Wall of RAM

If they ain't BLUE LED's then don't bother, any other colour will look lame! :->

Dave :)

I'm picturing a '70s scifi where they had an extra large green CRT, complete with burnin :-) If you put in a PCM driver to control intensity, you can do some truely interesting effects. Think plasma.

...

Too much time on your hands, and _WAY_ too much money! ;-P

Cheers! Rich

You could sell them on ebay.

one of the X windows screen savers emulates pong on a TV complete with low level snow, slow phosphor, gaps between the scan lines and loss of sync near the bottom, of the screen.

:)

Bye. Jasen

Here is an update:

PCB Top:

I should have made the power traces bigger, oh well...

Here are some friends I convinced to help me:

We put the couch on spacers, put a table in front of it, and watched SciFi Friday...

Here is 1 of the 18 required panels, finished. :) 990 LEDs!

Crikey, you are serious! One of those competely pointless but fun projects - love it! Gotta see photos of the final thing, keep us updated!

Dave :)

I just checked my KDE screensavers, and DEWD! There sure are some kewl ones!

Cheers! Rich

Well, its been 8 days since I started soldering.

I'll post some pictures in the morning. :) Now I'm off to comp.arch.fpga for advice on this application. :)

I felt it was a mile stone if anything. If all goes well on Sunday I'll have another 2970 down which will push me past the half way mark. Then I'll feel better. Right now this thing is taking a long time. My average is about 4 hours for each board of 990.

I bought brand new spools of solder in the beginning and I'm keeping ALL of the cut off legs. Should make for some interesting statistics! :D

Just thought I'd give an update:

-I've soldered 13,200+/-10 LEDs so far.

-Of the 16oz of solder I started with only 7.25oz is left. My food scale isn't strong enough to weigh the cut off legs. My friend says he has a digital one, so I'll try to get that.

-Only 5808 LEDs left. I have to finish this project by the 28th in order to save face to a friend I made a bet with. ;)

Keep pulling for me! I designed the column drivers. Looks like that will be a project too. Column Driver for 216 characters:

-54 - 74HC04

-27 - 74HC138

-27 - 74HC133

-27 - 74HC244

-432 - 74HC574

-216 - ULN2803

-1728 - 24ohm resistor

-etc

This is one build, thats for sure. Preliminary calculations are showing 138.7A draw, 276watts of heat and 416watts of stuff other than heat. Should be bright enough. :)

Holy LED display Batman! Keep it up, we want lots of progress photos and of the final thing!

Has anyone else ever done an individual project of this scale before?

Dave :)

I was soldering the 14th board on Tuesday. After a little over 600 LEDs I found that they were ALL in backwards!!!! : ( I don't have any spare boars. At least 300 of the LEDs will need to be desoldered (but I have a nice station so it shouldn't take too long). Its easier than it sounds since I spray painted the boards black. Once I "think" I have the board orientation right I was just blindly pushing them in. Soldering 10,000 LEDs at 1000 a day tends to do that to you. ;)

At this point I am VERY sick of the 20k LED project. So I decide to visually (lighting the LEDs) test the 13 completed boards of 990.

I found one other board where I did 32 rows of 30 correctly and put one row of 30 in backwards.

The other most common defect was soldering one pin and not soldering the other.

I found that most of my brother's solder joints were cold, so I went ahead and reflowed about 3 boards of 990 just to be safe even before I did a test lighting.

If I solder one board Thursday and one board Friday I will have 3 boards for Saturday. At peak efficiency it will take 12 hours of solid soldring to do 3 boards of 990. I have to get them done by the 28th to win that bet. ; )

My next project is to make a set of PCBs for the Magic-1 TTL computer. I think that even better than an Altair driving the display would be a TTL computer. :)

The Hako desoldering iron works great. Took me about 35-40 minutes to desolder 300LEDs. Why can't they go in that fast? : ( The whole kit with extra tips cost me about $280. I never would have bought it without a strong recomendation from a friend. It works much better than I thought it would.

OK, what's a "Magic-1"? Oh, wait a sec - google is our friend.... "Your search - "magic-1 ttl computer" - did not match any documents."

When I think "TTL Computer", I think DEC PDP-11, National IMP-16, and Control Data Enhanced Normandale Controller/Tester. :-)

They all used 74181's. I also used to read the AMD AM2901 bit-slice manuals and app notes, but I don't know if those things can even be had in this century. )-;

(I'm sure the whole thing could be done in a CPLD, but what's the fun in that? ;-) )

Good Luck! Rich

Are you sure? I had documents:

Here is his link:

If you think my project is crazy, take a look at all of his wire wrap connections. :)

I finished soldering all the LEDs on Saturday and spent Sunday mounting all the boards. Pictures of the size of this thing at the bottom!

All 19008 LEDs have been tested. Not a single LED was bad.

Here is a picture and weight of 39584 LED legs: (yes, I saved them for the purpose of weighing them. ;) )

Here is the display from the front:

and back:

I have to admit, its huge. It wasn't so big in the drafting program on my computer screen! Even I only discovered how big it was after all the LEDs were soldered and I was placing them on the table for drilling. WOW...

They're attached to an 81x34.5 piece of 1/4" plexiglass.

So, did you think this was really going to happen? ;)

Frigg'n brilliant Grant! My propeller hat is off to you!

When can we see it actually lit up and playing PONG?

Dave :)

Does a magnet do anything to them? If not you could send them to me and I could melt them down and cast some interesting object worthy of adorning such an array :-)

Tim

-- Deep Fryer: a very philosophical monk. Website:

Most LED leads are tinned steel.

JazzMan