Large LED display?

[[email protected]]

Hi all,

Has anybody here ever tried to create a large display
using just LEDs, like a 640x480 display for eventual
use with a computer after control logic is added?

I know, skeptics will say that's too much soldering
to do, and then control logic wouldn't be compatible
with any existing video circuitry, but then again
individual LEDs nearly last forever and if multicolor LEDs
are used it could be pretty pleasant to look at.

The key would be finding a cheap source of LEDs,
since even a 640x480 display needs 307,200 of them
and most people these including myself prefer
at least 800x600 for 480,000 total.

Thanks.

 

[Boris Mohar]

Hi all,

Has anybody here ever tried to create a large display
using just LEDs, like a 640x480 display for eventual
use with a computer after control logic is added?

I know, skeptics will say that's too much soldering
to do, and then control logic wouldn't be compatible
with any existing video circuitry, but then again
individual LEDs nearly last forever and if multicolor LEDs
are used it could be pretty pleasant to look at.

The key would be finding a cheap source of LEDs,
since even a 640x480 display needs 307,200 of them
and most people these including myself prefer
at least 800x600 for 480,000 total.

Thanks.

http://www.scoreboards.net/video_indoor.htm

 

[James Thompson]

Hi all,

Has anybody here ever tried to create a large display
using just LEDs, like a 640x480 display for eventual
use with a computer after control logic is added?

I know, skeptics will say that's too much soldering
to do, and then control logic wouldn't be compatible
with any existing video circuitry, but then again
individual LEDs nearly last forever and if multicolor LEDs
are used it could be pretty pleasant to look at.

The key would be finding a cheap source of LEDs,
since even a 640x480 display needs 307,200 of them
and most people these including myself prefer
at least 800x600 for 480,000 total.

Thanks.

Forget that! Look at this site:
http://hackedgadgets.com/2006/06/13/top-5-spinning-led-displays/
It is hugh displays using a single line of led's on a spinning arm. Makes
full color video..

 

[petrus bitbyter]

Hi all,

Has anybody here ever tried to create a large display
using just LEDs, like a 640x480 display for eventual
use with a computer after control logic is added?

I know, skeptics will say that's too much soldering
to do, and then control logic wouldn't be compatible
with any existing video circuitry, but then again
individual LEDs nearly last forever and if multicolor LEDs
are used it could be pretty pleasant to look at.

The key would be finding a cheap source of LEDs,
since even a 640x480 display needs 307,200 of them
and most people these including myself prefer
at least 800x600 for 480,000 total.

Thanks.

The largest one I ever played with was a 640*200 CGA compatible display. Its
dimensions were roughly 4x1.4m and it was build up with 16x16 5mm LED tiles.
It was placed in the Congresgebouw at The Hague at the time. The LEDs were
bi-color types, red and green, but only red was ever used. Some simple calcs
learn that it contained 133120 LEDs. The thing was also pretty noisy as it
required a lot of cooling fans. These days you'd look for 3mm tricolor LEDs
in tiles of 32x32. So it can be done but I will not go for it (unless
someone's gonna pay me)

petrus bitbyter

 

[Jonathan Kirwan]

Hi all,

Has anybody here ever tried to create a large display
using just LEDs, like a 640x480 display for eventual
use with a computer after control logic is added?

I know, skeptics will say that's too much soldering
to do, and then control logic wouldn't be compatible
with any existing video circuitry, but then again
individual LEDs nearly last forever and if multicolor LEDs
are used it could be pretty pleasant to look at.

The key would be finding a cheap source of LEDs,
since even a 640x480 display needs 307,200 of them
and most people these including myself prefer
at least 800x600 for 480,000 total.

Thanks.

Here's a couple of LED array systems that are build for such purposes.
I worked on developing testing, binning, and color balance systems for
production runs of these:

http://users.easystreet.com/jkirwan/tricolor led array 01.jpg
http://users.easystreet.com/jkirwan/tricolor led array 02.jpg
http://users.easystreet.com/jkirwan/tricolor led zoom 01.jpg

These use three separate supplies for red, green, and blue, include
current DACs and support for PWM for intensity built into them. They
burn some power, so I included the backsides in the first picture so
you can see the method used as part of the heat sinking for them.

Jon

 

[Paul Hovnanian P.E.]

Forget that! Look at this site:
http://hackedgadgets.com/2006/06/13/top-5-spinning-led-displays/
It is hugh displays using a single line of led's on a spinning arm. Makes
full color video..

Those are neat. But I think a better approach would be to have a fixed
strip of LEDs and scan the image using a rotating mirror and optics to
make a projection system. The size of spinning arm displays is limited
by the arm length and swing radius. And you don't have to figure out how
to upload image data to a spinning arm.

 

[Tam/WB2TT]

http://www.scoreboards.net/video_indoor.htm

Did you notice the 6KW - 57 KW power requirement?

Tam

 

[Impmon]

Did you notice the 6KW - 57 KW power requirement?

LED adds up. Each single color LED is about 20mA. Toss in 138,240
LEDs for a smaller display, tri color element taking probably over
60mA and that easy gets over 8 amps top.

LED are great for outdoor display and other major area like sports
stadium. But defiantly not for in home use.

 

[John B]

Hi all,

Has anybody here ever tried to create a large display
using just LEDs, like a 640x480 display for eventual
use with a computer after control logic is added?

I know, skeptics will say that's too much soldering
to do, and then control logic wouldn't be compatible
with any existing video circuitry, but then again
individual LEDs nearly last forever and if multicolor LEDs
are used it could be pretty pleasant to look at.

The key would be finding a cheap source of LEDs,
since even a 640x480 display needs 307,200 of them
and most people these including myself prefer
at least 800x600 for 480,000 total.

Thanks.

Have a look here:

http://www.karllautman.com/recent.html#

and click on "Chain Reaction". There's some of my work buried inside it.

 

[Tam/WB2TT]

LED adds up. Each single color LED is about 20mA. Toss in 138,240
LEDs for a smaller display, tri color element taking probably over
60mA and that easy gets over 8 amps top.

How do you get that, 138000 x .06 = 8280 amps.

 

[skenn_ie]

Did you notice the 6KW - 57 KW power requirement?

Tam

You need it if you compete with the sun...even on a small scale !

 

[Rich Grise]

Those are neat. But I think a better approach would be to have a fixed
strip of LEDs and scan the image using a rotating mirror and optics to
make a projection system. The size of spinning arm displays is limited by
the arm length and swing radius. And you don't have to figure out how to
upload image data to a spinning arm.

Map your pixels to polar coordinates and just spin the arm in a circle,
like half of an airplane propellor.

Cheers!
Rich