use Tessel to control Sony TV

ir.js

var tessel = require('tessel');
var sony = require('./sony');
var infraredlib = require('ir-attx4');
var infrared = infraredlib.use(tessel.port['A']); 

// When we're connected
infrared.on('ready', function() {
  if (!err) {
    console.log("Connected to IR!");
    // Start sending a signal every three seconds
    var timer = setInterval(function() {
      // Make a buffer of on/off durations (each duration is 16 bits)
       var powerBuffer = sony.generateIRCodeForSending(0xA90);
      // Sony signal at 40 kHz
      // https://github.com/shirriff/Arduino-IRremote/blob/master/IRremote.cpp  @line 96
      infrared.sendRawSignal(40, powerBuffer, function(err) {
        if (err) {
          console.log("Unable to send signal: ", err);
        } else {
          console.log("Signal sent!");
        }
      });
    }, 3000); // Every 3 seconds
  } else {
    console.log(err);
  }
});

// If we get data, print it out
infrared.on('data', function(data) {
    console.log("Received RX Data: ", data);
});

sony.js

// because this bug, you must write a negative number to buffer as it's complement using writeUIntXX
// https://forums.tessel.io/t/write-negative-number-to-buffer-got-zero/642
var get16BitsComplement = function (number) {
  return number < 0 ? (65536 + number) : number;
};

// Tessel IR module lib using duration factor 50
var factor = 50;
var headerBytes = [2400 / factor, get16BitsComplement(-600 / factor)];
var oneOnDuration = 1200 / factor;
var zeroOnDuration = 600 / factor;
var offDuration = get16BitsComplement(-600 / factor);
var repeatDuration = get16BitsComplement(-25700 / factor);
var bodyLen = 12;

function generateIRCode(hexValue) {
  var headerBuf = new Buffer(4);
  headerBuf.writeUInt16BE(headerBytes[0], 0);
  headerBuf.writeUInt16BE(headerBytes[1], 2);

  // multiply by 4 b/c we're sending int16s (2 8-byte words) for each duration
  // and there is both an on and an off duration
  var bodyBuf = new Buffer(bodyLen * 2 * 2);

  for (var i = 0; i < bodyLen; i++) {
    // If the next bit is a 1
    if ((hexValue >> (bodyLen - i - 1)) & 1) {
      // Write the one ON duration
      bodyBuf.writeUInt16BE(oneOnDuration, i * 4);
    } else {
      // Write the zero ON duration
      bodyBuf.writeUInt16BE(zeroOnDuration, i * 4);
    }

    // Write the standard OFF duration
    bodyBuf.writeUInt16BE(offDuration, (i * 4) + 2);

  }
  bodyBuf.writeUInt16BE(repeatDuration, bodyBuf.length - 2);
  return Buffer.concat([headerBuf, bodyBuf]);
};

var generateIRCodeForSending = exports.generateIRCodeForSending = function (hexValue) {
  return Buffer.concat([generateIRCode(hexValue), generateIRCode(hexValue), generateIRCode(hexValue)]);
};

because tessel ir lib will update to hidden factor, when using whith new lib change factor to number 1