LED's in your video

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socrates
Posts: 1
Joined: Tue Oct 14, 2008 5:50 am

LED's in your video

Post by socrates » Tue Oct 14, 2008 5:58 am

Hi

I saw your video about the 8x8 LED. In the desrciption of the video stands that you use high brightness LED's. Do you know how much mcd (milli candela) they are?

paul
Site Admin
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Joined: Mon May 12, 2008 4:19 pm

Re: LED's in your video

Post by paul » Sat Oct 18, 2008 3:25 pm

Sorry about the slow response,
I've been busy. I need to find the setting that will send me mail when something new show up in the forum. Maybe this will spur me on.

the world's full of LED's. I've been trying to just get them at Digikey recently. There are definitely high quality Asian ones out there but there are also lots of pitfalls, like fake specs, long delivery times and high shipping costs.

LED's are kind of like flood lights or spot lights. There is an angle in the rating where the brightness falls off to half brightness. The narrow beam LED's are going to have higher mcd ratings but you have to be looking directly down the barrel of the LED. Good for traffic lights proabably but not so great for most things like signs.

Best bet it to buy a few LED's and test them before proceeding. I engineered a big LED sign job and we tested panels of about 4 LED's before deciding on the ones we used.

Paul

Severian
Posts: 14
Joined: Thu May 22, 2008 5:48 pm
Location: Texas

Re: LED's in your video

Post by Severian » Thu Apr 23, 2009 1:42 am

Paul,
Which LED did you choose? I'd like to at least look it up, and maybe I would get a few.
Good day

paul
Site Admin
Posts: 735
Joined: Mon May 12, 2008 4:19 pm

Re: LED's in your video

Post by paul » Thu Apr 23, 2009 9:36 pm

If you want blue 5mm LED's - this series 516-1695-ND is bright and beautiful. I paid around .50 each when I bought them for a big sign project a few years back but they seem to be more expensive now.

I hate to admit this but my record keeping isn't that great on prototype / one off projects. So that particular LED part number in the video is lost to history I believe.

I keep good records on the production stuff though but haven't bought any LED's for kits except generic ones I buy for pilot lights. Here are a few remarks on LED's.


Paul

dataman
Posts: 13
Joined: Fri Sep 04, 2009 1:12 pm

Re: LED's in your video

Post by dataman » Fri Sep 25, 2009 5:48 pm

When I chose LEDs for my build,
I chose something I knew the vendor would be stocking for a while.
As I was sure I'd be making several purchases.
Well, I started with 200, ramped up to 500,
Now I'm ordering by the 1,000.

I chose 697522 from JameCo,
About 9 cents per 100, or 7 cents per 1000.
Had a good combination of high viewing angle: 50 degerees
And high wavelength: 635
MCD was about: 19

But man, in a dark room, these are bright enough.
I swear I've been sunburned by some of the displays.

Doing the math, for maximum output I should be using 470 ohm resistors,
But I like using the 1k ohm resistors as my LEDs are going to need to last a long time.
You really can't maintain these panels once you solder in, so think long life.

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