Hi there,
I'm trying to control a LED indicator board via Processing. Opening a connection and sending text works perfectly. But the board is also capable of displaying simple graphic data.

This is the board I'm working on: LED board and here's a link to the data sheet

If I'm sending simple text to the board, everything displays nicely. But if I'm trying to send graphic data, the board turns black and a few LEDs light up randomly for maybe a second. The previous contents seem to be replaced, but the replacement seems to contain incorrect data.

A working text message looks like this:

1. <ID01><L1><PA><FE><MA><WA><FE><AA><N00>My text goes here2E<E>

<ID01> specifies the ID of the LED board, all other <> tags specify pre-set effects (like animation-in, animation-out, etc.). The 2E is the checksum of the text, <E> is the end tag.

The data sheet (p. 13-14) says, that a graphic block basically is build the same way.

1. <Gxn>..Graphic data
   

e.g.

1. <GA1> Graphic data

So I thought a successful data package should look something like this:

1. <ID01<GA1>10000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000000000000000000000000000000000000000000000000000000000000000000000000000000000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000100000000000000000000000000000000000000000000000000000000000000000000000000000000000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000001000000000000000000000000000000000000000000000000000000000000000000000000000000000000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000010000000035<E>
2. <ID01><BE><L1><PA><FA><MA><WA><FA><GA1>46<E>
   

The LED board came with a little helper tool called "NewSign 03127 or 03128". I logged communcations between the tool and the LED board using a USB port monitor. This is an excerpt how the data of a Graphic block looks like then:

1. <ID01><GA1>¨ ¨*(((*(*        ¨ª¨ª  ª ª ª BD<E>

Does anyone have a clue how the message has to be built? What am I doing wrong? Any hints are highly appreciated!

Hi guys,

so I'm trying to control a LED indicator board via Processing. Opening a connection and sending text works perfectly. But the board is capable of displaying simple graphic data.
The data sheet (which can be found here: data sheet) explains on pages 13-14 how a message has to be constructed:

Each Graphic Block built by 4 8x8 dots units
Sequence of data is shown below.

Graphic data mapping
Graphic Pixels: D0,D1,D2,...D255, four Pixel is represented by 1 Byte.
Byte 1 = D0..D3
Byte 2 = D4..D7
Byte 3 = D8..D11
...
Byte 63 = D252..256
Structure of each Data : Each Pixel composite by 2 bit. MSB is the most Left Bit
e.g. the first dot is RED ,the second dot is GREEN, the third dot is yellow and the forth dot is black.

Data = 10 01 11 00
              |    |    |    |
              |    |    |    -Black
              |    |    ----- Yellow
              |    --------- GREEN
              ------------ RED

I got 3 questions of which I'm hoping someone can explain:

1. As I understand the explanations, there is a "layout helper thing" called Graphic Block. One Graphic Block consists of 4 8x8 dots units. Inside one of the 4 8x8 units the graphic pixels are denoted left to right and row by row (see image). Four of these graphic pixels are represented by one byte. Every single pixel consists of 2 bit ("colour management"). Did I get the theoretical background right so far? And could someone explain to me, what exactly one LED is in this whole description? A "dot"?
   
2. The data sheet obviously was made for two different products - single colour and multi-colour LED boards. Mine consists of red LEDs only. How is the data structure supposed to look like then? 10 10 10 10?
3. I have no idea how to transfer all this theoretical background into code. Can you help me getting started please?

Looking forward to your replies, any help and suggestions is highly appreciated!

I am programming an application to communicate with a LED indicator board. A typical request looks like this:

1. <ID01><L1><PA><FE><MA><WC><FE>Probe3E<E>

where 3E is the checksum for the code in front of the checksum. The LED documentation says that the checksum "denotes the Xor Result of the data content". I'm not exactly a coding ninja, so I can't quite figure out how to code this.

I found an allegedly working example coded in Delphi and tried to adopt it to Processing, but this doesn't seem to result in a correct checksum:

1. String myCommand = "<ID01><L1><PA><FE><MA><WC><FE>Probe"; // result should be: 3E
   byte res = 0;
   for(int i=0; i<myCommand.length(); i++){
     res ^= byte(myCommand.charAt(i));
   }
   String checksum = hex(res);

Thanks for your help!

Hi there,

I want to send data to this LED board: http://www.conrad.de/ce/de/product/590998/LED-LAUFSCHRIFT-ROT
The data sheet is available here: http://www.produktinfo.conrad.com/datenblaetter/575000-599999/590998-da-01-en-LED_LAUFSCHRIFT_ROT.pdf

To get started I had a look at the forums and found this topic: http://forum.processing.org/topic/processing-brg-led-display-signs where zach.gage posted some code, how he managed to talk to a LED sign by a different manufacturer.

The problem is that he connected the sign via parallel port, but I got a USB connection. So I am trying to figure out how I can send data to the device via USB.

Any ideas on how I can get started?