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

char ssid[] = "Wokwi-GUEST"; 
char pass[] = ""; 
WiFiClient client;
unsigned long myChannelNumber = 2246621;
const char * myWriteAPIKey = "MHL3L4SC8J098ZSU";

int sensorPin = 34;   // select the input pin for the LM35 sensor
int digitalValue;  // variable to store the value coming from the sensor
float analogVoltage;
float temp;
int statusCode;

void setup() { 
  Serial.begin(115200); 
  ThingSpeak.begin(client);
  WiFi.mode(WIFI_STA);  
  pinMode(sensorPin, INPUT); 
}

void loop() { 
  connectToCloud(); 
  computeData(); 
  writeData(); 
  delay(1000);
}

void connectToCloud(){ 
  if(WiFi.status() != WL_CONNECTED) 
  {
Serial.print("Attempting to connect"); 
while(WiFi.status() != WL_CONNECTED) 
{
WiFi.begin(ssid, pass); 
for(int i=0;i<5;i++) 
{ 
  Serial.print(".");
delay(1000);
}
 
}
Serial.println("\nConnected.");
}
}

void computeData(){
// Get the analog value from lm35 sensor and convert that value into digital value using ADC converter
  digitalValue = analogRead(sensorPin);
  Serial.print("digital value = ");
  Serial.print(digitalValue);        //print digital value on serial monitor
  //convert digital value to analog voltage
  //Analog voltage = digital value * (Vref/2^n – 1)
  //Here Vref is 5V that we connected to lm35 sensor.If we connect 3.3V to sensor then Vref is 3.3V
  //Here we use 10 bit ADC so n=10 bits so the values ranges from 0 to 1023
  analogVoltage = (digitalValue * 3.3)/4095.00;
  Serial.print("  analog voltage = ");
  Serial.println(analogVoltage);
  //To convert analog voltage to temperature in Celcius, we multiply by 100 
  //because the LM35 output is 0.010V per degree. ie 1 degree =0.010V or 1V=100 degree
  temp=analogVoltage * 100;
  Serial.print("temperature = ");
  Serial.println(temp);
  delay(1000);
}

void writeData(){ 
  ThingSpeak.setField(1, temp);
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));
delay(15000); // data to be uploaded every 15secs
}