Compass

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

Supported Compass/Magnetometer:

• HMC6352
  • No longer in production, but we assume people may still have them.
• HMC5883L
  • Triple-axis Magnetometer (Compass) Board - HMC5883L
  • SparkFun Triple Axis Magnetometer Breakout - HMC5883L
• BNO055
  • Adafruit 9-DOF Absolute Orientation IMU Fusion Breakout - BNO055
• MAG3110
  • SparkFun Triple Axis Magnetometer Breakout - MAG3110
• LSM303C
  • Adafruit
  • SparkFun

This list will continue to be updated as more component support is implemented.

Parameters

• Options An object of property parameters.

  Property	Type	Value/Description	Default	Required
  controller	String	BNO055, HMC6352, HMC5883L, MAG3110, LSM303C. The name of the controller to use		yes
  gauss	Number	cgs units. Set the scale gauss for compass readings.	1.3	no

Shape

Property Name	Description	Read Only
raw	The raw x/y/z values.	Yes
heading	The current heading in degrees, 0-360°	Yes
bearing	An object of properties whose values are relevant bearing information ★	Yes

• bearing ★

  Property Name	Description	Read Only
  point	A cardinal direction, eg. "north", "south", "east", "west"	No
  abbr	Abbreviated point, eg. "N", "NE", "NEbE"	No
  low	Low end of cardinal range in degrees	No
  mid	Middle end of cardinal range in degrees	No
  high	High end of cardinal range in degrees	No

Component Initialization

BNO055

new five.Compass({
  controller: "BNO055"
});

HMC6352

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

HMC5883L

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

MAG3110

new five.Compass({
  controller: "MAG3110"
});

LSM303C

// Create an LSM303C Compass/Magnetometer object:
//
//  - attach SDA and SCL to the I2C pins on your board (A4 and A5 for the Uno)
//  - specify the LSM303C controller
new five.Compass({
  controller: "LSM303C"
});
// Or...
new five.Magnetometer({
  controller: "LSM303C"
});

Usage

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

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

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

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

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

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