#include <WiFi.h>
#include <WiFiClient.h>
#include <BlynkSimpleEsp32.h>

// Replace with your own WiFi credentials
char ssid[] = "YourWiFiSSID";
char pass[] = "YourWiFiPassword";

// Replace with your own Blynk authentication token
char auth[] = "YourBlynkAuthToken";

// Pins for ultrasonic sensor
const int trigPin = 2;   // Trigger pin of HC-SR04
const int echoPin = 4;   // Echo pin of HC-SR04

// Pins for LEDs
const int led1 = 5;
const int led2 = 6;
const int led3 = 7;
const int led4 = 8;

void setup() {
  Serial.begin(115200);

  Blynk.begin(auth, ssid, pass);
  
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
  pinMode(led4, OUTPUT);
  
  // Turn off all LEDs initially
  digitalWrite(led1, LOW);
  digitalWrite(led2, LOW);
  digitalWrite(led3, LOW);
  digitalWrite(led4, LOW);
}

void loop() {
  Blynk.run();
  
  long duration, distance;
  
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;
  
  // LED control based on distance
  if (distance >= 2 && distance <= 200) {
    digitalWrite(led1, HIGH);
    digitalWrite(led2, HIGH);
    digitalWrite(led3, LOW);
    digitalWrite(led4, LOW);
  } else if (distance >= 201 && distance <= 399) {
    digitalWrite(led1, HIGH);
    digitalWrite(led2, LOW);
    digitalWrite(led3, HIGH);
    digitalWrite(led4, LOW);
  } else if (distance == 400) {
    digitalWrite(led1, LOW);
    digitalWrite(led2, LOW);
    digitalWrite(led3, LOW);
    digitalWrite(led4, HIGH);
  } else {
    digitalWrite(led1, LOW);
    digitalWrite(led2, LOW);
    digitalWrite(led3, LOW);
    digitalWrite(led4, LOW);
  }
  
  delay(1000);  // Adjust this delay as needed
}