File: src/custom/ID12RFIDReader.js

/**
 * Copyright (c) 2011-2012 Jeff Hoefs <soundanalogous@gmail.com>
 * Released under the MIT license. See LICENSE file for details.
 */

JSUTILS.namespace('BO.custom.ID12RFIDReader');

/**
 * @namespace BO.custom
 */
BO.custom.ID12RFIDReader = (function() {

  var ID12RFIDReader;

  // private static constants:
  var ID12_READER = 13,
    READ_EVENT = 1,
    REMOVE_EVENT = 2;

  // dependencies
  var EventDispatcher = JSUTILS.EventDispatcher,
    IOBoardEvent = BO.IOBoardEvent,
    RFIDEvent = BO.custom.RFIDEvent;

  /**
   * Creates an interface to an ID-12 RFID Reader. Other Innovations
   * RFID readers will likely work but have not been tested. This object
   * requires firmware other than StandardFirmata to be uploaded to the I/O board.
   * See [Breakout/custom\_examples/rfid_example1.html](https://github.com/soundanalogous/Breakout/blob/master/custom_examples/rfid_example1.html)
   * and [rfid\_example2.html](https://github.com/soundanalogous/Breakout/blob/master/custom_examples/rfid_example2.html) for
   * example applications.
   *
   * <p>To use this object with standard io objects in Breakout,
   * RFIDFirmata must be uploaded to the IOBoard rather than StandardFirmata.
   * See custom_examples/readme.txt for insturctions.</p>
   *
   * <p>Is is also possible to create a custom application for your
   * IOBoard that includes the RFID reader. See IDx_Reader_Firmata_Example
   * in the IDxRFIDReader library example files.</p>
   *
   * @class ID12RFIDReader
   * @constructor
   * @uses JSUTILS.EventDispatcher
   * @param {IOBoard} board A reference to the IOBoard instance
   * @param {Number} readerId The ID assigned to the reader in the firmware
   * running on the IOBoard (default = 13)
   */
  ID12RFIDReader = function(board, readerId) {
    "use strict";

    this.name = "ID12RFIDReader";

    this._readerId = readerId || ID12_READER;
    this._board = board;
    this._evtDispatcher = new EventDispatcher(this);

    board.addEventListener(IOBoardEvent.SYSEX_MESSAGE, this.onSysExMessage.bind(this));
  };

  ID12RFIDReader.prototype = {

    constructor: ID12RFIDReader,

    // private methods:
    /**
     * @private
     * @method onSysExMessage
     */
    onSysExMessage: function(event) {
      var message = event.message;

      if (message[0] != this._readerId) {
        return;
      } else {
        this.processRFIDData(message);
      }
    },

    // this is nice! found it here:
    // http://stackoverflow.com/questions/57803/how-to-convert-decimal-to-hex-in-javascript
    /**
     * @private
     * @method dec2hex
     */
    dec2hex: function(i) {
      return (i + 0x100).toString(16).substr(-2).toUpperCase();
    },

    /**
     * @private
     * @method processRFIDData
     */
    processRFIDData: function(data) {

      var tagEvent = this._board.getValueFromTwo7bitBytes(data[1], data[2]);
      var tagEventType = "";
      var tag = "";

      for (var i = 3, len = data.length; i < len; i += 2) {
        tag += this.dec2hex(this._board.getValueFromTwo7bitBytes(data[i], data[i + 1]));
      }

      // change this to dispatch a single event and handle add or remove in object parameter?
      if (tagEvent == READ_EVENT) {
        this.dispatch(new RFIDEvent(RFIDEvent.ADD_TAG, tag));
      } else if (tagEvent == REMOVE_EVENT) {
        this.dispatch(new RFIDEvent(RFIDEvent.REMOVE_TAG, tag));
      } else {
        // got something else
        return;
      }

    },

    /**
     * @private
     * @method dispatch
     */
    dispatch: function(event) {
      this.dispatchEvent(event);
    },

    // public methods:

    /* implement EventDispatcher */

    /**
     * @param {String} type The event type
     * @param {Function} listener The function to be called when the event is fired
     */
    addEventListener: function(type, listener) {
      this._evtDispatcher.addEventListener(type, listener);
    },

    /**
     * @param {String} type The event type
     * @param {Function} listener The function to be called when the event is fired
     */
    removeEventListener: function(type, listener) {
      this._evtDispatcher.removeEventListener(type, listener);
    },

    /**
     * @param {String} type The event type
     * return {boolean} True is listener exists for this type, false if not.
     */
    hasEventListener: function(type) {
      return this._evtDispatcher.hasEventListener(type);
    },

    /**
     * @param {Event} type The Event object
     * @param {Object} optionalParams Optional parameters to assign to the event object.
     * return {boolean} True if dispatch is successful, false if not.
     */
    dispatchEvent: function(event, optionalParams) {
      return this._evtDispatcher.dispatchEvent(event, optionalParams);
    }

  };


  // document events

  /**
   * The addTag event is dispatched when a new tag is read.
   * @type BO.custom.RFIDEvent.ADD_TAG
   * @event addTag
   * @param {BO.custom.ID12RFIDReader} target A reference to the ID12RFIDReader object.
   * @param {String} tag The RFID tag value.
   */

  /**
   * The removeTag event is dispatched when a tag is removed from the reader.
   * @type BO.custom.RFIDEvent.REMOVE_TAG
   * @event removeTag
   * @param {BO.custom.ID12RFIDReader} target A reference to the ID12RFIDReader object.
   * @param {String} tag The RFID tag value.
   */

  return ID12RFIDReader;

}());