rwldrn/johnny-five — pull request #161 by bobholt (2013-07-09 23:22:05+00:00)
Title: add isPullup option

Adding option to enable pullup resistor on button. Automatically sets `invert` to true unless it was explicitly set to false in the options hash.

Script and schematic if you want to check it out:

```js
var five = require( 'johnny-five' );

five.Board().on( 'ready', function() {

var buttonPin = 2;
var ledPin = 13;

var button = new five.Button({
pin: buttonPin,
isPullup: true
});

var led = new five.Led({
pin: ledPin
});

button.on('down', function(value){
led.on();
});

button.on('up', function(){
led.off();
});

});
```

Setting `isPullup` to false or adding the `invert: false` option changes the behavior on the board as expected.

![inputpullupbutton](https://f.cloud.github.com/assets/94167/771817/fa096194-e8ed-11e2-87cb-003283df8fad.png)