#define BLYNK_PRINT Serial

#define BLYNK_TEMPLATE_ID "TMPL3flNEGhkD"
#define BLYNK_TEMPLATE_NAME "virtual reality navigation assistant"
#define BLYNK_AUTH_TOKEN "tNqV7WOLxdTfW5-I_t1CZaVD-IkNFgZC"

// Obstacle Detection IoT Project with ESP32, Ultrasonic Sensor, and Buzzer
#include <Arduino.h>
#include <WiFi.h>
#include <BlynkSimpleEsp32.h>

// Blynk authentication token (get it from the Blynk app)
char auth[] = "tNqV7WOLxdTfW5-I_t1CZaVD-IkNFgZC";

// Pin definitions
const int TRIG_PIN = 26;
const int ECHO_PIN = 25;
const int BUZZER_PIN = 17;
const int DISTANCE_THRESHOLD = 40;

void setup() {
  Serial.begin(9600);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(BUZZER_PIN, OUTPUT);

  // Connect to Wi-Fi
  WiFi.begin("Wokwi-GUEST","");
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }

  // Initialize Blynk
  Blynk.begin(auth, WiFi.SSID().c_str(), WiFi.psk().c_str());
}

void loop() {
  Blynk.run();

  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  unsigned long duration_us = pulseIn(ECHO_PIN, HIGH);
  float distance_cm = 0.017 * duration_us;

  if (distance_cm < DISTANCE_THRESHOLD) {
    digitalWrite(BUZZER_PIN, HIGH);
    Serial.println("Obstacle detected! Danger!");
  } else {
    digitalWrite(BUZZER_PIN, LOW);
    Serial.println("Clear path ahead.");
  }

  Serial.print("Distance: ");
  Serial.print(distance_cm);
  Serial.println(" cm");

  delay(500);
}