Learning   Examples | Foundations | Hacking | Links

Examples > Ethernet Library

Twitter Client

This example no longer works as the Twitter authentication mode has changed, and is no longer compatible with the Arduino library.

The Arduino Yún supports OAuth through Temboo. Learn more in the Temboo documentation.

This sketch connects to Twitter using an Ethernet shield. It parses the XML returned, and looks for <text>this is a tweet</text>

You can use the Arduino Ethernet shield, or the Adafruit Ethernet shield, either one will work, as long as it's got a Wiznet Ethernet module on board.

Hardware Required

  • Arduino Ethernet Shield
  • Shield-compatible Arduino board

Software Required

Circuit

The Ethernet shield allows you to connect a WizNet Ethernet controller to the Arduino via the SPI bus. It uses pins 10, 11, 12, and 13 for the SPI connection to the WizNet. Later models of the Ethernet shield also have an SD Card on board. Digital pin 4 is used to control the slave select pin on the SD card.

The shield should be connected to a network with an ethernet cable. You will need to change the network settings in the program to correspond to your network.

image developed using Fritzing. For more circuit examples, see the Fritzing project page

In the above image, your Arduino would be stacked below the Ethernet shield.

Code

/*
  Twitter Client with Strings
 
 This sketch connects to Twitter using an Ethernet shield. It parses the XML
 returned, and looks for <text>this is a tweet</text>
 
 You can use the Arduino Ethernet shield, or the Adafruit Ethernet shield,
 either one will work, as long as it's got a Wiznet Ethernet module on board.
 
 This example uses the DHCP routines in the Ethernet library which is part of the
 Arduino core from version 1.0 beta 1
 
 This example uses the String library, which is part of the Arduino core from
 version 0019.  
 
 Circuit:
 * Ethernet shield attached to pins 10, 11, 12, 13
 
 created 21 May 2011
 modified 9 Apr 2012
 by Tom Igoe
 
 This code is in the public domain.
 
 */

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


// Enter a MAC address and IP address for your controller below.
// The IP address will be dependent on your local network:
byte mac[] = {
  0x00, 0xAA, 0xBB, 0xCC, 0xDE, 0x01 };
IPAddress ip(192,168,1,20);

// initialize the library instance:
EthernetClient client;

const unsigned long requestInterval = 60000;  // delay between requests

char serverName[] = "api.twitter.com";  // twitter URL

boolean requested;                   // whether you've made a request since connecting
unsigned long lastAttemptTime = 0;            // last time you connected to the server, in milliseconds

String currentLine = "";            // string to hold the text from server
String tweet = "";                  // string to hold the tweet
boolean readingTweet = false;       // if you're currently reading the tweet

void setup() {
  // reserve space for the strings:
  currentLine.reserve(256);
  tweet.reserve(150);

 // Open serial communications and wait for port to open:
  Serial.begin(9600);
   while (!Serial) {
    ; // wait for serial port to connect. Needed for Leonardo only
  }


  // attempt a DHCP connection:
  Serial.println("Attempting to get an IP address using DHCP:");
  if (!Ethernet.begin(mac)) {
    // if DHCP fails, start with a hard-coded address:
    Serial.println("failed to get an IP address using DHCP, trying manually");
    Ethernet.begin(mac, ip);
  }
  Serial.print("My address:");
  Serial.println(Ethernet.localIP());
  // connect to Twitter:
  connectToServer();
}



void loop()
{
  if (client.connected()) {
    if (client.available()) {
      // read incoming bytes:
      char inChar = client.read();

      // add incoming byte to end of line:
      currentLine += inChar;

      // if you get a newline, clear the line:
      if (inChar == '\n') {
        currentLine = "";
      }
      // if the current line ends with <text>, it will
      // be followed by the tweet:
      if ( currentLine.endsWith("<text>")) {
        // tweet is beginning. Clear the tweet string:
        readingTweet = true;
        tweet = "";
      }
      // if you're currently reading the bytes of a tweet,
      // add them to the tweet String:
      if (readingTweet) {
        if (inChar != '<') {
          tweet += inChar;
        }
        else {
          // if you got a "<" character,
          // you've reached the end of the tweet:
          readingTweet = false;
          Serial.println(tweet);  
          // close the connection to the server:
          client.stop();
        }
      }
    }  
  }
  else if (millis() - lastAttemptTime > requestInterval) {
    // if you're not connected, and two minutes have passed since
    // your last connection, then attempt to connect again:
    connectToServer();
  }
}

void connectToServer() {
  // attempt to connect, and wait a millisecond:
  Serial.println("connecting to server...");
  if (client.connect(serverName, 80)) {
    Serial.println("making HTTP request...");
    // make HTTP GET request to twitter:
    client.println("GET /1/statuses/user_timeline.xml?screen_name=arduino&count=1 HTTP/1.1");
    client.println("HOST: api.twitter.com");
    client.println("Connection: close");
    client.println();
  }
  // note the time of this connect attempt:
  lastAttemptTime = millis();
}

See Also:

Share