Astir Grow Led Panel Project...

psynobi said:

nice work weedman.. well done. your Nl is growing fine.

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tenthirty said:

Cycloptics would be a better choice for mixing chamber design.
That is if we are going to dream!!

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Bumping Spheda said:

Wouldn't the phosphor lens have to be huge then?

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The proposed Phase I research program will initiate a demonstration of new high-brightness, blue-light-emitting diodes (LED) required for effective plant growth on the Space Shuttle. Without a source of blue photons, dicotyledonous plants develop excessive hypocotyl elongation when illuminated solely by the red LED lamps now available as a photosynthetic radiation source for NASA. Filmsof indium-gallium-nitride (InGaN), the basis for bright-blue LEDs, will be grown by plasma-assisted metalorganic chemical vapor deposition (PA-MOCVD) and doped p-type by ion implantation. Use of a plasma source of nitrogen eliminates the harmful effects of hydrogen on inhibiting p-type doping that always accompany growth of nitrides from ammonia; functional LEDs require a pn junction and thus p-type doping is a critical materials issue. Introducing magnesium p-type dopants by implantation further avoids inadvertently incorporating hydrogen from organic-Mg doping sources. Phase I will establish conditions for materials deposition and p- type doping of InGaN, including an annealing schedule; preliminary assessment of the role of blue GaN LEDs on plant growth will be carried out by the Botany Department of the University of Wisconsin. Optimization of blue LED performance will be undertaken in Phase II. Here we shall extend the work to create a tandem red/blue InN/GaN LED which can emit all of the photons needed by plants raised in space. Grown as a large area film on a totally transparent substrate, this light-source approach will avoid the costly assembly of tiny LED dice. Because alloys of the III-V nitrides span the entire visible spectrum, they can be used in many commercial applications including full color displays for HDTV; indicator lights and alpha- numeric displays; free space communications (including optical interconnects in computers), and high density optical data storage, including advanced bar code readers.

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[h=3]Abstract[/h] Phosphor converted white LEDs are becoming more and more attractive for general lighting applications because of the steadily increasing luminous efficacy numbers reported by LED-suppliers. Despite these high numbers, a further significant improvement step can be made when a low-to-medium brightness (<500 kCd/m[SUP]2[/SUP]) source is acceptable. The wall plug efficiency of a blue LED is generally better than that of a conventional white LED made from the same die. To take full advantage of this, we have developed medium-brightness LED-modules (~150 kCd/m[SUP]2[/SUP]) for general lighting in which the phosphor is applied remote from the blue LEDs. By direct comparison with modules in which conventional high power white LEDs with almost identical dies are applied, we have shown that on system level the remote phosphor modules can have up to 50% better efficacy. Using a downlight module as a carrier, we have shown that in the relevant color temperature range of 2700 to 4000K a high CRI (>80) can be obtained in combination with a high luminous efficacy, while the optical efficiency of the module can be over 85%. A module efficacy of over 100 lm/W at 4000K with CRI 80 seems to be within reach, with a long-term expectation of over 180 lm/W. The remote phosphor LED modules deliver well homogenized white light with a Lambertian radiation profile. They are ideal for general illumination, as they combine glare reduction with high system efficacy and enable high optical efficiencies of the luminaries. The RP modules enable forward compatibility by well defined interfaces and optical properties that are decoupled from the actual performance, form factor and number of LEDs in the module. The Philips Fortimo downlight system is based on this remote phosphor concept, featuring forward compatibility and a total system efficacy (including driver) of over 60 lm/W under operating conditions using currently available Luxeon Rebel emitters.

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weedman420gr said:

I was looking for you Auto Master

I have questions..

About what week is she going to stop growing tall ? ( in 1-2 weeks ?)

I'm concerned that im not going to be able to fit it in there...

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stardustsailor said:

And who might that be,please ?
( I don't go outside "home" ,very often you see....)

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Originally Posted by Phaeton UVB and near infrared are used for non chlorophyll purposes on healthy well lit plants.

Originally Posted by Phaeton The spectrum of light the plant uses efficiently changes with the intensity. At low light levels red is used most then blue, just like the chlorophyl charts. As the light gets brighter more blue is used, and more. The break point is reached about 50% of max leaf capacity then green starts coming on. As the intensity continues up red and blue remain steady but green use continues to grow until at maximum it is almost half of all the light energy being used.

