#define BLYNK_TEMPLATE_ID "TMPL3Rxeg_6JB"
#define BLYNK_TEMPLATE_NAME "new project"
#define BLYNK_AUTH_TOKEN "z_bfrIoT1QBaZ6k1pYESe4YHbcpALvG2"
#include <Adafruit_Sensor.h>
#include <DHT.h>
#include <DHT_U.h>
#include <WiFi.h>
#include <BlynkSimpleEsp32.h>

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

// WiFi credentials
char ssid[] = "wokwi-GUEST";
char pass[] = "";

// Define pins
#define TRIG_PIN 18
#define ECHO_PIN 19
#define DHT_PIN 21
#define BUTTON_PIN 22
#define LED_PIN 25
#define BUZZER_PIN 26

// DHT setup
#define DHTTYPE DHT22
DHT dht(DHT_PIN, DHTTYPE);

// Variables for distance measurement
long duration;
float distance;

// Variables for temperature measurement
float temperature;

// Blynk virtual pins
#define VIRTUAL_PIN_TEMP V1
#define VIRTUAL_PIN_DIST V2
#define VIRTUAL_PIN_BRAKE V3
#define VIRTUAL_PIN_LED V4

void setup() {
  // Initialize serial communication
  Serial.begin(115200);

  // Initialize pins
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(BUTTON_PIN, INPUT_PULLUP);
  pinMode(LED_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  
  // Initialize DHT sensor
  dht.begin();

  // Connect to WiFi and Blynk
  Blynk.begin(auth, ssid, pass);
}

void loop() {
  // Blynk run
  Blynk.run();

  // Collision detection
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  duration = pulseIn(ECHO_PIN, HIGH);
  distance = duration * 0.034 / 2;
  
  // Temperature measurement
  temperature = dht.readTemperature();
  
  // Brake status
  bool brakePressed = digitalRead(BUTTON_PIN) == LOW;
  
  // Send data to Blynk
  Blynk.virtualWrite(VIRTUAL_PIN_TEMP, temperature);
  Blynk.virtualWrite(VIRTUAL_PIN_DIST, distance);
  Blynk.virtualWrite(VIRTUAL_PIN_BRAKE, brakePressed);

  // Check safety conditions
  if (distance < 20) {
    digitalWrite(LED_PIN, HIGH);    // Turn on LED
    digitalWrite(BUZZER_PIN, HIGH); // Turn on Buzzer (Optional)
    Blynk.virtualWrite(VIRTUAL_PIN_LED, 255); // Update virtual LED status in Blynk app
  } else {
    digitalWrite(LED_PIN, LOW);     // Turn off LED
    digitalWrite(BUZZER_PIN, LOW);  // Turn off Buzzer 
    Blynk.virtualWrite(VIRTUAL_PIN_LED, 0);   // Update virtual LED status in Blynk app
  }

  delay(1000); // Adjust as needed
}