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WS2812 Server is a program for driving programmable LEDs like the WS2812 or SK9822 from your Raspberry Pi. It is based on the rpi_ws281x PWM driver library from jgarff (
LEDs can be controlled by using simple predefined text commands, no advanced programming skills are required.

Some features:

  • Control LEDs from text file using predefined effect commands
  • Run as a service in the background
  • Send commands over TCP socket or named pipe to connect with other applications or programming languages like Python, C# or PHP webserver
  • Make LEDs react to audio input
  • Support for 2D LED panels
  • Capture desktop or directly or load JPG, PNG and GIF files
  • Create a message board
  • Use the Raspberry Pi PWM, PCM or SPI interface
  • Capture and display video from Pi camera module or HDMI USB capture device.
  • Capture video and generate ambilight for your TV!
  • Master - Slave mode, let 1 Pi control LED strings connected to multiple other Pis over Wifi/Ethernet.

Read the change log to see what is new:

Support for Master-Slave


Supported chips

You can use this with the WS2811, WS2812, SK6812, SK9822 chips.


If you are using the Raspberry Pi OS with desktop enabled the audio output is activated by default. This audio interface uses the PCM/PWM module which is required to drive the LEDs (ws2812 / SK6812) so you need to disable default audio output first. You can do this by blacklisting the sound module:

echo "blacklist snd_bcm2835" | sudo tee /etc/modprobe.d/snd-blacklist.conf

If this doesn't work, also comment out the dtparam=audio=on parameter in /boot/config.txt

sudo sed -i "s/^dtparam=audio=on/#dtparam=audio=on/g" /boot/config.txt

Standard installation with support for all features use the following commands:

sudo apt-get update
sudo apt-get install gcc make git libjpeg-dev libpng-dev pkg-config libasound2-dev libcairo2-dev libx11-dev libxcb1-dev libfreetype6-dev libv4l-dev v4l-utils
git clone
cd rpi-ws2812-server
sudo chmod +x ws2812svr

Now you can start testing or install the program as a service (automatic startup). To install as a service use:

sudo make install

A new service will be added (ws2812svr), edit /etc/ws2812svr.conf to configure the settings.


Connect your LEDs to the PWM output (default is physical pin 12 on the connector) of the Raspberry Pi and start the program:

sudo ./ws2812svr

Now first initialize the driver code from jgarff by typing 'setup'. On the following line you must replace 10 by the number of leds you have attached!.

setup 1,10

Now you can type commands to change the color of the leds. For example make them all red:

fill 1,FF0000


You can find examples in the examples folder.

On Youtube:
video control with smartphone

Example effects video

Visual Studio Code integration

Install the Visual Studio Code extension to get syntax highlighting and autocompletion when writing scripts. Demo

Search for ws2812svr extension in your Visual Studio Code IDE and save file with the .ws extension.


It is possible to start threads, a thread will execute commands between thread_start and thread_stop in the background. Multiple threads can run at the same time by changing the parameter. <join_type> will determine the behavior next time you call thread_start with the value of a thread that is still running if join_type is 0 the thread will be aborted immediately, value of 1 it will wait until the thread completed all commands and then READY + CRLF is returned.

thread_start <index>,<join_type>
		rotate 1,1,2
		delay 200

Thread commands

For a complete list and description of all supported commands see the file.

  • set_thread_exit_type This will set if the thread should be aborted when the kill_thread or ini_thread command is executed for the <thread_id> parameter
  • wait_thread wait for a given thread to finish all commands (the exit type is ignored here)
  • kill_thread terminate the given thread_id
  • wait_signal waits for a signal from another thread before executing the next command
  • signal_thread send a signal to the given thread_id to continue executing commands

Special keywords

You can add do ... loop [times] to repeat commands.

For example the commands between do and loop will be executed 10 times:

	<enter commands here to repeat>
loop 10

Endless loops can be made by removing the '10'. Inside a loop you can use {i} for the loop counter as function argument where i is the nested loop index.

For example {0} will be automatically replaced by 0,1,2,3,4:

	fill 1,FF0000,{0},1
loop 5

is the same as the C-style code:

for (i=0; i<5; i++) {
	fill (1,FF0000,i,1);

If you have nested loops you can increase the {0} to {1}, {2},...

		fill 1,FF0000,{1},1
	loop 5

Also possible to add a step value for the loop index to fill every "even" led

	fill 1,FF0000,{0},1
loop 5,2

is the same as:

for (i=0; i<5; i+=2) {
	fill (1,FF0000,i,1);

To create an alternating pattern of colors use rotate commands in a loop. For a 300 LED string this will create alternating RED-YELLOW-GREEN-BLUE-PINK colors:

	rotate 1,1,1,FF0000
	rotate 1,1,1,FFFF00
	rotate 1,1,1,00FF00
	rotate 1,1,1,0000FF
	rotate 1,1,1,FF00FF
loop 60

PHP example

First start the server program in TCP mode:

  • sudo ./ws2812svr -tcp

Then run the php code from the webserver (check on google how to setup a webserver PHP+APACHE or PHP+NGINX on your Pi):

// Create a rainbow for 10 leds on channel 1:

send_to_leds("setup 1,10;init;brightness 1,32;");

function send_to_leds ($data) {
	$sock = fsockopen("", 9999);
	fwrite($sock, $data);

