#include <WiFi.h>
#include <ThingSpeak.h>

//define sound speed in cm/uS
#define SOUND_SPEED 0.034
#define CM_TO_INCH 0.393701

// Name of the router and password
const char* ssid = "Wokwi-GUEST";
const char* password = "";

const int trigPin = 19;
const int echoPin = 18;

long duration;
float distanceCm;
float distanceInch;

//ThingSpeak Setting
unsigned long channelNumber = 2592067; //channel Id
const char* writeAPIKey = "NPBKZIT27XBSO66G"; //API key

WiFiClient client;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);

  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
  pinMode(echoPin, INPUT); 

  // Start wifi - 2 parameters (ssid & password)
  WiFi.begin(ssid, password);
  Serial.println("Connecting to WiFi");

  // Connection status
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  // Connection Info
  Serial.println("");
  Serial.println("WiFi connected!");
  Serial.print("IP Address: ");
  Serial.println(WiFi.localIP());

  ThingSpeak.begin(client);
}

void loop() {
  // Clears the trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  // Sets the trigPin on HIGH state for 10 micro seconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);
  
  // Calculate the distance
  distanceCm = duration * SOUND_SPEED/2;
  
  // Convert to inches
  distanceInch = distanceCm * CM_TO_INCH;
  
  // Prints the distance in the Serial Monitor
  Serial.print("Distance (cm): ");
  Serial.println(distanceCm);

  //set the field
  // 2 parameter - 1.field, 2.name of the field
  ThingSpeak.setField(1, distanceCm);

  //Write to ThingSpeak
  //// 2 parameter - 1.channel num, 2.WAPIKEY
  int x = ThingSpeak.writeFields(channelNumber, writeAPIKey);
  

  //check wheather running or not
  if(x == 200) { 
    Serial.println("Success!");
  } else {
    Serial.println("Faild: "+ String(x));
  }

  delay(1000);
}