TempTrack.ino

Channel ID: ******
Write APIKey:  *********************

#include <SPI.h>
#include <Ethernet.h>

int pin = 0; // analog pin
int tempc = 0,tempf=0; // temperature variables
int samples[8]; // variables to make a better precision
int maxi = -100,mini = 100; // to start max/min temperature
int i;

// Local Network Settings
byte mac[]     = { *x**, *x**, *x**, *x**, *x**, *x** }; // Must be unique on local network
byte ip[]      = { ***,***,*,*** };                // Must be unique on local network
byte gateway[] = { ***,***,*,*};
byte subnet[]  = {***, ***, ***, ***};

// ThingSpeak Settings
char thingSpeakAddress[] = “api.thingspeak.com”;
String writeAPIKey = “**************”;    // Write API Key for a ThingSpeak Channel
const int updateInterval = 10000;        // Time interval in milliseconds to update ThingSpeak

// Variable Setup
long lastConnectionTime = 0;
boolean lastConnected = false;
int failedCounter = 0;

// Initialize Arduino Ethernet Client
EthernetClient client;

void setup()
{

  Serial.begin(9600);
  Ethernet.begin(mac, ip, gateway, subnet);
  delay(1000);
  Serial.print(“ETHERNET SHIELD ip  is     : “);
  Serial.println(Ethernet.localIP());
  // Start Ethernet on Arduino
  startEthernet();
}

void loop()
{

  tempc = ( 5.0 * analogRead(pin) * 100.0) / 1024.0;

  String analogPin0 = String(tempc);

  // Print Update Response to Serial Monitor
  if (client.available())
  {
    char c = client.read();
    Serial.print(c);
  }

  // Disconnect from ThingSpeak
  if (!client.connected() && lastConnected)
  {
    Serial.println();
    Serial.println(“…disconnected.”);
    Serial.println();

    client.stop();
  }

  // Update ThingSpeak
  if(!client.connected() && (millis() – lastConnectionTime > updateInterval))
  {
    updateThingSpeak(“field1=”+analogPin0);
   }

  lastConnected = client.connected();
}

void updateThingSpeak(String tsData)
{    
  if (client.connect(thingSpeakAddress, 80))
  {
    client.print(“POST /update HTTP/1.1\n”);
    client.print(“Host: api.thingspeak.com\n”);
    client.print(“Connection: close\n”);
    client.print(“X-THINGSPEAKAPIKEY: “+writeAPIKey+”\n”);
    client.print(“Content-Type: application/x-www-form-urlencoded\n”);
    client.print(“Content-Length: “);
    client.print(tsData.length());
    client.print(“\n\n”);

    client.print(tsData);

    lastConnectionTime = millis();

    if (client.connected())
    {
      Serial.println(“Connecting to ThingSpeak…”);
      Serial.println();

      failedCounter = 0;
     }
     
     else
     {
      failedCounter++;

      Serial.println(“Connection to ThingSpeak failed (“+String(failedCounter, DEC)+”)”);
      Serial.println();
     }
  }
  
  else
  {
    failedCounter++;

    Serial.println(“Connection to ThingSpeak Failed (“+String(failedCounter, DEC)+”)”);
    Serial.println();

    lastConnectionTime = millis();
   }
}

void startEthernet()
{

  client.stop();

  Serial.println(“Connecting Arduino to network…”);
  Serial.println();

  delay(1000);

  // Connect to network and obtain an IP address using DHCP
  if (Ethernet.begin(mac) == 0)
  {
    Serial.println(“DHCP Failed, reset Arduino to try again”);
    Serial.println();
  }
  
  else 
  {
    Serial.println(“Arduino connected to network using DHCP”);
    Serial.println();
    Serial.println(“Data being uploaded to THINGSPEAK Server…….”);
    Serial.println();
  }

  delay(1000);
}