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DIY LED Array Marquee For Your PC 128

Posted by kdawson
from the geeking-out-on-the-weekend dept.
An anonymous reader writes "Ever wish you had one of those big LED displays to keep you up to date on e-mails, stock quotes, server uptimes, or weather? Here's a new video tutorial showing how to build your own computer-controlled LED array. You can code your own data feed, and just send it over a TCP socket. This looks like a fun weekend project for someone looking to get started with electronics by building something useful."
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DIY LED Array Marquee For Your PC

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  • Now... (Score:5, Interesting)

    by Spazztastic (814296) <> on Friday January 23, 2009 @02:24PM (#26577993)
    The question is if I can do this and have it run from my car. I put in predefined phrases, and depending on which switch I hit or button, it says them?
  • Small version (Score:3, Interesting)

    by Hogwash McFly (678207) on Friday January 23, 2009 @03:02PM (#26578655)

    My boss gave me a USB-powered LED screen as a Christmas present, aimed as one of those endless throwaway novelty USB gadgets (other one was a whack-a-mole game. It's far smaller than the one in TFA though, about the size of a pack of smokes. Still, it scrolls text and displays bitmaps pretty niftily. The font and configuration files are stored in plain text (the scroll speed was a fun one to tweak) so the option for even-triggered (e.g. server in trouble) scripting is there.

    Granted, there's no geek cred from building it yourself, but at least the soft aspect is similar. Now if only there support calls would stop coming in so fast that I had time to play with the thing...

  • by jtara (133429) on Friday January 23, 2009 @03:08PM (#26578775)

    I wrote the firmware for one of these thingies about 20 years ago. (I did it for a company that was in the electronic sign business - they made those flip-dot signs you see on buses, subways, etc.) I was lucky to have been given pretty-much complete flexibility in the firmware design, including functionality.

    We used a Z-80 as the controller. The display panel was built on two identical circuit boards - they could be chained endlessly, though I don't think they ever made a wider model. It was a BIG DEAL getting the component-stuffing machine to place all those LEDs! (This wasn't surface mount, but through-holes.)

    Each display panel had a shift-register - one bit per column, and just passed the bits down to the next panel. The CPU banged out bits to the shift register until the row was filled, and then enabled the row driver. Yes, we were careful to avoid refresh rates that could be a problem for epileptics.

    They insisted on an asymmetrical case design - the case had a "base" that it could sit on on a desk or other surface, or it could be mounted from a ceiling. Only problem was, if it was mounted from a ceiling, it was then "upside down" and the characters had to be flipped. They were going to put a switch on the back, but I figured they would get support calls from people who wouldn't read the manual, so at my suggestion they put in a mercury switch, mounted at a 45 degree angle. The processor read the mercury switch and flipped the characters if needed.

    We used an RCA flat-panel keyboard with a custom overlay. I designed icons for the various effects, and the icons were printed over letters and accessed during programming with the "ALT" key. The icons appeared on screen when in programming mode. There was a simple text-editor, and some icons accepted parameters (for example, transition effects all took an optional transition time parameter) I implemented a simple macro system [macro_name] so that text snippets could be stored and referenced from within messages. You could store multiple messages and select the one or ones to be displayed, or a timer could trigger them.

    There was also a serial port through which it could be programmed. I think the idea was that it could be programmed remotely in, say, a store location. I don't know if this was ever implemented, but I vaguely recall that the idea was to send a subcarrier signal on a muzak station (that stores would already have access to) that would be decoded and passed to the serial port.

    I never did install one of these in the back window of my car. I certainly entertained the thought, though. :)

    I had one of the pre-production samples kicking around for years, and finally discarded it. Yea, I wish I still had that Schelbi Mark 8 too... (Mine was build on a wirewrap board - somebody was selling a kit with a wirewrap board and all the parts).

    (Would be interesting to compare the designs. However, the site referenced by the article has been slashdotted...)

  • by linhux (104645) on Friday January 23, 2009 @03:55PM (#26579509) Homepage

    "Ever wish you had one of those big LED displays to keep you up to date on e-mails, stock quotes, server uptimes, or weather?

    Yeah, I used to wish exactly that, but I took the easy (well, I did have to reverse-engineer the serial protocol, but that was fairly easy) way out and went to the hardware store and bought one. It's been serving my team very well since then []. :-)

  • by NixieBunny (859050) on Friday January 23, 2009 @07:19PM (#26582811) Homepage

    I found a couple hundred big 8x8 matrix LED displays on ebay for way too little money last year, and I'm working on a low-resolution but huge flat TV for video fun at Burning Man this summer.

    But I'm going with a standard video signal such as your DVD player makes, so it will display shades of gray for realistic reproduction of video images.

    It's a bit tricky to make a TV display out of LEDs, but I found that using a couple dozen FPGAs makes the job a lot easier. Pulse width modulation provides the brightness control per pixel.

    It should be a lot of fun when completed. I';ll post photos.

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