Another Led sign design!

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Ali_dehbidi
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Posted by Ali_dehbidi: Fri. Dec 11, 2009 - 10:30 AM
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Hi
I want to use spartan 3AN devices to build a led sign. I have a question. can i use the fpga ports to derive the leds directly.i want to turn 128 leds on with 128 outputs of the device simultaneously each capable of driving 24ma to each led. is that possible? is there any limitations
thanks for you replies.

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TPE
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Posted by TPE: Fri. Dec 11, 2009 - 11:13 AM
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Read the datasheet? but 128 led @ 24mA --> 3A
I will be impress if a fpga can to it!

Thierry Pottier

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leon_heller
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Posted by leon_heller: Fri. Dec 11, 2009 - 11:14 AM
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You will be better off using XMOS devices:

http://www.xmos.com

It's one of the applications they were designed for. Plenty of design assistance is available. They are a very nice company to work with, here is their new developers' forum:

http://www.xcore.com/

They also have a conventional forum:

http://www.xmoslinkers.org

Leon Heller G1HSM

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Ali_dehbidi
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Posted by Ali_dehbidi: Sat. Dec 12, 2009 - 05:43 AM
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Ok maybe by using some buffers like 74xx can solve the problem.
here is the second question?
there are kinds of led signs in our town that they have only single color brightness. they do not use pwm or anything similar to change the brightness of the leds but they have very interesting effects on them they look like they have created something with flash but in single color format!
I want to know is there a software that can build animations with text and produce an uncompressed avi so maybe we can benefit from it's outpout and build a led sign to just play the file.
any ideas are welcome!

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jayjay1974
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Posted by jayjay1974: Sat. Dec 12, 2009 - 02:24 PM
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Usually LED signs use multiplexing. What kind of LED sign do you mean? The scrolling message sign type or the neon-like fixed stuff that say 'OPEN' and the like?

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daqq
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Posted by daqq: Sat. Dec 12, 2009 - 02:27 PM
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http://www.austriamicrosystems.com/ have a lot of nice ICs for LED driving.

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jayjay1974
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Posted by jayjay1974: Sat. Dec 12, 2009 - 02:36 PM
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I have a (broken) LED message sign that uses plain '273s and ULN2003s to drive a 80x7 matrix with a Intel 8039.

The MCU is dead I think, so still looking for a new one.

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leon_heller
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Posted by leon_heller: Sat. Dec 12, 2009 - 02:41 PM
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XMOS uses the Macroblock MBI5026 for driving their LED arrays:

http://www.mblock.com.tw/

Leon Heller G1HSM

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Ali_dehbidi
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Posted by Ali_dehbidi: Sun. Dec 13, 2009 - 12:50 PM
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Quote:
Usually LED signs use multiplexing. What kind of LED sign do you mean? The scrolling message sign type or the neon-like fixed stuff that say 'OPEN' and the like?

I mean the scrolling one! did you see them! they are just great and i think they make an avi file and extract the pixel data and just play the pixle data with avr. maybe something like swish can make the animation.
do you have seen anything similar or do you know any good software.

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jayjay1974
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Posted by jayjay1974: Sun. Dec 13, 2009 - 02:37 PM
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The normal scrolling ones do not play an AVI file :) They generate the pixeldata on the fly from text you have entered. Quite easy to do really, at most a few hundreds lines of C if you want basic scrolling only.

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Ali_dehbidi
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Posted by Ali_dehbidi: Mon. Dec 14, 2009 - 05:38 AM
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Quote:
The normal scrolling ones do not play an AVI file They generate the pixeldata on the fly from text you have entered. Quite easy to do really, at most a few hundreds lines of C if you want basic scrolling only.

I have done a led sign project in past and i was doing almost the same way.I was generating simple scorolling effect on the flay aside some other simple animations.but the point is these new led signs that i have seen have very nice effects that i'm sure it's imposible to do with the speed of avr8.but i still think they have used avr for these led signs too! I think the main task of avr is to display precompiled animation with pc on leds! I think they let the hard task for pc and after that just generate the pixle data and the avr now have a simple task and that is showing that data!

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jayjay1974
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Posted by jayjay1974: Mon. Dec 14, 2009 - 07:02 AM
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What kind of effects?

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Ali_dehbidi
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Posted by Ali_dehbidi: Mon. Dec 14, 2009 - 08:10 AM
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Have you seen flash software! or swishmax. they produce effects like bouncing letters or rotating and rippling water letters.zooming in and out! and more!

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cheng_bei
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Posted by cheng_bei: Mon. Dec 14, 2009 - 01:43 PM
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The idea is very good. I have to learn more.

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Ali_dehbidi
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Posted by Ali_dehbidi: Tue. Dec 15, 2009 - 05:47 AM
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Hi cheng_bei
Can you name some good part suppliers in china.I mean i want to buy things cheaper than other places.and also if you know some pcb house with reasonable prices and good quality it would be appreciated.

thanks in advance.

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cheng_bei
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Posted by cheng_bei: Tue. Dec 15, 2009 - 08:23 AM
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I am sorry I am just a student. I didn't very know about the market business.

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