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PJ Allen
07-15-2007, 09:21 AM
ˇ Here's a 5x7 dot-matrix demonstrator that Iˇbased on anˇSX28.
The 5x7 is "super" because it's 3 x 4.25 inches.ˇ Each "pixel" has a VF of 6.5V or so.
ˇ Here's a YouTube link, to see it in action -- http://www.youtube.com/watch?v=aV0P_2FFLUM (http://www.youtube.com/watch?v=aV0P_2FFLUM)

ˇ Attached are the schematics,ˇa picture of the "main board", and a couple of programs.ˇ One program is that used in the YouTube and the other is just of the "swimmer" going up and down (trapped forever, poor creature.)ˇ So, you can see my approach to interfacing with higher voltages, rendering letters and numbers, and doing animation.

ˇ Fellow members, the programs, schematics, and everything presented hereˇare for your enjoyment, that is, your personal, private use only; publication and commercial use are expressly prohibited.

ˇ Update -- Though not shown in the schematic, U1 & U2 (the LM339s) are supplied by the +9V (the 7809 output.)
ˇ Another Update --ˇAll of the 2K2 resistors should be pulled up to +9V.ˇ I made the correction in the page1 (_p1) Schematic.
ˇ Post Edit -- 22FEB2009ˇ I devised another animation (set of patterns) and uploaded it to youtube. (http://www.youtube.com/watch?v=QglgjVDvgjU)


Post Edited (PJ Allen) : 2/23/2009 2:25:32 AM GMT

Professorwiz
07-16-2007, 07:56 PM
Very cool! Where did you get the cool LED display from?

PJ Allen
07-16-2007, 10:32 PM
Got a bunch from Electronic Goldmine a few years ago, figured I ought to get around to using 'em.

Update -- adding a pic of the SX-board which I wasn't able to include previously.

Post Edited (PJ Allen) : 7/16/2007 2:48:07 PM GMT

Forrest
07-17-2007, 12:37 AM
Here's a similar looking display - 8 x 8 that measures 2 x 2 inches for $29.95 www.sparkfun.com/commerce/product_info.php?products_id=683# (http://www.sparkfun.com/commerce/product_info.php?products_id=683#)

Loopy Byteloose
10-01-2007, 02:17 AM
The reason that is $29.95 is that it is 3 colors. This project uses only one color. You can do much better on price for a one color display.

Also, having a 3 color 8X8 swimmer would have to more than triple the control circuitry and code would be more complex. You would likely need and SX48 in order to have enough I/O pins.ˇ Getting exactly the right colors might drive you nuts.

In other words, you would hugely expand the scope of the project.

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"Everything in the world is purchased by labour; and our passions are the only causes of labor." -- DavidˇHume (1711-76)ˇˇˇˇˇˇˇˇ


ˇˇˇˇˇˇˇˇˇˇˇˇˇˇˇˇˇˇˇˇ Tropically,ˇˇˇˇˇ G. Herzog [ˇ黃鶴 ]ˇin Taiwan


Post Edited (Kramer) : 9/30/2007 6:24:39 PM GMT

Loopy Byteloose
10-01-2007, 03:19 PM
This is an after thought,
The 3 color 8X8 matrix is more complex because usually the user wants to use all the LEDs to mix colors.

If you really want to try to do so, the Propeller is ideally suitable. Each color takes 8 bits of ROWdata that could be generated by an independent COG. The 8 columbs can be provided by a serial to parallel shift register.

The importantant thing is that you have parallel processing available. That allows you to enable mix colors. At first you might find it a limited pallet, but with each color having an independent processor, you might be able to fool with timing to widen the range of colors.

As you can see, it would likely take 3 SXes that were working in synch. So you really should consider a Propeller to make that $29.95 display worthwhile.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"Everything in the world is purchased by labour; and our passions are the only causes of labor." -- DavidˇHume (1711-76)ˇˇˇˇˇˇˇˇ


ˇˇˇˇˇˇˇˇˇˇˇˇˇˇˇˇˇˇˇˇ Tropically,ˇˇˇˇˇ G. Herzog [ˇ黃鶴 ]ˇin Taiwan