Uses twitter api to send a tweet from a button press on an arduino. requires arduino to have basic sketch that Serial.prints when button is pressed.

app.js

//requires the twitter and serialport node modules
// requires you capture a button press from the Arduino - see bottom for basic Arduino sketch
//NODE[save as app.js] ------------------------------------------------------------------

var Twitter = require('twitter');
 
var client = new Twitter({
  consumer_key: '',
  consumer_secret: '',
  access_token_key: '',
  access_token_secret: ''
});

// include the library

var serialport = require('serialport');
// make a local instance of it
var SerialPort = serialport.SerialPort; 
// get port name from the command line:
var portName = process.argv[2];


var myPort = new SerialPort(portName, {
    baudRate: 9600,
    // look for return and newline at the end of each data packet:
    parser: serialport.parsers.readline("\r\n")
});

myPort.on("open", handleOpen);
myPort.on("close", handleClose);
myPort.on("data", onData);

var isSending = false;

function handleOpen() {
	console.log("the connection is open ");
}

function handleClose() {
    console.log("the connection has been closed");
}

function onData(data) {
	console.log("data"+data);
	// whatever data you have 
  if(data=="ON"){
    sendTweet();
  }
}

function sendTweet(){
  client.post('statuses/update', {status: 'TWEETING ALL THE TWEETS TO TWITS AND TWEEPS'},  function(error, tweet, response){
    if(error) throw error;
    console.log(tweet);  // Tweet body. 
    console.log(response);  // Raw response object. 
  });
}

//------------------------END OF NODE
//ARDUINO SKETCH-------------------


// constants won't change. They're used here to
// set pin numbers:
const int buttonPin = 2;     // the number of the pushbutton pin
const int ledPin =  13;      // the number of the LED pin

// variables will change:
int buttonState = 0;         // variable for reading the pushbutton status
boolean hasSet = false;
void setup() {
  // initialize the LED pin as an output:
  pinMode(ledPin, OUTPUT);
  // initialize the pushbutton pin as an input:
  pinMode(buttonPin, INPUT);
  Serial.begin(9600);
}

void loop() {
  // read the state of the pushbutton value:
  buttonState = digitalRead(buttonPin);

  // check if the pushbutton is pressed.
  // if it is, the buttonState is HIGH:
  if (buttonState == HIGH) {
    // turn LED on:
    digitalWrite(ledPin, HIGH);
    if(!hasSet){
      Serial.println("ON");
      hasSet = true;
    }
    
  } else {
    // turn LED off:
    hasSet = false;
    digitalWrite(ledPin, LOW);
    
  }
}
//---------------END OF ARDUINO