#define BLYNK_TEMPLATE_ID "TMPL3uTQpNIR5"
#define BLYNK_TEMPLATE_NAME "smart car parking system"
#define BLYNK_AUTH_TOKEN "haL9MoN87aV1Pj_TXd0WT5cmfY1CqV3_"

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

char ssid[] = "Wokwi-GUEST";
char pass[] = "";

BlynkTimer timer;

// Define the pin connections for the ultrasonic sensor
const int trigPin = 5;
const int echoPin = 18;

// Define the LED pin
const int ledPin = 14; // Adjust the pin number as needed

long duration;
int distance;

// Function to measure the distance using the ultrasonic sensor
int getUltrasonicDistance() {
    // Clear the trigPin
    digitalWrite(trigPin, LOW);
    delayMicroseconds(2);

    // Set the trigPin HIGH for 10 microseconds
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);

    // Read the echoPin, returns the sound wave travel time in microseconds
    duration = pulseIn(echoPin, HIGH);

    // Calculate the distance
    distance = duration * 0.034 / 2; // Speed of sound wave divided by 2 (go and back)
    return distance;
}

void checkParkingStatus() {
    int distance = getUltrasonicDistance();
    Serial.print("Distance: ");
    Serial.print(distance);
    Serial.println(" cm");

    Blynk.virtualWrite(V0, distance); // Send distance to Blynk virtual pin V0
    if (distance > 100) { // Adjust the threshold as needed
        Blynk.virtualWrite(V1, "Parking space available");
        digitalWrite(ledPin, LOW); // Turn off the LED
    } else {
        Blynk.virtualWrite(V1, "Parking space occupied");
        digitalWrite(ledPin, HIGH); // Turn on the LED
    }
}

void setup() {
    Serial.begin(115200);
    Blynk.begin(BLYNK_AUTH_TOKEN, ssid, pass);

    // Initialize the ultrasonic sensor pins
    pinMode(trigPin, OUTPUT);
    pinMode(echoPin, INPUT);

    // Initialize the LED pin
    pinMode(ledPin, OUTPUT);
    digitalWrite(ledPin, LOW); // Make sure the LED is off at the start

    timer.setInterval(1000L, checkParkingStatus); // Check parking status every second
}

void loop() {
    Blynk.run();
    timer.run();
}