JavaScript Robotics: Button API (Johnny-Five)

Parameters
Shape
Component Initialization
Usage
API
Events

The Button class constructs objects that represents a single Button attached to the physical board.

Parameters

pin A Number or String address for the Button pin (digital).

var button = new five.Button(8);

// Attached to an analog pin
var button = new five.Button("A0");

Options An object of property parameters.

Property	Type	Value/Description	Default	Required
pin	Number, String	Digital Pin. The Number or String address of the pin the button is attached to, ie. 5 or “I1”		yes
invert	Boolean	`true`, `false`. Invert the up and down values. This is useful for inverting button signals when the pin itself doesn’t have built-in pullup resistor capabilities.	`false`	no
isPullup	Boolean	`true`, `false`. Initialize as a pullup button	`false`	no
isPulldown	Boolean	`true`, `false`. Initialize as a pulldown button	`false`	no
holdtime	Number	Time in milliseconds that the button must be held until emitting a "hold" event.	500ms	no
debounce	Number	Time in milliseconds to delay button events. Cleans up "noisy" state changes.	7ms	no

Shape

Property Name	Description	Read Only
`id`	A user definable id value. Defaults to a generated uid	No
`pin`	The pin address that the Button is attached to	No
`downValue`	0 or 1, depending on invert or pullup	No
`upValue`	0 or 1, depending on invert or pullup	No
`holdtime`	milliseconds	No

Component Initialization

Basic

new five.Button(2);

Inverted

new five.Button({
  pin: 2,
  invert: true
});

Usage

var five = require("johnny-five");
var board = new five.Board();

board.on("ready", function() {

  // Create a new `button` hardware instance.
  var button = new five.Button(2);

  button.on("hold", function() {
    console.log( "Button held" );
  });

  button.on("press", function() {
    console.log( "Button pressed" );
  });

  button.on("release", function() {
    console.log( "Button released" );
  });
});

Events

hold The button has been held for holdtime milliseconds
down, press The button has been pressed.
up, release The button has been released.

Collection

Button supports a Buttons collection class, which allows multiple Button instances to be controlled via a single instance object. Events emitted by instances of the Button class are forwarded through instances of the Buttons class. The handler receives the instance that emitted the event as the first parameter.

new five.Buttons([ 2, 3, 4, 5 ]);
new five.Buttons([ { pin: 2 }, { pin: 3 }, { pin: 4 }, { pin: 5 } ]);
new five.Buttons([ button1, button2, button3 ]);