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Re: noob looking for circuit help

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  • wilf_nv
    Hi Chuck, The 240 pummer is not a good starting point for the kind of fade in, fade out function you are looking for. The 240 pummer LED current pulse and
    Message 1 of 3 , Nov 30, 2006
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      Hi Chuck,

      The 240 pummer is not a good starting point for the kind of "fade in,
      fade out" function you are looking for. The 240 pummer LED current
      pulse and light output has the inherently fast attack and slow decay
      of a charge pump circuit and there is not much you can do about it.

      However there are several circuits which would give the desired
      flowering light effect: The QLF, Nulite and Spectrummer circuits.
      The first uses the 74HC14 and LM324 or LM339 chips while last two
      circuits both use a 74HC240 chip.

      They are all designed to drive three or four single LEDs or a single
      RGB LED to provide full range color variations.

      There are some solar powered variants but I can probably simplify
      further it to meet your particular application. Let me know.

      wilf



      --- In beam@yahoogroups.com, "cw_eubanks" <cweubanks@...> wrote:
      >
      > I recently got interested in BEAM having walked into RobotVillage
      here
      > in NYC. I'm looking to create some simple pummers for a start and
      I've
      > been looking through solarbotics.com and .net and I've ordered lots
      of
      > supplies already based on the simple designs included therein.
      >
      > For starters I plan to use the circuit shown on the solarbotics
      page
      > for BEP applications
      >
      > and also featured in MAKEzine.com's new article on pummers:
      >
      > http://www.makezine.com/blog/archive/2006/11/how_to_make_a_p_8.html
      >
      > I have two questions about this to accomplish the initial design(s)
      I
      > want:
      >
      > 1) Is it possible to have the light slowly come on as it does in
      decay
      > by altering this circuit only slightly and how? For one, I want a
      > nocturnal "flower" that very slowly illuminates and then very
      slowly
      > decays after a few seconds.
      >
      > 2) anybody got recommendations on finding supplies such as aluminum
      > sheets, thin gauge wire mesh, small tools, etc?
      >
      > thanks in advance,
      >
      > Chuck
      >
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