Toms Online Notebook Sharing my stuff.

LedNet Proxy

by tgutwin

Posted on Sunday Dec 18, 2016 at 06:40PM in Programming

LedNet-5Wire.jpgI want to control a LED light Strip with the 5 channel (rgbw) LEDNet controller that I bought.  I want to use my own software. Thankfully others have figured out the IP messaging packet, so I wrote my own little app that lets me program/control a Strip of RGBw LEDs.

The ultimate intent is to be able to control it using My UDI ISY-994 home controller. I can actually do this already using the Network Resources plugin, BUT it is a bit slow to respond. So i want to directly control it with a Java app and have the ISY call pre-made routines in it so it functions quicker. This Java app must also be a IP listener, to respond to requests from the ISY.

Its all do-able.

Message Format


Based on the post at the UDI Forum;
here is the messaging format for a SetColour Message; 13 Base10 chars:

  1. 49
  2. R (0-255)
  3. G (0-255)
  4. B (0-255)
  5. WW (0-255)
  6. CW (0-255) (only needed for the 5 channel model, omit for the 4 channel model)
  7. 0
  8. 15
  9. checkSum = sum (lowest byte ONLY) of the 1st 8 chars (or 7 chars for the 4 channel model)
  10. 129
  11. 138
  12. 139
  13. 150

NOTE: there is a 4 channel model available, that has one less char/byte in the message (and one less byte/char included in the checksum)

The associated UDI ISY-994 Network Resource string:
Red:   49;255;0;0;0;0;0;15;63;129;138;139;150
Green: 49;0;255;0;0;0;0;15;63;129;138;139;150
Blue:  49;0;0;255;0;0;0;15;63;129;138;139;150
White: 49;0;0;0;0;255;0;15;63;129;138;139;150
Cyan:  49;0;255;255;0;0;0;15;62;129;138;139;150

NOTE: that the CYAN checksum wraps to 2 bytes so only the low byte (62) is sent.

Here is the messaging format for the On/Off Message; 8 Base10 chars:

  1. 113
  2. 35 (or 36 for Off)
  3. 15
  4. checkSum = sum of the 1st 3 chars  (163 for on, 164 for off)
  5. 129
  6. 138
  7. 139
  8. 150

The associated UDI ISY-994 Network Resource string:
ON:   113;35;15;163;129;138;139;150
OFF: 113;36;15;164;129;138;139;150

The detailed messages available have been documented in the ledNet_MessageSyntax.txt file.


Here is the Java code I use to construct the message string that gets directly sent to the LedNET:

  public StringBuilder getLedNetColourMessage(int r, int g, int b, int w)
    String cmdStr = "";
    int chkSum = r+g+b+w+49+15;

    else if(chkSum>(3*256))
    else if(chkSum>(2*256))
    else if(chkSum>(256))

    StringBuilder sb = new StringBuilder();

    /* This is where I construct the entire message character by character. */
    sb.append((char)Integer.parseInt("49", 10));

    // 3 char for R G B
    sb.append((char)Integer.parseInt(""+r, 10));
    sb.append((char)Integer.parseInt(""+g, 10));
    sb.append((char)Integer.parseInt(""+b, 10));

    // 1 char for Warm White (mine is not connected)
    sb.append((char)Integer.parseInt(""+0, 10));
    // 1 char for Cold White
    sb.append((char)Integer.parseInt(""+w, 10));

    // a zero
    sb.append((char)Integer.parseInt(""+0, 10));
    // a 15 to end content
    sb.append((char)Integer.parseInt(""+15, 10));

    // low byte/ char for checkSum
    sb.append((char)Integer.parseInt(""+chkSum, 10));

    // msg end
    sb.append((char)Integer.parseInt(""+129, 10));
    sb.append((char)Integer.parseInt(""+138, 10));
    sb.append((char)Integer.parseInt(""+139, 10));
    sb.append((char)Integer.parseInt(""+150, 10));

    return sb;
  }  //getLedNetColourMessage

Note: I use parseInt in case I want to use HEX values, in that case I would switch the 10 to a 16

Sending the Message

Empirically, I found the message took about 505ms to send and allow me to send another.

Here is the Java code to send the message to a a previously created ObjectOutputStream connected to the LedNet IP Socket:

  public void sendColourCommand(int r, int g, int b, int w, boolean closeSocket)
    StringBuilder sb = getLedNetColourMessage(r,g,b,w);
    boolean verbose = false;
    if(connectSocket()) // sets up out_ -an ObjectOutputStream already connected to the LedNet IP Socket
        if(verbose)System.out.println("  sending "+sb.length() +" chars: ");
        /* out_ has already been created and connected to the LedNet IP Socket */
        out_.writeBytes(sb.toString());  // <--- This is the one that works
        if(verbose)System.out.println("sent!" );
        /* now listen for the response. */
        Vector <String> rv = null;
        rv = readQueryResponses();
      catch(IOException ioException)
    if (closeSocket) closeSocket();

Thats it... now play around.

CupOfJava.jpgFull Java Code:


LedNet Device

No one has commented yet.

Leave a Comment

HTML Syntax: NOT allowed