#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <Ultrasonic.h>

const int trig = 11;
const int echo = 12;

const int LED1 = 2;
const int LED2 = 3;
const int LED3 = 4;
const int buzzer = 5;

const int sda = 8;
const int scl = 9;

int duration = 0;
int distance = 0;

LiquidCrystal_I2C lcd(0x27, 16, 2);

Ultrasonic ultrasonic(trig, echo);

void setup() {
pinMode(trig, OUTPUT);
pinMode(echo, INPUT);
pinMode(LED1, OUTPUT);
pinMode(LED2, OUTPUT);
pinMode(LED3, OUTPUT);
pinMode(buzzer, OUTPUT);
Serial.begin(9600);

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

void loop() {
digitalWrite(trig, HIGH);
delayMicroseconds(1000);
digitalWrite(trig, LOW);

duration = pulseIn(echo, HIGH);
distance = (duration / 2) / 28.5;
Serial.println(distance);

lcd.setCursor(0, 0);
lcd.print("Distance: ");
lcd.print(distance);
lcd.print(" cm");

if (distance <= 50) {
blinkLED(LED1, 100);
playTone(buzzer, 2000, 100);
} else if (distance > 50 && distance <= 100) {
blinkLED(LED2, 500);
playTone(buzzer, 1500, 500);
} else if (distance > 100 && distance <= 200) {
blinkLED(LED3, 1000);
playTone(buzzer, 1000, 1000);
} else {
digitalWrite(LED1, LOW);
digitalWrite(LED2, LOW);
digitalWrite(LED3, LOW);
noTone(buzzer);
}
}

void blinkLED(int pin, int delayTime) {
digitalWrite(pin, HIGH);
delay(delayTime);
digitalWrite(pin, LOW);
delay(delayTime);
}

void playTone(int pin, int frequency, int duration) {
tone(pin, frequency);
delay(duration);
noTone(pin);
}