Giant LED Displays - Re: Motion video on an IBM PC/XT - Methodology

[Allison]

>
>Subject: Giant LED Displays - Re: Motion video on an IBM PC/XT - Methodology
>   From: Grant Stockly <grant at stockly.com>
>   Date: Mon, 14 May 2007 21:53:37 -0800
>     To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>
>At 07:40 PM 5/13/2007, you wrote:
>>About 3 years ago I announced to the list a little something I'd done with 
>>an IBM PC/XT with CGA that was unconventional for the platform 
>>(full-motion video using stock hardware).  I recently gave a talk at a 
>>hacker convention on the complete methodology of how I did it, and the 
>>video of that talk is now available here:
>>
>>http://www.archive.org/details/8088CorruptionExplained
>
>This whole discussion has reminded me of an unfinished project of mine, a 
>192x99, 19,008 pixel LED display.  I have not manufactured the driver 
>circuits, but they have been designed.
>
>The display is organized/refreshed as 11x1728.  8x11 characters look very 
>good to me, so I designed it to handle 24 wide by 9 high characters.
>
>Here are pictures of it:
>Front:  http://www.stockly.com/images2/060129-LED_Display_Front_2718.jpg
>Back:  http://www.stockly.com/images2/060129-LED_Display_Back_2716.jpg
>Weight of all the 
>legs:  http://www.stockly.com/images2/060129-Weight_of_39584_Legs_2696.jpg
>
>As you can see from the pictures it is as big as a couch.  : )
>
>I built it in the spirit of blinkin lights for my Altair.  19008 LEDs is 
>2376 bytes, 71280 bytes a second at 30 frames.  The altair should be able 
>to handle this...???  Any ideas?

Thats faster than SD 8" FDC data rate!  Thats pushing an 8080 hard.

>I would really love if it could handle a shade or two of grey.  : )  I'm 
>considering now building a driver out of an FPGA.  It would be able to 
>handle a fast refresh rate and frame rate in order to get grey scales.  I 
>was thinking 4 shades would be enough.  The FPGA might even be able to act 
>as the dual port SRAM for the bitmap display?  Any ideas how I should 
>proceed?  : )

You want the CPU doing as little as possible.  If at all possible the 
display is refreshed by DMA from local or other memory and the CPU is 
there to update/alter the display.

>You can find my thread on this on USENET called "Wall of RAM".  I have 
>copied it here:
>http://www.stockly.com/forums/showthread.php?t=21
>
>Grant 

;) if I were to do something on that grand a scale I'd consider a LED 
billboard of VDM-1 (160x512) (roughly 30"x100"). Of course it would 
have to use green leds.


Allison