README
¶
go-rpi-ws281x 
golang binding for rpi_ws281x, userspace Raspberry Pi PWM library for WS281X LEDs. Supports any Raspberry and WS2812, SK6812RGB and SK6812RGBW LEDs strips, this includes Unicorn pHAT and NeoPixels
This is a Fork of github.com/mcuadros/go-rpi-ws281x.
Installation
go get (recommended)
The recommended way to install go-rpi-ws281x is to first install rpi_ws281x on your system. Please follow the instructions given in their README.md.
go-rpi-ws281x will look for the library in the system folders "/usr/local/lib" and "/usr/local/include/ws2811".
Now download this package and add it to your go.mod file with:
go get github.com/DerLukas15/go-rpi-ws281x
git clone
If you want to clone this repository instead of using go get you can also run make build in the main folder to download and compile rpi_ws281x locally. However you will then need to supply a replace statement in your go.mod file pointing to your local copy.
Optionally run make install-rpi_ws281x as root to install rpi_ws281x in the system folders.
Cross compilation for ARM
In order for valid library files for a ARM compilation, rpi_ws281x has to be build with additional arguments. go-rpi_ws281x includes special CGO lines for arm. For this to work the rpi_ws281x library has to be named libws2811arm.a instead of libws2811.a.
Install the required C compiler arm-linux-gnueabihf-g++ and arm-linux-gnueabihf-gcc via your distribution package manager.
Don't forget to set CGO_ENABLED=1 GOOS=linux GOARCH=arm GOARM=5 CC=arm-linux-gnueabihf-gcc CXX=arm-linux-gnueabihf-g++ during the build of your application.
go get
When using go get build rpi_ws281x from source with cmake following their README.md. During the compilation replace the line:
cmake -D BUILD_TEST=OFF -D BUILD_SHARED=OFF .
with
cmake -D CMAKE_C_COMPILER=arm-linux-gnueabihf-gcc -D CMAKE_CXX_COMPILER=arm-linux-gnueabihf-g++ -D BUILD_TEST=OFF -D BUILD_SHARED=OFF .
and rename the library after make install:
mv /usr/local/lib/libws2811.a /usr/local/lib/libws2811arm.a
Be aware that the install will overwrite an existing libws2811.a file. So either copy the file by yourself instead of make install or build the other architecture afterwards. The header files do not have to be changed between architectures.
Everything else follows the normal way as shown above.
git clone
When cloning this repo you can run make build-arm in the main folder to create the ARM library. For an optional installation in the system folders run make install-rpi_ws281x-arm as root.
Everthing else follows the normal way as shown above.
Examples
// create a new canvas with the given width and height, and the config, in this
// case the configuration is for a Unicorn pHAT (8x4 pixels matrix) with the
// default configuration
c, _ := ws281x.NewCanvas(8, 4, &ws281x.DefaultConfig)
// initialize the canvas and the matrix
c.Initialize()
// since ws281x implements image.Image any function like draw.Draw from the std
// library may be used with it.
//
// now we copy a white image into the ws281x.Canvas, this turn on all the leds
// to white
draw.Draw(c, c.Bounds(), image.NewUniform(color.White), image.ZP, draw.Over)
// render and sleep to see the leds on
c.Render()
time.Sleep(time.Second * 5)
// don't forget close the canvas, if not you leds may remain on
c.Close()
Check the folder examples folder for more examples
License
MIT, see LICENSE
Documentation
¶
Index ¶
- Variables
- type Canvas
- func (c *Canvas) At(x, y int) color.Color
- func (c *Canvas) Bounds() image.Rectangle
- func (c *Canvas) Clear() error
- func (c *Canvas) Close() error
- func (c *Canvas) ColorModel() color.Model
- func (c *Canvas) Initialize() error
- func (c *Canvas) Render() error
- func (c *Canvas) Set(x, y int, color color.Color)
- type HardwareConfig
- type Matrix
- type StripType
- type WS281x
Constants ¶
This section is empty.
Variables ¶
var DefaultConfig = HardwareConfig{ Pin: 18, Frequency: 800000, DMA: 10, Brightness: 30, StripType: StripGRB, }
DefaultConfig default WS281x configuration
Functions ¶
This section is empty.
Types ¶
type Canvas ¶
type Canvas struct {
// contains filtered or unexported fields
}
Canvas is a image.Image representation of a WS281x matrix, it implements image.Image interface and can be used with draw.Draw for example
func NewCanvas ¶
func NewCanvas(w, h int, config *HardwareConfig) (*Canvas, error)
NewCanvas returns a new Canvas using the given width and height and creates a new WS281x matrix using the given config
func (*Canvas) ColorModel ¶
ColorModel returns the canvas' color model, always color.RGBAModel
func (*Canvas) Initialize ¶
Initialize initialize the matrix and the canvas
type HardwareConfig ¶
type HardwareConfig struct {
Pin int // GPIO Pin with PWM alternate function, 0 if unused
Frequency int // the frequency of the display signal in hertz, can go as low as 400000
DMA int // the DMA channel to use
Invert bool // specifying if the signal line should be inverted
Channel int // PWM channel to use
Brightness int // brightness value between 0 and 255
StripType StripType // strip color layout
}
HardwareConfig WS281x configuration
type Matrix ¶
type StripType ¶
type StripType int
StripType layout
const ( // 4 color R, G, B and W ordering StripRGBW StripType = 0x18100800 StripRBGW StripType = 0x18100008 StripGRBW StripType = 0x18081000 StripGBRW StripType = 0x18080010 StripBRGW StripType = 0x18001008 StripBGRW StripType = 0x18000810 // 3 color R, G and B ordering StripRGB StripType = 0x00100800 StripRBG StripType = 0x00100008 StripGRB StripType = 0x00081000 StripGBR StripType = 0x00080010 StripBRG StripType = 0x00001008 StripBGR StripType = 0x00000810 )
type WS281x ¶
type WS281x struct {
Config *HardwareConfig
// contains filtered or unexported fields
}
WS281x matrix representation for ws281x
func (*WS281x) At ¶
At return an Color which allows access to the LED display data as if it were a sequence of 24-bit RGB values.
func (*WS281x) Initialize ¶
Initialize initialize library, must be called once before other functions are called.
Source Files
Directories