#include <Arduino.h>
#include <WiFi.h>
#include <ThingSpeak.h>
char ssid[] ="Wokwi-GUEST";
char pass[] ="";
WiFiClient client;
unsigned long mychannelnumber =2647629;
const char *myWriteAPIKey = "6E5A703VQLO71FL5";
int statuscode;

#define TRIG_PIN 5
#define ECHO_PIN 18
#define RELAY_PIN 15

void setup() {
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(RELAY_PIN, OUTPUT);

  digitalWrite(RELAY_PIN, LOW); 
  Serial.begin(115200);


WiFi.mode(WIFI_STA);
 ThingSpeak.begin(client);

}

void loop() {
  long duration, 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;

  Serial.print("Distance: ");
  Serial.println(distance);


  if (distance > 200) {
    digitalWrite(RELAY_PIN, HIGH); 
  } else {
    digitalWrite(RELAY_PIN, LOW); 
  }
 
  delay(100); 






  (WiFi.status() != WL_CONNECTED);
  {
    Serial.println("Attempting to connect");
    while(WiFi.status()!= WL_CONNECTED)
    {
        WiFi.begin(ssid,pass);
        delay(5000);
    }
Serial.println("\nConnected.");
  }
  ThingSpeak.setField(1,distance);
 statuscode=ThingSpeak.writeFields(mychannelnumber,myWriteAPIKey);
 if(statuscode==200){
  Serial.println("Channel update successful.");
  }
  else 
  {
    Serial.println("Problem Writing data. HTTP error code :" + String(statuscode));
  }
    delay(15000);
  }