rpi-ws281x-v2

This is a npm module for connecting a Raspbery Pi to Neopixel strips. It uses the
library from jgarff https://github.com/jgarff/rpi_ws281x.

Installation

```bash
$ npm install rpi-ws281x-v2 --save
``

Usage

``javascript

var ws281x = require('rpi-ws281x-v2');

// One time initialization
ws281x.configure({leds:16});

// Create my pixels
var pixels = new Uint32Array(16);

// Render pixels to the Neopixel strip
ws281x.render(pixels);

``

Methods

This module is simple and only has three methods configure(), render() and reset().

- configure(options) - Configures the ws281x strip. Must be called once and before anything else. See
examples below.
- render(pixels) - Renders the pixels specified to the strip. The pixels parameter must
be an Uint32Array representing the color values of all pixels
and the same size as the number of leds specified when configuring.
- reset() - Resets configuration.

Examples

$3

``javascript

var ws281x = require('rpi-ws281x-v2');

class Example {

constructor() {
this.config = {};

// Number of leds in my strip
this.config.leds = 169;

// Use DMA 10 (default 10)
this.config.dma = 10;

// Set full brightness, a value from 0 to 255 (default 255)
this.config.brightness = 255;

// Set the GPIO number to communicate with the Neopixel strip (default 18)
this.config.gpio = 18;

// The RGB sequence may vary on some strips. Valid values
// are "rgb", "rbg", "grb", "gbr", "bgr", "brg".
// Default is "rgb".
// RGBW strips are not currently supported.
this.config.strip = 'grb';

// Configure ws281x
ws281x.configure(this.config);
}

run() {
// Create a pixel array matching the number of leds.
// This must be an instance of Uint32Array.
var pixels = new Uint32Array(this.config.leds);

// Create a fill color with red/green/blue.
var red = 255, green = 0, blue = 0;
var color = (red << 16) | (green << 8)| blue;

for (var i = 0; i < this.config.leds; i++)
pixels[i] = color;

// Render to strip
ws281x.render(pixels);
}

};

var example = new Example();
example.run();

``

$3

``javascript

var ws281x = require('rpi-ws281x-v2');

class Example {

constructor() {
// Current pixel position
this.offset = 0;

// Set my Neopixel configuration
this.config = {leds:169};

// Configure ws281x
ws281x.configure(this.config);
}

loop() {
var pixels = new Uint32Array(this.config.leds);

// Set a specific pixel
pixels[this.offset] = 0xFF0000;

// Move on to next
this.offset = (this.offset + 1) % this.config.leds;

// Render to strip
ws281x.render(pixels);
}

run() {
// Loop every 100 ms
setInterval(this.loop.bind(this), 100);
}
};

var example = new Example();
example.run();

``

$3

``javascript

var ws281x = require('rpi-ws281x-v2');

class Example {

constructor() {
// Current pixel position
this.offset = 0;

// Set my Neopixel configuration
this.config = {};

// By setting width and height instead of number of leds
// you may use named pixel mappings.
// Currently "matrix", "alternating-matrix",
// "serpentine-matrix" and "canvas-matrix" are supported.
// You may also set the "map" property
// to a custom Uint32Array to define your own map.
this.config.width = 13;
this.config.height = 13;
this.config.map = 'alternating-matrix';

// Configure ws281x
ws281x.configure(this.config);
}

loop() {
var leds = this.config.width * this.config.height;
var pixels = new Uint32Array(leds);

// Set a specific pixel
pixels[this.offset] = 0xFF0000;

// Move on to next
this.offset = (this.offset + 1) % leds;

// Render to strip
ws281x.render(pixels);
}

run() {
// Loop every 100 ms
setInterval(this.loop.bind(this), 100);
}
};

var example = new Example();
example.run();

```