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Thread: LED lumias

  1. #1
    Join Date
    Jan 2008
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    Stockholm, Sweden
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    799

    Default LED lumias

    Since lumias seem to be the latest craze I feel the urge to bring up the question if you can use LEDs instead of lasers with lumias. It seems like a much cheaper solution, especially for those very welcome blue colors. You can get pretty narrow beams with LEDs, especially if you use optics.

    I built this simple lumia-like LED contraption:
    http://www.youtube.com/watch?v=PTKiEO8uTYc
    http://tocket.mine.nu/albumtest/temp...lbumtest%2fled

    It uses 11 1W LEDs, 5 red, 3 green and 3 blue that are controlled by PWM. On top of them is a glass bowl, like this:


    Rotating or slowly moving the bowl creates a very nice effect, but it is rather heavy.

    Has anyone else built LED lumias before? Do you think it's a good idea?

    Oh, here's an interesting effect of PWM with my camera that I noticed.
    http://www.youtube.com/watch?v=YgrUZHSN9NE
    You can really see the pulse width in an almost matrix-like effect. I have seen this phenomenon with my camera before, recording some explosions , but never been able to fully explain it. Why do CCDs do that?

    Here's the brain in my next LED project in progress by the way:

    An Arduino microcontroller. These things are wonderfully easy to use. It took me about 30 minutes to make an IR remote controlled RGB color mixer using it. I've never programmed for anything but my computer before and I'm not particularly good at electronics either.

    As for the project... Well, 5 3W RGB LEDs are on their way to me from china now. They will be powered by 3 TLC5940 LED drivers, receiving their instructions from the Arduino. This will then all be put inside of an IKEA lamp, like this:

    Should make a nice moodlight. Perhaps even with some lumia effects in it...

  2. #2
    Join Date
    Sep 2007
    Location
    Omaha, NE
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    769

    Default

    That's a great project- thanks for sharing the details!
    I have a Laser Stars projector and it makes a really nice blue glowing nebula effect, so yes- I think LED's are a very viable option.
    -Mike
    Attached Thumbnails Attached Thumbnails laser-stars-projector-2.jpg  



  3. #3
    Join Date
    Mar 2006
    Location
    Massachusetts
    Posts
    194

    Default BlinkM

    Hey check out... http://www.sparkfun.com/commerce/pro...oducts_id=8579

    I have a few in random projects.
    Excited Photons Burned my Signature

  4. #4
    Join Date
    Jan 2008
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    Stockholm, Sweden
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    Default

    I have looked at those before, but they seem rather expensive. I got the 3W RGB LEDs for $5 each and I suspect they are far more powerful than a BlinkM (350 vs 20 mA per color). The BlinkM seems to be very well documented and capable though, which is always nice. However, so is the TLC5940 (albeit the documentation is far more technical). A TLC5940 has 16 constant current PWM outputs, each capable of sinking 120 mA. I got them for free, but they're quite cheap to buy as well.

    I want to make a high brightness moodlight, and I suspect it will indeed be quite powerful.

  5. #5
    Join Date
    Mar 2006
    Location
    Massachusetts
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    194

    Default

    I made one of these once. It powers my Fiber optic star ceiling over my bed

    http://picprojects.org.uk/projects/b...trgb/index.htm
    Excited Photons Burned my Signature

  6. #6
    Join Date
    Jan 2008
    Location
    Stockholm, Sweden
    Posts
    799

    Default

    Hmm... I think I need to get myself some logic level MOSFETs. That driver seems very simple; I thought more would be needed to properly drive MOSFETs. To think one of those little buggers can switch 30A...

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