Compass

The Compass class constructs an object that represents a single Compass or Magnetometer.

Supported Compass/Magnetometer:

• HMC6352
• HMC5883L

Parameters

• options An object of property parameters.

  Property	Type	Value/Description	Default	Required
  controller	String	"HMC6352", "HMC5883L". Defines the compass module device		yes
  gauss	Number	cgs units. Set the scale gauss for compass readings.	1.3	no

Shape

{
  heading: The current heading in degrees, 0-360°
  bearing: {
    // Example
    point: "North",
    abbr: "N",
    low: 354.38,
    mid: 360,
    high: 360
  }
}

Property Name	Description	Read Only
heading	The current heading in degrees, 0-360°	Yes
bearing	An object containing properties whose values are relevant bearing information (See below)	Yes

Property Name	Description	Read Only
point	A cardinal direction, eg. "north", "south", "east", "west"	Yes
abbr	Abbreviated point, eg. "N", "NE", "NEbE"	Yes
low	Low end of cardinal range in degrees	Yes
mid	Middle end of cardinal range in degrees	Yes
high	High end of cardinal range in degrees	Yes

Component Initialization

HMC6352

new five.Compass({
  controller: "HMC6352"
});

HMC5883L

new five.Compass({
  controller: "HMC5883L"
});

Usage

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

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

  var compass = new five.Compass({
    controller: "HMC6352"
  });

  compass.on("headingchange", function() {
    console.log("headingchange");
    console.log("  heading : ", Math.floor(this.heading));
    console.log("  bearing : ", this.bearing.name);
    console.log("--------------------------------------");
  });

  compass.on("data", function() {
    console.log("  heading : ", Math.floor(this.heading));
    console.log("  bearing : ", this.bearing.name);
    console.log("--------------------------------------");
  });
});

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

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

  var compass = new five.Compass({
    controller: "HMC5883L"
  });

  compass.on("headingchange", function() {
    console.log("headingchange");
    console.log("  heading : ", Math.floor(this.heading));
    console.log("  bearing : ", this.bearing.name);
    console.log("--------------------------------------");
  });

  compass.on("data", function() {
    console.log("  heading : ", Math.floor(this.heading));
    console.log("  bearing : ", this.bearing.name);
    console.log("--------------------------------------");
  });
});

API

There are no special API functions for this class.

Events

• change The "change" event is emitted whenever the heading of the compass has changed from it's last position
• data The "data" event is fired as frequently as the user defined freq will allow in milliseconds.

Examples