johnny-five/lib/switch.js

var Board = require("./board");
var Collection = require("./mixins/collection");
var Emitter = require("events").EventEmitter;
var Fn = require("./fn");
var util = require("util");

var aliases = {
  close: ["close", "closed", "on"],
  open: ["open", "off"]
};


/**
 * Switch
 * @constructor
 *
 * five.Switch();
 *
 * five.Switch({
 *   pin: 10
 * });
 *
 *
 * @param {Object} opts [description]
 *
 */

function Switch(opts) {

  if (!(this instanceof Switch)) {
    return new Switch(opts);
  }

  // Create a 5 ms debounce boundary on event triggers
  // this avoids button events firing on
  // press noise and false positives
  var trigger = Fn.debounce(function(key) {
    aliases[key].forEach(function(type) {
      this.emit(type, null);
    }, this);
  }, 5);

  Board.Component.call(
    this, opts = Board.Options(opts)
  );
  
  // Resolve the default type to Normally Open
  opts.type = opts.type || "NO";

  // Is this instance Normally Open?
  var isNormallyOpen = opts.type === "NO";
  var raw = null;
  var invert = typeof opts.invert !== "undefined" ?
    opts.invert : (isNormallyOpen || false);

  // Logical Defaults
  var closeValue = 1;
  var openValue = 0;

  if (invert) {
    closeValue ^= 1;
    openValue ^= 1;
  }

  this.io.pinMode(this.pin, this.io.MODES.INPUT);

  if (isNormallyOpen) {
    this.io.digitalWrite(this.pin, this.io.HIGH);
  }

  this.io.digitalRead(this.pin, function(data) {
    raw = data;

    trigger.call(this, this.isOpen ? "open" : "close");
  }.bind(this));

  Object.defineProperties(this, {
    value: {
      get: function() {
        return Number(this.isOpen);
      }
    },
    invert: {
      get: function() {
        return invert;
      },
      set: function(value) {
        invert = value;
        closeValue = invert ? 0 : 1;
        openValue = invert ? 1 : 0;
      }
    },
    closeValue: {
      get: function() {
        return closeValue;
      },
      set: function(value) {
        closeValue = value;
        openValue = value ^ 1;
      }
    },
    openValue: {
      get: function() {
        return openValue;
      },
      set: function(value) {
        openValue = value;
        closeValue = value ^ 1;
      }
    },
    isOpen: {
      get: function() {
        return raw === openValue;
      }
    },
    isClosed: {
      get: function() {
        return raw === closeValue;
      }
    },
  });
}

util.inherits(Switch, Emitter);


/**
 * Fired when the Switch is close
 *
 * @event
 * @name close
 * @memberOf Switch
 */


/**
 * Fired when the Switch is opened
 *
 * @event
 * @name open
 * @memberOf Switch
 */


/**
 * Switches()
 * new Switches()
 *
 * Constructs an Array-like instance of all servos
 */

function Switches(numsOrObjects) {
  if (!(this instanceof Switches)) {
    return new Switches(numsOrObjects);
  }

  Object.defineProperty(this, "type", {
    value: Switch
  });

  Collection.Emitter.call(this, numsOrObjects);
}

util.inherits(Switches, Collection.Emitter);

Collection.installMethodForwarding(
  Switches.prototype, Switch.prototype
);

// Assign Switches Collection class as static "method" of Switch.
Switch.Collection = Switches;



module.exports = Switch;