cluesang/node-opc-server

Open Pixel Control protocol for WS281x LEDs on Raspberry Pi

node-opc-server

Open Pixel Control protocol parser

node-opc-server implements the Open Pixel Control protocol and drives ws281x RGB LEDs using the rpi-ws281x-native library.

System overview

 PC or Raspi running -> Network -> Raspi #18 -> 3.3V -> 5V -> NeoPixel
 grid8x8_dot.pde                                              8x8 array

• Drives one WS2812 LED strip up to 1024 LEDs but only tested up to 128 LEDs.

• Implements the Open Pixel Control protocol on TCP port 7890. This is the same protocol used by Fadecandy server (fcserver).

This is not a Fadecandy controller hardware clone. Fadecandy has advanced features not implemented by this program.

• No dithering.
• No keyframe interpolation.
• Fixed gamma correction of 2.2
• SysEx ignored.

Use it

I recommend running Raspian Jessie.

Install node 4.2.1 (as of March 8, 2016) from http://node-arm.herokuapp.com/.

wget http://node-arm.herokuapp.com/node_latest_armhf.deb
sudo dpkg -i node_latest_armhf.deb
node -v

Install this package.

npm install node-opc-server
cd node_modules/node-opc-server/opc-server
npm install
sudo node index.js

Example programs to drive the LEDs

Many open pixel control and Fade Candy examples work with node-opc-server. If the example code is not running on the Raspi running opc-server, be sure to modify the examples with the Raspi IP address.

The following examples from https://github.com/zestyping/openpixelcontrol work.

python\_clients/
    lava_lamp.py,miami.py,nyan_cat.py,sailor_moon.py,spatial_stripes.py

$ ./lava\_lamp.py -l grid8x8.json -s <Raspi IP addr>:7890 -f 30

The Fadecandy grid8x8 Processing examples at https://github.com/scanlime/fadecandy work with this program. These examples show how to create interactive LED displays. Edit the PDE file to add the Raspi IP address.

examples/processing/
    grid8x8_dot, grid8x8_noise_sample, grid8x8_orbits, grid8x8_wavefronts

Changes

v1.0.4 Verified to work on a Raspberry Pi 2, Raspian Jessie, and nodejs 4.2.1 from http://node-arm.herokuapp.com/

References

The rpi-ws281x-native library is used to drive the WS281x LEDs. See https://www.npmjs.com/package/rpi-ws281x-native for more details.

See https://github.com/zestyping/openpixelcontrol for the OPC protocol specification.

The following Adafruit LED art tutorial covers wiring and powering the LEDs, etc. In addition, it covers installing and running Fadecandy example programs.

https://learn.adafruit.com/led-art-with-fadecandy/