Best type of LED's for outdoor light

Discussion in 'General Electronics Chat' started by denno, May 25, 2011.

  1. denno

    Thread Starter Active Member

    Jul 1, 2008
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    I'm looking to make a semi-outdoor light using LED's and an aluminium rod. They're going to be placed above a table tennis table so light output is important, as it will need to illuminate the ball so it's easily seen.

    I was wondering what the best type of LED's would be to use for this project. Cree would be ultimate, but I'm on a budget, and can't afford to sprout for multiple Cree LED's. Light dispersion angle is obviously a factor, so the using lots of normal 3mm/5mm/10mm one wouldn't really help, I don't think.

    I was thinking I could use some SMD LED's, and I've found reems of 5050 SMD LED's on eBay, however I have no idea what the output of this light would be like, or comparable too. The specs say 4000-5000mcd, but this number means nothing to me in comparative terms.
    There is also an option of using superflux LED's, but they didn't seem to have a very high MCD rating..

    Could anyone please help with a suggestion of the type of LED I could use? I haven't got any power specs yet, I was planning on buying a power supply once I've worked out how many LED's I'm using.

    Thanks in advance.

    Denno
     
  2. KJ6EAD

    Senior Member

    Apr 30, 2011
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    363
    You need the light to be diffuse so hanging above the table in a large panel or rectangular array would be appropriate. LEDs for illumination are usually rated in lumens as they should be. LEDs that are rated in millicandelas or candelas are more often intended for direct viewing or spot illumination. Try to come up with a lumen figure based on other lights you have and use that as a guide to how many LEDs you will need. Keep in mind that LEDs will dim some with use, especially the less reputable brands.
     
  3. denno

    Thread Starter Active Member

    Jul 1, 2008
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    Thanks for the reply KJ6EAD, I wasn't aware of the mcd/lumen rating as also hinting at their use. The only problem is, I see SMD LED's being used for house hold lights and car lights all the time.. I'm just wondering what type they are, and I'm not sure how to find out exactly.

    Would 5050 SMD LED's, arranged in a rectangular array, give off much light? If I use say 18 LED's, with each LED putting out ~5000 mcd, would this give much light?

    I've got one of these lights in my bedroom, but I don't know what type of LED's are use in it.
    http://www.ebay.com.au/itm/8W-166-l...hting_Fans&hash=item43a75382fd#ht_3495wt_1141

    Could you, or anyone else, help me out with this? These LED's appear to put out good light when put into an array light above.

    Thanks heaps

    Denno
     
  4. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
    363
    There's no way to say without knowing the viewing angle of the LED. That's part of the reason why the lumen is so much more useful.

    http://en.wikipedia.org/wiki/Lumen_(unit)
    http://en.wikipedia.org/wiki/Candela
    http://en.wikipedia.org/wiki/Lux

    You can get all manner of LED strips, etc. pre-built: http://www.superbrightleds.com/.
     
  5. denno

    Thread Starter Active Member

    Jul 1, 2008
    30
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    Ok so from following your wiki links and thinking I was onto something, I've now come to the conclusion that it's going to be near impossible to get some sort of numbers as to what the light output would be.

    So really I'm asking if anyone has experience in creating their own LED lights for illumination, and what they used etc?

    Thanks for your help KJ6EAD.

    Denno
     
  6. KJ6EAD

    Senior Member

    Apr 30, 2011
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    363
    There's one guy on this or another forum that's advocated buying cheap white Christmas lights and just adding strings until it's bright enough. If you get the icicle or net lights with white wires, you can pile them up in a diffusion housing such as a fluorescent tube ceiling box.
     
  7. denno

    Thread Starter Active Member

    Jul 1, 2008
    30
    0
    That's a decent idea.. I'll have to look into it.. I may very well just end up buying pre-made LED bars though.. Would really love to make my own, but maybe that can be a project for further down the road when I have a little more money to play with and can 'waste' it on finding out which LED best works..

    Thanks again for your help mate :).

    Denno
     
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