#define BLYNK_TEMPLATE_ID "TMPL3wX6L7MxK"
#define BLYNK_TEMPLATE_NAME "Virtual iot"
#define BLYNK_AUTH_TOKEN "FnnqgdEVFGU5VxenP5TH49XMiAn7EM0C"
#define BLYNK_PRINT Serial
#include <WiFi.h>
#include <BlynkSimpleEsp32.h>

// Ultrasonic Sensor Pins
const int trigPin = 5;
const int echoPin = 18;

// Buzzer Pin
const int buzzerPin = 19;

// Blynk Auth Token
char auth[] = "FnnqgdEVFGU5VxenP5TH49XMiAn7EM0C";

// WiFi credentials for Wokwi
const char* ssid = "Wokwi-GUEST";
const char* pass = "";

// Blynk Virtual Pin
#define VIRTUAL_PIN V1

void setup() {
  // Debug console
  Serial.begin(115200);

  // Attempt to connect to WiFi
  connectToWiFi();

  // Blynk initialization
  Blynk.config(auth);
  Blynk.connect();

  // Ultrasonic Sensor Pins
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  // Buzzer Pin
  pinMode(buzzerPin, OUTPUT);
}

void loop() {
  // Reconnect WiFi if disconnected
  if (WiFi.status() != WL_CONNECTED) {
    connectToWiFi();
  }

  // Reconnect Blynk if disconnected
  if (!Blynk.connected()) {
    Blynk.connect();
  }

  // Blynk run
  Blynk.run();

  // Ultrasonic Sensor Reading
  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); // Calculating distance in cm

  // Sending distance to Blynk app
  Blynk.virtualWrite(VIRTUAL_PIN, distance+1);

  // Buzzer alert for distance less than 10 cm
  if (distance < 10) {
    digitalWrite(buzzerPin, HIGH);
  } else {
    digitalWrite(buzzerPin, LOW);
  }

  // Small delay before next measurement
  delay(500);
}

void connectToWiFi() {
  Serial.print("Connecting to WiFi...");
  WiFi.begin(ssid, pass);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.print(".");
  }
  Serial.println(" Connected to WiFi!");
}