This is one reason why, even with the rather shitty, lopsided spectrum produced by HPS, one can still get good results with them:

(Shown: Eye Hortilux HPS vs. Photosynthetic Absorption Spectra Curve)

I'm glad we've finally gotten some good studies on green light over the past several years, as has been

This image has been resized. Click this bar to view the full image. The original image is sized 801x530.

Now, let's look at all of them superimposed over the PRC:

(note: neutral white I called 'normal white' here for some reason. Wonder what I was smokin' at the time...<whistles>)

As one can see, the CREE Neutral White (I call it 'Goldilocks', because it's almost 'just right'

) has a RSPD that still allows nearly ~25% of its total power in the blue range (and plants only really 'need' ~8-10%), and more that 1/3 of which (i.e. the area under the curve) is over ~580nm or so (which has a Photosynthetic RS of over 90%!) - which is much better than even your typical 'Enhanced HPS'.

Chlorophylls are readily extracted from (soft) leaves into organic solvent and separated chromatographically into constituent types, most notably chlorophyll a (Chl a) and chlorophyll b (Chl b). These two chemical variants of chlorophyll are universal constituents of wild vascular plants and express highly characteristic absorption spectra (Figure 1.. Both chlorophylls show absorption maxima at wavelengths corresponding to blue and red, but chlorophyll assay in crude extracts, which inevitably contain carotenoids as well, is routinely based on absorption maxima in red light to avoid overlap with these accessory pigments that show strong absorption below 500 nm. Absorption maxima at 659 and 642 for Chl a and Chl b respectively would thus serve for assay in diethylether, but these peaks will shift slightly according to solvent system, and such shifts must be taken into account for precise measurement (see Porra et al. 1989 for details).


Chl a and Chl b differ with respect to both role and relative abundance in higher plants. Chl a/b ratios commonly range from 3.3 to 4.2 in well-nourished sun-adapted species, but can be as low as 2.2 or thereabouts in shade-adapted species grown at low light. Such variation is easily reconciled with contrasting functional roles for both Chl a and Chl b. Both forms of chlorophyll are involved in light harvesting, whereas special forms of only Chl a are linked into energy-processing centres of photosystems. In strong light, photons are abundant, consistent with a substantial capacity for energy processing by leaves (hence the higher Chl a/b ratio). In weak light, optimisation of leaf function calls for greater investment of leaf resources in light harvesting rather than energy processing. As a result the relative abundance of Chl b will increase and the Chl a/b ratio will be lower compared with that in strong light. As a further subtlety, the two photosystems of higher plant chloroplasts (discussed later) also differ in their Chl a/b ratio, and this provided Boardman and Anderson (1964) with the first clue that they had achieved a historic first in the physical separation of those two entities.

Carotenoids also participate in photosynthetic energy transduction. Photosystems have an absolute requirement for catalytic amounts of these accessory pigments, but their more substantive involvement is via dissipation of potentially harmful energy that would otherwise impact on delicate reaction centres when leaves experience excess photon irradiance (further details in Chapter 12). Carotenoids are thus regarded as &#8216;accessory&#8217; to primary pigments (chlorophylls) and in molar terms are present in mature leaves at about one-third the abundance of Chl (a + b).

Obviously, chlorophyll in leaves is not in solution but exists in a gel-like state where all pigment molecules are linked to proteins, and absorption spectra differ accordingly (see Evans and Anderson 1987). In particular, light-harvesting Chl a, b&#8211;protein complexes (LHC in Figure 1.8, lower curves) develop a secondary absorption peak at 472 nm with a shoulder at 653 nm, while the Chl a of photosystem II reaction centres shows absorption peaks at 437 and 672 nm (compared with 429 and 659(662 ? ) nm for purified Chl a in ether; Figure 1.8, upper curves).








Subtle alterations in the molecular architecture of chlorophyll molecules according to the particular protein to which they bind in either light-harvesting or energy-processing centres are responsible for these shifts in absorption peaks, and for a general broadening of absorption spectra(=>white light ? ..) (compare lower and upper curves in Figure 1.. Such effects are further accentuated within intact leaves by accessory pigments and greatly lengthened absorption pathways resulting in about 85% of visible wavelengths being absorbed (Figure 1.9). Any absorbed quanta at wavelengths below 680 nm can drive one electron through either reaction centre.

