monitor to LED

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Joined: Oct 10 2005
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I used specific electronics that was developed to control 256 leds trought serial port in real time. Now i need something much more powerful, I want to control at least 1000 leds in real time. Is it possible to use monitor electronics to control leds or decode signal direct from graphic card to control leds? Levels of gray don't interest me at this moment, only On/Off and big number of leds. Is there anone who can help?

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Joined: Jan 28 2005
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no. this is the holy grail ti

no. this is the holy grail times ten. it is possible to use leds as a 2D display. just not with standard graphics card.

chris501's picture
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Joined: Apr 5 2005
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i'm interested in how you did...

...the thing with 256 leds. i once developed a version using an atmel controller, but that was not real time, it used stored patterns in the RAM and just did a switch between different patterns when you've hit the button on the back of the pc.

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Joined: Oct 10 2005
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Do you have an idea where I c

Do you have an idea where I can find graphics card for led control?

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Joined: Oct 10 2005
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More details about electronic

More details about electronics that I used to control 256 leds you can find on the site http://www.protee.org/en/products/nogo.html This is really powerful card but we didn't find solution to control more than 256 leds. I used this card to show pointilised image directly from camera. I used director as applicaion and serial port for talking with card. Do you still have yours? How many leds you can control?

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PIC?

I've seen various projects that use the PIC microcontroller to output an image to a monitor or TV, so it would seem like they have the speed necessary to do this. At least one of them used the TV's sync pulse as the clock for the PIC, keeping the two perfectly synchronised.

So in theory it might be possible to use one of the digital inputs on a PIC, AVR or some other fast µC to read a pulse on one line of a VGA output, and use a -lot- of multiplexing to drive large numbers of LEDS from the digital outs. I'm assuming you'd set the computer to 640x480, monochrome (1-bit colour).

Processor speed aside, you'd want to look at the response times of the input pin, and of whatever you're using for multiplexing.

You might get some ideas about multiplexing by looking at the DOUTX4 module from the MIDIBox Hardware Platform. Or not.

If you can matrix the control lines on the LEDs, you'll only need 640 + 480 outputs, not 640 x 480. Either way, you're looking at endless hours of soldering. Using one of the very old Macs that outputs less than VGA might be an idea.

This is about as crazy as my idea of interfacing a GLCD to a Mac Plus.

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chris501's picture
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Joined: Apr 5 2005
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in some way.

ah, yes. in some way, i still got it... Wink everything is disassembled and stuffed in a box somewhere in the cellar. hmm... maybe time has come to resurrect that project!

i just used it in my old pc, it was hooked up to a switch on the front panel. with that i could swap through 4 different patterns for my led "display". it consisted of 48 led's mounted on the side of the case. however, i don't have any idea how to control more than 256 led's. not yet.

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Joined: Oct 10 2005
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1000 led display

Hello again thanks for interesting in this subject it becames more and more interesting. I found one project on the net on http://www.hackaday.com/entry/1234000457021144/
Guy made an 3D display with 1000 leds, i sent him e-mail with question what he was using as electronics. I'll send you answer... if i get it.

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Joined: Oct 10 2005
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well he didn't tell me what k

well he didn't tell me what kind of electronics was used

chris501's picture
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Joined: Apr 5 2005
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what a pity.

i was really curious about the method he used to display videos on it Wink
however, please keep us informed if you get any news on that topic.

how far did you get with your considerations?

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I remember seeing aproject a

I remember seeing aproject a few years back by I believe a college that uses i -think- over 1 million LEDs and fiber optics to create a display that was about 6 feet. I believe it was the highest resolution display ever made at the time. Wish i could remember who did it.