#include <ESP32Servo.h>

Servo myservo;  // create servo object to control a servo

// Define pin numbers
const int trigPin = 5;
const int echoPin = 4;
const int buzzerPin = 19;
const int led1 = 21;
const int led2 = 22;
const int led3 = 23;
long duration;
int distance;

void setup() {
  myservo.attach(18);  // attaches the servo on pin 18 to the servo object
  pinMode(trigPin, OUTPUT); // Sets the trigPin as an OUTPUT
  pinMode(echoPin, INPUT);  // Sets the echoPin as an INPUT
  pinMode(led1, OUTPUT);  // LED pin as OUTPUT
  pinMode(led2, OUTPUT);  // LED pin as OUTPUT
  pinMode(led3, OUTPUT);  // LED pin as OUTPUT
  pinMode(buzzerPin, OUTPUT); // Buzzer pin as OUTPUT
  Serial.begin(9600);       // Initialize serial communication
}

void loop() {
  // Clear the trigPin by setting it LOW for a moment
  digitalWrite(trigPin, LOW);  
  delayMicroseconds(2); 
  
  // Trigger the sensor by setting trigPin HIGH for 10 microseconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10); 
  digitalWrite(trigPin, LOW);
  
  // Read the echoPin and calculate the distance
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2; // Calculate the distance
  
  // LED and buzzer control based on distance
  if (distance > 300) {
    digitalWrite(led1, HIGH);
    digitalWrite(led2, LOW);
    digitalWrite(led3, LOW);
    digitalWrite(buzzerPin, LOW);
    myservo.write(0); // Servo at 0 degrees
  } 
  else if (distance > 250) {
    digitalWrite(led1, HIGH);
    digitalWrite(led2, HIGH);
    digitalWrite(led3, LOW);
    digitalWrite(buzzerPin, LOW);
    myservo.write(0); // Servo at 0 degrees
  } 
  else if (distance < 200) {
    digitalWrite(led1, HIGH);
    digitalWrite(led2, HIGH);
    digitalWrite(led3, HIGH);
    digitalWrite(buzzerPin, HIGH); // Activate buzzer
    myservo.write(180); // Rotate servo to 180 degrees
  } 
  else { // Distance between 200 and 250 cm
    digitalWrite(led1, HIGH);
    digitalWrite(led2, LOW);
    digitalWrite(led3, LOW);
    digitalWrite(buzzerPin, LOW);
    myservo.write(0); // Servo at 0 degrees
  }
  
  delay(100); // Delay to improve simulation
}