Light loss is the same as efficiency. If you have a system that is
80% efficient, you have a 20% light loss factor. My point with the
> Light loss isn't as important as just getting the light through,
> IMHO; at that point it's all about efficiency.
> --- mcc...@hotmail.com wrote:
> From: McCrum <mcc...@hotmail.com>
> To: "NYCResistor:Microcontrollers" <nycresistormicrocontrollers@googlegroups.com>
> Subject: [NYCR:Microcontrollers] Re: making fresnel lenses with makerbot
> Date: Thu, 26 Apr 2012 11:19:45 -0700 (PDT)
> Well, that had been my point. You could not make something and
> achieve the same amount of light.
> On Apr 26, 1:25 pm, "Ted Hayes | Limina.Studio"
> <liminastu...@gmail.com> wrote:
> > Sure, of course. I'm just thinking out loud from a cost point of view; in the interest of making something really cheap that still gets some of the job done ;)
> > _t3db0t
> > On Apr 26, 2012, at 12:38 PM, McCrum wrote:
> > > Well, you're taking light from the sun, reflecting it off a surface
> > > and back towards the sun where it would presumably meet the "in"
> > > portion of the optic. This "solar cooker" works because you're
> > > heating up the sun side as well as the dark side.
> > > In terms of reflectance, NASA gets about 95% from their mirrors. A
> > > white ceiling gets about 80%. So even with the best technology on
> > > earth, we're already down 5%, expect good mirrors to get, say 90%.
> > > But let's say that we're redirecting an additional 20% of surface area
> > > to that point, through reflection we're now getting 108% (.9*120) of
> > > just plain sunlight.
> > > Now, we're also taking an opaque object (the fiber head) and putting
> > > it in the middle of the point where the sun is, casting a shadow on
> > > the reflector, causing even more loss. At that point, we're pretty
> > > close to the original 100% of just pointing it at the sun. in the
> > > first place but with a lot more work and more things to fail at
> > > various times. Once you start adding in reflectance multipliers light
> > > intensity starts to drop really fast.
> > > On Apr 26, 11:35 am, "Ted Hayes | Limina.Studio"
> > > <liminastu...@gmail.com> wrote:
> > >> Yeah, but couldn't it still be used for that purpose? The reflector faces the sun and the fiber optics are placed at the focal point and routed to wherever they need to go... A bit janky, but cheaper, I guess.
> > >> -t3db0t
> > >> On Apr 26, 2012, at 11:12 AM, McCrum wrote:
> > >>> I like this, but it's a reflector to bounce light back at a point and
> > >>> reflect sunlight back towards the source, essentially making it do a
> > >>> 180 degree turn. Dave is looking to focus the light from the sun to a
> > >>> point and keep it going in the same direction.
> > >>> On Apr 26, 10:23 am, Angelo Tartanian <chunkymidgetmon...@gmail.com>
> > >>> wrote:
> > >>>>http://hackaday.com/2012/01/09/diy-fresnel-reflector/
> > >>>> On Thu, Apr 26, 2012 at 10:15 AM, astrida <vastr...@gmail.com> wrote:
> > >>>>> You might be able to laser etch something to get a fresnel lens
> > >>>>> effect. I'm thinking etching or cutting clear acrylic might work.
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