int D1 = 4;
int ldr = 13; 
#include <WiFi.h>
#include <ThingSpeak.h>
char ssid[] = "Wokwi-GUEST";
char pass[] = "";
WiFiClient client;
long myChannelNumber = 2716609;
const char * myWriteAPIKey = "0I6WUX1ALT9CLB1L";
int statusCode;
#define TRIG_PIN 12
#define ECHO_PIN 14
#define RELAY_PIN 4

void setup() {
   ThingSpeak.begin(client);
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  pinMode(D1, OUTPUT);
  pinMode(ldr, INPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(RELAY_PIN, OUTPUT);

  digitalWrite(RELAY_PIN, LOW); 
}

void loop() {
      if(WiFi.status() != WL_CONNECTED)  
  {
  Serial.print("Attempting to connect");
    while(WiFi.status() != WL_CONNECTED)
    {
    WiFi.begin(ssid, pass); 
    Serial.print(".");
    delay(5000);
    }
  Serial.println("\nConnected.");
  } 
  int val = analogRead(ldr);
  long duration, distance;

  // Read distance
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  duration = pulseIn(ECHO_PIN, HIGH);
  distance = (duration / 2) / 29.1;

  // Print sensor readings
  Serial.print("LDR Value: ");
  Serial.println(val);
  Serial.print("Distance: ");
  Serial.println(distance);

  // Control logic for D1 and RELAY_PIN
  if (val >= 500 && distance < 150) {
    digitalWrite(D1, HIGH);    // Turn on D1 if both conditions are met
    digitalWrite(RELAY_PIN, HIGH); // Turn on relay if distance condition is met
  } else {
    digitalWrite(D1, LOW);    // Otherwise, turn off D1
    digitalWrite(RELAY_PIN, LOW); // Turn off relay

      ThingSpeak.setField(1,distance);
      ThingSpeak.setField(2,val);
     

  statusCode = ThingSpeak.writeFields(myChannelNumber,myWriteAPIKey);

if(statusCode == 200) { //successful writing code
Serial.println("Channel update successful.");
}
else {
Serial.println("Problem Writing data. HTTP error code :" +
String(statusCode));

  }

}
}