# Unicorn pHat with NodeJS

**URL:** <https://forums.pimoroni.com/t/unicorn-phat-with-nodejs/3113>\
**Category:** Projects\
**Created:** [September 30, 2016, 3:19pm UTC](https://forums.pimoroni.com/t/unicorn-phat-with-nodejs/3113 "2016-09-30T15:19:46Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![jason](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.pimoroni.com/jason/32/1645_2.png) [@jason](https://forums.pimoroni.com/u/jason)\
**Post date:** [September 30, 2016, 3:19pm UTC](https://forums.pimoroni.com/t/unicorn-phat-with-nodejs/3113/1 "2016-09-30T15:19:46Z")

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Hello!

I have a confession: I’m not a Python person. So, as soon as I received my Unicorn pHat I searched for a way to program it using NodeJS.  
I found a really nice Node module wrapping the C library `rpi_ws281x`. It is called `node-rpi-ws281x-native` and it is available through npm or Github.

Here is a tiny example to get you up and running:

- First you need NodeJS. On the downloads page [here](https://nodejs.org/en/download/) select the ARM v6 tarball. I usually select the link in my browser and then use wget in an ssh terminal.
- Then you can install it by following [this tutorial](http://www.thegeekstuff.com/2015/10/install-nodejs-npm-linux).
- Create a folder for your project somewhere. I created a `node-unicorn` folder on my home directory: `mkdir node-unicorn`
- In that directory create a new NodeJS project with the command `npm init`. Press `enter` for all the questions and this will create a `package.json` for you.
- Install the main module with the command: `npm install node-rpi-ws281x-native --save`
- Create a file called `index.js` with the following code inside:

```auto
var NUMBER_OF_LEDS = 32; // 32 leds in the Unicorn pHat

var strip = require('rpi-ws281x-native');
strip.init(NUMBER_OF_LEDS);
strip.setBrightness(50); // A value between 0 and 255

// The RGB colours of the LEDs. for instance 0xff0000 is red, 0x0000ff is blue, etc.
var leds = [
    0,0,0,0,0,0,0,0,
    0,0,0,0,0,0,0,0,
    0,0,0,0,0,0,0,0,
    0,0,0,0,0,0,0,0    
];

// Loop every 0.1 sec: randomise an index and a colour and display it
strip.render(leds);
var interval = setInterval(function() {
    var randomIndex = Math.floor(Math.random() * NUMBER_OF_LEDS);
    var randomColour = Math.floor(Math.random() * 0xffffff);
    leds[randomIndex] = randomColour;
    console.log('Rendering colour ' + randomColour + ' at index ' + randomIndex);
    strip.render(leds);
}, 100);

// After 10 secondes, stop.
setTimeout(function () {
    console.log('Stop!');
    clearInterval(interval);
    strip.reset();
}, 10000);

```

- Exactly as the Python library, you need to execute this code as root using: `sudo node index.js`
- For 10 seconds, every tenth of a second, the programm will pick a random LED and assign a random colour to it.

I know the library is lacking the nice `set_pixel(x, y, r, g, b)` and all the other high level functions. But it is not that hard to implement.

Now I’m trying to find how I could use this for a real life application :-D

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<div class="post-metadata">

**Author:** ![RogueM](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.pimoroni.com/roguem/32/311_2.png) [@RogueM](https://forums.pimoroni.com/u/RogueM)\
**Post date:** [September 30, 2016, 4:24pm UTC](https://forums.pimoroni.com/t/unicorn-phat-with-nodejs/3113/2 "2016-09-30T16:24:36Z")

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Cheers for that. You may also be interested in:

> **[pimoroni/node-red-nodes](https://github.com/pimoroni/node-red-nodes)**
>
> node-red-nodes - Node-RED nodes for Pimoroni products

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<div class="post-metadata">

**Author:** ![jason](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.pimoroni.com/jason/32/1645_2.png) [@jason](https://forums.pimoroni.com/u/jason)\
**Post date:** [September 30, 2016, 4:48pm UTC](https://forums.pimoroni.com/t/unicorn-phat-with-nodejs/3113/3 "2016-09-30T16:48:01Z")

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Thanks, I didn’t know Node-RED.  
Interesting!