Large LED display?

Question

Hi all,Has anybody here ever tried to create a large displayusing just LEDs, like a 640x480 display for eventualuse with a computer after control logic is added?I know, skeptics will say that's too much solderingto do, and then control logic wouldn't be compatiblewith any existing video circuitry, but then againindividual LEDs nearly last forever and if multicolor LEDsare 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 themand most people these including myself preferat least 800x600 for 480,000 total.Thanks.

Boris Mohar · Accepted Answer

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James Thompson · Answer

Forget that!  Look at this site:  is hugh displays using a single line of led's on a spinning arm. Makes full color video..

petrus bitbyter · Answer

schreef in bericht news: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 · Answer

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:

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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. · Answer

Those are neat. But I think a better approach would be to have a fixedstrip of LEDs and scan the image using a rotating mirror and optics tomake a projection system. The size of spinning arm displays is limitedby the arm length and swing radius. And you don't have to figure out howto upload image data to a spinning arm.-- Paul Hovnanian     mailto:------------------------------------------------------------------There was a man who entered a local paper's pun contest. He sent in tendifferent puns, in the hope that at least one of them would win.Unfortunately, no pun in ten did.

Tam/WB2TT · Answer

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

Impmon · Answer

LED adds up.  Each single color LED is about 20mA.  Toss in 138,240LEDs for a smaller display, tri color element taking probably over60mA and that easy gets over 8 amps top.LED are great for outdoor display and other major area like sportsstadium.  But defiantly not for in home use.-- When you hear the toilet flush, and hear the words "uh oh", it's alreadytoo late.    - by anonymous Mother in Austin, TXSpam block in place, no emil reply is expected at all.

CWatters · Answer

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

John B · Answer

On 06/10/2006 the venerable  etched in runes:Have a look here:  and click on "Chain Reaction". There's some of my work buried inside it.-- John B

Tam/WB2TT · Answer

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

skenn_ie · Answer

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

Large LED display?

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