Command line parameters

# Listens for clients to connect to port 9999 (default).
sudo ./ws2812svr -tcp 9999`

# Loads commands from a text file
sudo ./ws2812svr -f text_file.txt

# Creates a device called /dev/ws281x where you can write you commands to with any other programming language (do-loop not supported here).
sudo ./ws2812svr -p /dev/ws281x

# Initializes with command setup 1,4,5 and command init it
sudo ./ws2812svr -i "setup 1,4,5; init;"

# Loads with settings from a config file
sudo ./ws2812svr -c /etc/ws2812svr.conf

Running as a service

To run as service run make install after compilation and adjust the config file in /etc/ws2812svr.conf

sudo make install

After installing service it will run by default in TCP mode on port 9999, if you want to change this you must edit the config file:

sudo nano /etc/ws2812svr.conf

Change the mode to: tcp for TCP mode (change the port= setting) file for file mode (change the file= setting for location of file) pipe for named pipe mode (change the pipe= setting for the location of the named pipe) mode must be first setting in the conf file! init setting can be used to initialize the led count and type fill color,...


General Commands

For a complete list and description of all supported commands see the file.

  • setup setup LED string type / LED count, command must be called everytime the program is started, before init command.
  • init Must be called after all setup commands to initialize the hardware.
  • slave_listen Listens for incoming connection from master Pi, returns when connection is lost/closed.
  • save_state saves current color and brightness values of a channel to a CSV file, format is.
  • load_state loads saved color and brightness values from CSV file. see save_state for format.
  • reset reset all initialized led strings, ready for new setup commands
  • render command sends the internal buffer to all leds
  • rotate command moves all color values of 1 channel
  • rainbow command creates rainbows or gradient fills
  • fill command fills number of leds with a color value
  • delay command waits for number of milliseconds
  • brightness command changes the brightness of a single or multiple leds without changing the actual color value
  • fade command changes the brightness over time
  • gradient command makes a smooth change of color or brightness level in a channel
  • random command can create a random color
  • readjpg command can read the pixels from a JPEG file and fill them into the LEDs of a channel
  • readpng command can read the pixels from a PNG file and fill them into the LEDs of a channel
  • blink command makes a group of leds blink between 2 given colors
  • random_fade_in_out creates some kind of random blinking/fading leds effect
  • color_change slowly change all leds from one color to another
  • chaser makes a chaser light
  • fly_in fill entire string with given brightness level, moving leds from left/right untill all leds have brightness level or a given color
  • fly_out fill entire string with given brightness level, moving leds from left/right untill all leds have brightness level or a given color
  • progress generates a progress bar effect or sets the leds brightness to a given progress value
  • ambilight Capture video from USB HDMI capture card or Raspberry camera and generate ambilight for your TV

2D LED panel support

Support for multiple 2D connected WS2812 LED panels is added since version 5.3 2D graphics are rendered using cairo (, first a 1D led string channel must be initialized with total LEDs in your 2D matrix. Next you call config_2D which will initialize cairo surface / layers and attach them to the 1D led string. After this calling render on the channel will flush the cairo surface to the 1D led string and render it to the leds. Executing 1D effects on a 2D configured channel will have no effect.

Hello world 2D

2D graphics layers

By default only the bottom layer is initialized but it's possible to initialize more layers and change the layer the 2D commands will paint to. The render command will then paint all layers to the bottom layer where the top most layer has tkhe priority. The result will be send to the 1D string and to LEDs. It's possible to load a PNG file as background on the bottom layer and paint shapes or text on top of it using a second layer. Clear text layer and paint something else without having to redraw the entire PNG and shapes.

2D Commands

For a complete list and description of all supported commands see the file.

  • config_2D configure 2D LED matrix (requires compile with ENABLE_2D=1)
  • init_layer Initializes a new 2D graphics cairo layer or change layer settings
  • change_layer changes the current layer 2D cairo graphics are painted to
  • draw_circle Draws a circle or arc (cairo_arc) on the current selected layer
  • cls Fills current layer with a color
  • draw_image draws an image file
  • draw_line draws an image file
  • draw_sharp_line draws an image file
  • draw_rectangle draws and fills a rectangle
  • message_board makes a scrolling message
  • print_text prints text, uses cairo_show_text
  • text_input prints scrolling text which is send to a TCP socket listening on port_nr
  • set_pixel_color Sets a pixel to a color
  • camera Captures frames from a v4l2 MJPEG camera (Raspberry Pi camera or HDMI USB capture card). Prints this to the 2D matrix.

Audio input

Since version 6.1 it's possible to make LEDs react to audio input. This audio will be captured from an ALSA sound device (USB sound card,...). Before you can use any of the audio commands you first need to start recording, you can do so with the record_audio command. NOTE: if you want to use multiple threads each thread needs to run the record_audio command before you can use the audio effect commands.

  • record_audio records audio

Audio effects

First start the record command (see above), then you can use these commands to make LEDs react to audio input.

Audio commands

For a complete list and description of all supported commands see the file.

  • light_organ Generates a light organ, alle LEDs blink to the rhythm of the music.
  • pulses Generates wave pattern on the LED strip (like a music driven chaser)
  • vu_meter Generates a volume meter effect