LED Ring

Homey's LED ring consists of 24 RGB LED's that apps can control and supply new animations for.

The LED Ring can only be controlled on Homey Pro (Early 2019) and older models. Add platformLocalRequiredFeatures to the App Manifest to make sure the app can not be installed on Homey Pros that do not have a controllable LED Ring.

Your app may control Homey's LED Ring to give visual feedback when your app is doing something. It is also possible to take control of the LED Ring when Homey is idling, this is called a screensaver.

In order to access the LED Ring your app will need the homey:manager:ledring permission. For more information about permissions read the Permissions guide.

Playing a LED Ring animation

To keep the user interaction of Homey consistent, you can play a system-provided animation.

/app.js

const Homey = require('homey');

class App extends Homey.App {
  async onInit() {
    const pulseAnimation = await this.homey.ledring.createSystemAnimation("pulse");
    await pulseAnimation.start();
  }
}

module.exports = App;

Creating your own LED Ring animation

An animation is essentially a JavaScript object with frames and settings about the frame speed and rotation speed.

/app.js

const Homey = require('homey');

class App extends Homey.App {
  async onInit() {
    const myAnimation = await this.homey.ledring.createAnimation({
      options: {
        fps: 1, // real frames per second
        tfps: 60, // target frames per second. this means that every frame will be interpolated 60 times
        rpm: 0, // rotations per minute
      },
      frames: [],
      priority: "INFORMATIVE", // or FEEDBACK, or CRITICAL
      duration: 3000, // duration in ms, or keep empty for infinite
    });

    // register the animation with Homey
    myAnimation
      .on("start", () => {
        // The animation has started playing
      })
      .on("stop", () => {
        // The animation has stopped playing
      });

    await myAnimation.start();
  }
}

module.exports = App;

The animation object is an Array, which contains frames. A frame is an Array with 24 Object values, that represent the color of that pixel. The pixel object is contains the properties r, g and b, respectively red, green and blue on a scale of 0 - 255.

For example, to create a spinning red dot:

const frames = [];
const frame = [];

// for every pixel...
for (let pixelIndex = 0; pixelIndex < 24; pixelIndex++) {
  let colors = {
    r: 0,
    g: 0,
    b: 0,
  };

  // set the first pixel to red
  if (pixelIndex === 0) {
    colors.r = 255;
  }

  frame.push(colors);
}

// and finally, add the generated frame to the frames array
frames.push(frame);

Screensaver

Your app can register a screensaver, which can be chosen by going to Settings → LED Ring, and executed when Homey is idling.

Define your screensaver(s) in your App Manifest as follows:

/.homeycompose/screensavers/weather.json

{
  "title": {
    "en": "Weather",
    "nl": "Weer"
  }
}

And from within your app, register your animation instance as follows:

/app.js

const Homey = require('homey');

class App extends Homey.App {
  async onInit() {
    const myAnimation = await this.homey.ledring.createAnimation({
      // ...
    });

    // If this animation is also a screensaver, we must register it first.
    // 'weather' is the screensaver name defined in our app.json
    myAnimation.registerScreensaver("weather")
      .then(this.log)
      .catch(this.error);
  }
}

module.exports = App;

For live animations, simply update your animation using LedringAnimation#updateFrames() when needed.