Re: [APD] Light Timers

["Gordon McLellan" <gordonthree at gmail_com>]

ok ... there is no easy way you will be able to "ramp up" the
brightness of a standard individual fixture (lamp + ballast), be it
fluorescent or metal halide.

modern dimming solutions require expensive ballasts that support
something called "10 volt dimming."  lets say, for example, you have
some of these ballasts... now you need something called a "lighting
controller" - often sold for high end homes and big office buildings,
to provide "lighting moods".   a programmable lighting controller
would manage the gradual ramp up and ramp down dimming stages. 
However, you are looking in the neighborhood of $800-2000 USD for such
a controller (again _high_end_homes_).  these prices are due to the
market being extremely small - there is probably $20 worth of
technology in one of these controllers (as well as lots of design time
hours).   someone with electronic engineering experience could
probably build one in a few hours - my choice would be a software
solution, using a PC or Microcontroller.

my suggestion is to use multiple inexpensive fixtures to simulate the
gradual brightening of the morning sky, and gradual dimming of the
evening sky.   for this to work, all you need is simple timers, and
you stagger the on and off times to achieve the effect.  as each (for
example) 32 watt T8 strip light comes on (roughly $15 for a 4ft),
you'll gain another 600 lumens into the tank.... so perhaps choose a
warm-white bulb for the red glow associated with dusk and dawn, then a
few cool white bulbs for early morning and late evening, and then your
brilliant daylight halides for midday... then the timers reverse the
process with their turn off times.

Gordon


On 3/6/06, Jerry Baker <jerry at bakerweb_biz> wrote:
> Gordon McLellan wrote:
> > You may be able to recreate the dawn/dusk cycle with the addition of
> > some inexpensive (relative term?) fluorescent lights, reserving your
> > halides for a 4-6 hour "midday" period?
>
> My main problem is not being able to locate a dimming timer. I have only
> seen two in my entire life -- one for VHO and one for MH.
>
> --
> Jerry Baker
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> Aquatic-Plants at actwin_com
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