#include <WiFi.h>
#include <ThingSpeak.h>
WiFiClient client;
 long myChannelNumber =  2654330;
const char * myWriteAPIKey = "A6W7YO0A6VBH5A8P";
int statusCode;
int trigger=12;
int echo=14;
float distance;
char ssid[] = "Wokwi-GUEST";
char pass[] = "";

void setup() {
ThingSpeak.begin(client);
 Serial.begin(115200);
 WiFi.mode(WIFI_STA);
pinMode(trigger, OUTPUT);
pinMode(echo, INPUT);
pinMode(26, OUTPUT);
}

int prithiv(){
digitalWrite(trigger, LOW);
delay(10);
digitalWrite(trigger, HIGH);
delay(100);
digitalWrite(trigger,LOW);
distance=pulseIn(echo, HIGH);
return(distance*0.034/2)+1;

}
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 actual_distance= prithiv();
 Serial.println(actual_distance);
  delay(10); 
 if(actual_distance>300){
  Serial.println("safe");
  tone(26, LOW);
  }
else if(actual_distance>=200 && actual_distance<=300){
  Serial.println("unsafe");
  tone(26, LOW);
}
else if(actual_distance>=0 && actual_distance<200){
  tone(26, 10000);
  Serial.println("danger");
}
else{
  tone(26, 10000);
  Serial.println("error");
}
ThingSpeak.setField(1, actual_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));
 }
}