Multi-stage LED light project

Discussion in 'The Projects Forum' started by Leviathan, Aug 1, 2012.

  1. Leviathan

    Thread Starter New Member

    Aug 1, 2012
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    Hi all :)

    Intro
    I've got a bit of a project that I'm looking at, but my electronics knowledge is far from brilliant. I can follow a circuit diagram and such but when it comes to things like figuring out what sized battery, what kind of resistors I need, most efficient setup etc I haven't got a clue (I can practically see your eyes rolling at this point ;) ).
    So I figured I'd ask some help from people with a bit more idea what they're doing than me.


    The Project
    What I've got is a hollow, semi-pliable ball about 20cm across made of.. well, honestly I don't know. It's some kind of frosted plastic or rubber that is ludicrously tough.
    This has been adapted to sit on the end of a staff, and the idea is I want it to provide light, a bit like a cross between a lamp post and a wizard's staff (previously I've just put a bike light into it and that works, but I want it to be *awesome*, not just 'work').

    The Essential bits
    1) It needs to give off a decent amount of light
    2) It needs a standard on-off switch that I can feed through a hole to the outside of the globe
    3) As the staff is detachable, it needs to somehow hold itself in place inside the ball
    4) The light should be unidirectional

    The Extra bits
    1) Ideally I'd like two sets of lights, a 'dim' and 'bright' option
    2) Even better would be another set of lights in green/purple to make an "Eye of Sauron" like effect on one part of the globe, just for laughs.


    Ideas so far
    I figure that one way of doing it will be to simply have three switches and three circuits running through it, one "Eye of Sauron" of coloured LEDs, one circuit of "Bright" ones and one circuit of "Warm" ones.

    Relatively simple, but not especially efficient, especially since it'd probably involve three sets of batteries I'd assume.

    Information/Advice Required
    1) Is there a more efficient way of doing this than three separate circuits?
    2) Any advice on battery to use, resistors, circuit, LEDs, etc?


    Sorry this is all so vague, that's the issue with not entirely knowing what you're asking for I guess :)
     
  2. #12

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  3. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Might start by trying a single bright [10,000mc] LED to judge visibility and coverage. A bike light might give 240 deg coverage & LED 30 deg.
    How large of an opening in the ball is there?
    Is the staff hollow?
     
  4. KJ6EAD

    Senior Member

    Apr 30, 2011
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    Did you mean omnidirectional when you said unidirectional? Is the ball rigid or flexible?
     
  5. Leviathan

    Thread Starter New Member

    Aug 1, 2012
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    Thanks, I'll take a squiz through there once I'm able to sit and digest it all :)


    That'd be a good first step! Thanks
    The opening in the bottom of the ball is pretty much what I've (with difficulty) hacked out of it, so it's very rough. It's completely hollow but the actual opening is.. maybe 10cm across.
    The staff is solid, but only protrudes about an inch into the ball (the top of the staff is about 10cm across, then an inch down is a 'collar' that's wider, so it stops there)


    Bah, stupid autospelling, I thought that was turned off. Yep, omnidirectional.
    As to the ball.. depends on how you define flexible really. I'd put it at slightly more pliable than a tennis ball.
     
  6. wayneh

    Expert

    Sep 9, 2010
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    The circuits you need are quite simple, but the problem is to define the exact lights you want to use, in particular their power requirements. The circuits will be designed to support those lights, so you really need to know what is needed. Of course the circuit can have flexibility to allow experiments.

    Do you really need omnidirectional (in 3 dimensions), or would horizontal be better? I'm thinking of LED streetlights. They shine a very bright LED straight up onto a cone-shaped reflector that directs most of the light horizontally. Your sphere sounds like it's a diffuser on its own. Do you need even illumination inside of it? Do you want to provide enough light to walk around safely in the dark, or be seen in daylight, or would merely being seen in the dark be enough? These extremes cover a wide range of power.
     
  7. Bernard

    AAC Fanatic!

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    10 cm?, that is about 4 in-- one heck of a staff.
     
  8. Leviathan

    Thread Starter New Member

    Aug 1, 2012
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    So my ideal plan is to grab some LEDs, test their light output, and go "Right, I have X number of Y output LEDs, can someone help me build the circuit?"

    I'm looking for (when in 'bright' mode) enough light to see my way in the dark. The 'warm' mode would be more like "Can see faces at two feet" kind of thing.
    Visible in daylight isn't a requirement.

    When I had the torch in there, some light is definitely diffused, though obviously the front cone is still stronger. A horizontal ring of LEDs may well work, possibly with a few pointing upwards if I feel the need to wrangle that.

    Hrm. You're probably right on that. I'll take some actual measurements and pictures of the setup tonight so that it's easier to see.
    I think I'm confusing the two holes in the bottom.
     
  9. Leviathan

    Thread Starter New Member

    Aug 1, 2012
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    Okay, it's actually 4-5cm across at the top of the staff, so that's roughly the size of the opening in the ball.

    Unfortunately the friend who currently has the ball forgot it on Friday, so I won't have pictures until the weekend.
     
  10. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Where did 4in come from?? more like 2 in, which might mean that you could mount a small ball, copper would be nice, on end of staff with surface mt LEDs spaced around it. If staff were hollow, all electronics & batteries could be placed inside. A possible LED is warm white, 90 lumen, 3.6V, 350mA, 140 deg, SM, @ $ 1.29, from Electronic Goldmine USA; total of 9 should give good coverage. Another one 4 pin semi SM, piranah, 3.4V, 100 mA, 40 deg ??, about 21 for full coverage, $1.15 @ All Electronics; I believe one I have is identical and is really bright @ 86 mA.
     
    Last edited: Aug 7, 2012
  11. wayneh

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    Sep 9, 2010
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    If you google "12v LED lightbulb" you'll find a number of things like this one. Might be perfect for this application.
    [​IMG]
     
  12. #12

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    Nov 30, 2010
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    Wayneh: Congrats on 3000 posts.

    (strantor said that to me so I'm just passing it on.)
     
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