lcd.print(" cm");
  if(distance < 30)
  {
    loop2();
    //digitalWrite(8, HIGH);
  }
  else
  {
    //digitalWrite(8, LOW);
  }
  delay(100);
}

void loop2() {
  int size = sizeof(durations) / sizeof(int);

  for (int note = 0; note < size; note++) {
    //to calculate the note duration, take one second divided by the note type.
    //e.g. quarter note = 1000 / 4, eighth note = 1000/8, etc.
    int duration = 1000 / durations[note];
    tone(BUZZER_PIN, melody[note], duration);

    //to distinguish the notes, set a minimum time between them.
    //the note's duration + 30% seems to work well:
    int pauseBetweenNotes = duration * 1.30;
    delay(pauseBetweenNotes);
    
    //stop the tone playing:
    noTone(BUZZER_PIN);
  }
}