garyhung525 / pi-ws2812

Java WS2812 LED Driver

Pi WS2812 LED Driver

A Java library to drive the popular WS2812 RGB LED from a Raspberry Pi. E.g. the unicorn-hat is a 8x8 array of those WS2812 RGB LEDs (https://shop.pimoroni.com/products/unicorn-hat)

This is a simple wrapper around Pimoroni's C library using JNA to relay the calls. The original C library is here:

https://github.com/pimoroni/unicorn-hat

For the moment this was just tested with Raspberry Pi B+ and not Raspberry Pi2. The enclosed c library is compiled with the GPIO memory location of model 1, so this most likely won't work with model 2 yet.

how to use?

First you need to clone and compile the library using Maven and then you can use the library in your maven projects like this:

<dependency>
    <groupId>de.pi3g.pi</groupId>
    <artifactId>pi-ws2812</artifactId>
    <version>1.0-SNAPSHOT</version>
</dependency>

The hardware needs to be connected to GPIO port #18 which has hardware PWM (which is needed here as the WS2812 has singal lengths of about 1.25us)

Then you can use the library like this:

WS2812.get().init(64); //init a chain of 64 LEDs
WS2812.get().clear();    
WS2812.get().setPixelColor(0, Color.RED); //sets the color of the fist LED to red
WS2812.get().show();

Note that you always need to call show() after you changed the color of any LED to publish the changes to the hardware.

how to build?

The entire project is build with maven. Just clone the master branch, open the directory in NetBeans and hit run. Or if you prefer the command line:

mvn install

should build everything correctly.