Re: [APD] LED Lighting

[Wright Huntley <whuntley at verizon_net>]

> Message: 11
> Date: Mon, 29 Dec 2003 16:17:48 -0800 (PST)
> From: "S. Hieber" <shieber at yahoo_com>
> Subject: Re: [APD] LED Lighting
> To: aquatic plants digest <aquatic-plants at actwin_com>
>
>
> --- Wright Huntley <whuntley at verizon_net> wrote:
>
> > > > > Message: 6
> > > > > Date: Mon, 29 Dec 2003 13:14:57 -0800 (PST)
> > > > > From: "S. Hieber" <shieber at yahoo_com>
> > > > > Subject: Re: [APD] LED Lighting
> > > > > To: aquatic plants digest <aquatic-plants at actwin_com>
> > > > > 
> >
> > > . . .It 
> > > certainly isn't up with the CF lamps I was immersing a
> > > couple of years 
> > > ago. Those carried some truly lethal Voltages/currents
> > > and the current 
> > > in water would have been more than non-trivial!
>
>
> You were putting your bulbs in the water on purpose? I know
> this is done with sleeveless UV lamps but don't recall any
> other examples.  If intentional, what were you up to?

No. Not in water. I had them in a plastic tube, but sweated a lot about 
the hazard if one leaked or cracked open.

Illumination from below the water line is very unrestricted by such 
nasty optical effects as light-piping. You have never really seen them 
until you see a herd of Rasboras (I like the *espeis* that Amanosan 
prefers), illuminated from inside the tank. I love Lampeye killifish and 
most of them become spectacular when the light is no-longer propagating 
straight downward. Like windowlight, but way better.

> > > > > Wright do you really think transistors are needed in a
> > > > > power supply? Low voltage DC, a rectifier and some
> > > > > resistors ought to do the job. But with enough to light
> >
> > > a
> >
> > > > > tank, even the resistors would be redundant, no?
> >
> > > The high impedance of a transistor collector is probably
> > > cheaper than 
> > > all the stuff you have suggested.  Don't forget that
> > > transistors are 
> > > often way cheaper than resistors, these days, unless you
> > > want 
> > > individually packaged ones.  Resistors can act as
> > > current sources, 
> > > but must waste a lot of power to do so, and I find extra
> > > heat a problem 
> > > with most lamps. A 5V wall wart with a simple transistor
> > > array driving 
> > > arrays of several LEDs in series is a pretty cheap
> > > "ballast" as such 
> > > things go. Yes it needs at least one or two resistors,
> > > but they need not 
> > > be conducting all that current and creating heat.
> > >
> > > My ideas may be a bit overdone,
>
>
> Not overdone if you supply us with some schematics. I can
> solder but I can't design the circuit

Find me a cheap supply of LEDs and I'll work on it. :-)

> > > but I would like to
> > > roughly regulate the 
> > > current to maintain constant output with age, temp, etc.
>
>
> And to keep things kosher when one or more of the LEDs goes
> south?

That is pretty rare, which is why cities like them for traffic control. 
Ever seen a burned out one in a traffic light? :-)

> > > Wouldn't that 
> > > be kind of nice? Cheap, too, I suspect, compared to the
> > > cost of the 
> > > LEDs. Traffic lights have made red and green into cheap
> > > commodities, but 
> > > good blue is still a big problem, both in cost and maybe
> > > lifetime. Cheap 
> > > 10,000 K may still be a way off. 
> > >
> > > I see more problems working out mountings and attractive
> > > housing. How do 
> > > we keep food from fouling them, etc.? Will algae quickly
> > > grow on the 
> > > plastic lens and turn them off?
>
>
> You could keep them above water, no?

I wouldn't be interested, having experienced the advantages of immersed 
lighting. <g>

> > > Gotta go chop some wood. Came home from So.CA to
> > > frozen-up water lines, 
> > > last night. 
>
>
>
> Sorry to hear that. Beena there; mopped that.

Luckily no burst, just no flushing for an uncomfortable span. :-)

> > > Finally cleared by this afternoon, but the
> > > snow level is 
> > > down about 100' above the valley floor and dropping. Come
> > > to think of 
> > > it, I'd like some lights that put out a *lot* of heat,
> > > right now. 
>
>
> Think Incadescent, think heat 

My reading lamp by the bed is a 100W halogen. Feels nice and toasty now, 
but have to move it away in August.

Wright

Wright Huntley -- 760 872-3995 -- Rt. 001 Box K36, Bishop CA 93514




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