Maximum quantum yield (Figure 1.9) occurs when both reaction centres absorb equal numbers of such quanta.

When one photosystem population (PSII) absorbs more quanta than the other (PSI), excess quanta cannot be used to drive whole-chain (linear) electron flow. Quantum yield is reduced as a consequence, and leads to a slight discrepancy between in vivo absorption maxima (Figure 1. and quantum yield (Figure 1.9).

Although UV wavelengths are absorbed by leaves and would be capable of driving photosynthesis, such short wavelengths are damaging to biological systems and plants have adapted by developing a chemical sunscreen. Consequently, the quantum yield from these wavelengths drops off markedly below about 425 nm. Beyond 700 nm (infrared band) absorption drops to near zero, and forestalls leaf heating from this source of energy. However, quantum yield falls away even faster, and this &#8216;red drop&#8217;, though puzzling at first, led subsequently to a comprehensive model for photosynthetic energy transduction, outlined below.

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Abstract

It has been proved that monochromatic or compound light-emitting diode (LED) or laser diode (LD) can promote the photosynthesis of horticultural crops, but the promotion of polychromatic light like white LED is unclear.

A new type of ultra-bright white LED (LUW56843, InGaN, nullset 5 mm, 150mW, 15000 mcd, wavelength range: 400~720 nm) was selected to make up of the supplemental lighting panel (200×300 mm[SUP]2[/SUP]), on which LEDs were evenly distributed with 90 branches. Drive circuit was selected to power and adjust light intensity. System performance including temperature rise and light intensity under different currents and vertical distances were tested. Photosynthesis of sweet pepper and eggplant leaf under white LED was measured with LI-6400 to show the supplemental lighting effects. The results show that LED system can supply the maximum light intensity of 300 &#956;mol/m[SUP]2[/SUP] .s at the distance of 100 mm below the panel and the temperature rise is higher over 13 °C on the surface of LED encapsulation, but hardly changes 100 mm far away the panel. For both of the two vegetables net photosynthetic rate became faster when white LED system increased light intensity. Compared with sunlight and plant growth fluorescent lamp, white LED's promotion on photosynthesis is inferior because its spectra is unreasonable with more blue light and less red light. Therefore, the unreasonable spectra become the major constraint of its application, but the potential of white LED application into vegetable crop production is prospective.

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PetFlora said:

I offer you (in my mind's eye) a Fiat, a lessor version of your Ferrari

An arching rail, with 3 panels (think balance beam trapeze artist). Arching, as in curved rail, where rail section is from a much larger circle. Distance from TDC to lowest point ~ 6"/15cm (Probable length ~ 24"/ 60cm). Would this allow 3 panels to do the work of 5+?

Not quite this simple as how to move it back & forth without falling off... I'm thinking 4 wheels above and below to secure. Of course physical stops on each end of the arc

May still be a Ferrari, but a Dino

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staf82 said:

SDS I'm really impressed with your light and seeing it has made me want to make my own diy led lihave ordered my leds but have no idea about the size of heatsink needed? How big is yours? I'm planning on having 16 leds on each one all running at 700ma and was hoping you would be able to assist me on working out the size needed many thanx

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stardustsailor said:

Pet,right now I'm so stoned by the led-grown, half-dryed, herb of mine ,that I've to ask for a ...drawing of that ....
Sounds interesting ....

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weedman420gr said:

Hola growers and friends,

Day 34 today...she's becoming a monster...

Had to LST all of her again today (hope for the last time)



Also,i lowered the pot for better air circulation and more free space!

Here are some pictures(i think flower has started some days ago!! Lets see!)

Enjoy...!

*Last picture is last year's Nirvana auto NL under 70watt HPS at Day 32
**&#952;&#945; &#947;&#953;&#957;&#949;&#953; &#964;&#951;&#962; &#954;&#959;&#955;&#945;&#963;&#949;&#969;&#962;

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picolada said:

nice job there my friend but i suggest you not to use wire for your lst,it could
hurt your plant as it grows..
keep on!!

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