Large LED display?

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    Boris Mohar

Forget that! Look at this site:

It is hugh displays using a single line of led's on a spinning arm. Makes full color video..

schreef in bericht news: snipped-for-privacy@e3g2000cwe.googlegroups.com...

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

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:

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

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.

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Paul Hovnanian     mailto:Paul@Hovnanian.com
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There was a man who entered a local paper's pun contest. He sent in ten
different puns, in the hope that at least one of them would win.
Unfortunately, no pun in ten did.

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

Tam

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.

--
When you hear the toilet flush, and hear the words "uh oh", it's already
too late.    - by anonymous Mother in Austin, TX
Spam block in place, no emil reply is expected at all.

and may well use just as much power as having individual LEDs (to get the same brightness).

On 06/10/2006 the venerable snipped-for-privacy@yahoo.com etched in runes:

Have a look here:

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

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John B

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

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