#include <Wire.h> 
#include <LiquidCrystal_I2C.h>
#include <UltraDistSensor.h>
const int TRIG_PIN   = 3; // Arduino pin connected to Ultrasonic Sensor's TRIG pin
const int ECHO_PIN   = 2; // Arduino pin connected to Ultrasonic Sensor's ECHO pin
const int BUZZER_PIN = 8; // Arduino pin connected to Piezo Buzzer's pin
const int DISTANCE_THRESHOLD = 100; // centimeters

LiquidCrystal_I2C lcd(0x27,20,4);

// variables will change:
float duration_us, distance_cm;
UltraDistSensor mysensor;
float reading;

void setup() {
  Serial.begin (9600);         // initialize serial port
  pinMode(LED_BUILTIN, OUTPUT); // set LED pin to output cuk
  pinMode(TRIG_PIN, OUTPUT);   // set arduino pin to output mode
  pinMode(ECHO_PIN, INPUT);    // set arduino pin to input mode
  pinMode(BUZZER_PIN, OUTPUT); // set arduino pin to output mode
  lcd.init();                      // initialize the lcd 
    lcd.backlight();
    Serial.begin(9600);
    mysensor.attach(3,2);//Trigger pin , Echo pin
}

float readDistanceCM() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  int duration = pulseIn(ECHO_PIN, HIGH);
  return duration * 0.034 / 2 ;
}

void loop() {
  // Float Distance
  float distance = readDistanceCM();
  // generate 10-microsecond pulse to TRIG pin
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // measure duration of pulse from ECHO pin
  duration_us = pulseIn(ECHO_PIN, HIGH);
  // calculate the distance
  distance_cm = 0.017 * duration_us;

  if(distance_cm < DISTANCE_THRESHOLD)
    digitalWrite(BUZZER_PIN, HIGH); // turn on Piezo Buzzer
  else
    digitalWrite(BUZZER_PIN, LOW);  // turn off Piezo Buzzer

  // print the value to Serial Monitor
  Serial.print("distance: ");
  Serial.print(distance_cm);
  Serial.println(" cm");

  // Led On IF distance 100 <
  bool isNearby = distance < 100;
  digitalWrite(LED_BUILTIN, isNearby);

  delay(500);

  // LCD CODING CUK
  reading=mysensor.distanceInCm();
     lcd.setCursor(0,0);
     lcd.print("Distance :- ");
      lcd.print(reading);

    delay(1000);
}