thingspeak arduino sketch

*/

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

// Give pin 13 a name
int led = 13;

// Local Network Settings
byte mac[] = { 0xD4, 0x28, 0xB2, 0xFF, 0xA0, 0xA1 }; // Must be unique on local network

// ThingSpeak Settings
char thingSpeakAddress[] = "api.thingspeak.com";
String thingSpeakChannel = "2738";                // Channel number looking for twitter update
String thingSpeakField = "1";                     // Field number of the CheerLights commands
const int thingSpeakInterval = 16 * 1000; // Time interval in milliseconds to get data from ThingSpeak (number of seconds * 1000 = interval)

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

// Initialize Arduino Ethernet Client
EthernetClient client;

void setup() {

  // initialize the digital pin as an output.
  pinMode(led, OUTPUT);

  // Setup Serial
  Serial.begin(9600);
  delay(100);

  Serial.flush();
  delay(100);

  // Start Ethernet on Arduino
  startEthernet();
}

void loop() {
  // if there's incoming data from the net connection.
  // send it out the serial port.  This is for debugging
  // purposes only:
  if (client.available()) {
    char c = client.read();
    Serial.print(c);
  }

  // if there's no net connection, but there was one last time
  // through the loop, then stop the client:
  if (!client.connected() && lastConnected) {
    Serial.println();
    Serial.println("disconnecting.");
    client.stop();
  }


  // store the state of the connection for next time through
  // the loop:
  lastConnected = client.connected();
}


void subscribeToThingSpeak(String tsChannel, String tsField)
{
  if (client.connect(thingSpeakAddress, 80))
  {
    Serial.println("Connecting to ThingSpeak...");
    Serial.println();

    failedCounter = 0;

    client.println("GET /channels/"+tsChannel+"/field/"+tsField+"/last.txt HTTP/1.0");
    client.println();

    lastConnectionTime = millis();
  }
  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 amd 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();
  }

  delay(1000);
}