Gomer Posted January 23, 2008 Share Posted January 23, 2008 420 technically is Visible (400-700nm). The UV you get from metal halide is below 400nm. UVA, long wave, or black light 400 nm - 320 nm UVB or medium wave 320 nm - 280 nm UVC, short wave, or germicidal Below 280 nm Also While "black lights" do produce light in the UV range, their spectrum is confined to the longwave UVA region. UVA is considered the safest of the three spectrums of UV light. Unlike UVB and UVC which are responsible for the DNA damage that leads to skin cancer, black light is limited to lower energy, longer waves and does not cause sunburn. UVA is capable of causing damage to collagen fibers, so it does have the potential to accelerate skin aging, cause wrinkles and potentially destroy vitamin A in your skin. I guess the wavelength you want is more dependent on the contributions of various absorbers Link to comment
coolwaters Posted January 23, 2008 Author Share Posted January 23, 2008 aww guess im set it so that my UV will turn on when no one is home XD thanks for that line graph. Clams have a lot of Carotenoids? Link to comment
coolwaters Posted January 23, 2008 Author Share Posted January 23, 2008 ok 2 of my Cree blue LEDs popped off the star board...but that maybe a good thing.... i'll try to mound them and see wat happens. BTW Cree LEDs are like the hardest to solder (next to rebels) Link to comment
Hans Dorn Posted January 23, 2008 Share Posted January 23, 2008 I remember reading somewhere on here that the zooxanthellae in coral (and probably clams) are using chlorophyll c. I couldn't find any good spectra of chlorophyll c online, but what I found suggests that chlorophyll c is very similar to chlorophyll a. This would mean that blue leds aren't putting out much useful light for our coral. Royal blue is slightly better, but still drops off pretty much at 420nm: (lifted from the cree XR-E datasheet) It seems to be a good idea to use 420nm LEDs instead of blue ones. Even if they are less efficient than blue ones, their useful light output may well be higher. Regards Hans Link to comment
coolwaters Posted January 23, 2008 Author Share Posted January 23, 2008 i wonder if LEDs really emit 100% pure light... lol i was hoping that the white will bring down the blue to 450nm... and yes i did heard that something in the 450-470nm will yield the best results. Link to comment
Gomer Posted January 24, 2008 Share Posted January 24, 2008 i wonder if LEDs really emit 100% pure light... lol i was hoping that the white will bring down the blue to 450nm... and yes i did heard that something in the 450-470nm will yield the best results. what do you mean pure light? What do you mean white shifting blue? Link to comment
NanoReefGuy Posted January 24, 2008 Share Posted January 24, 2008 If you need UV LED what about these: http://www.kaidomain.com/WEBUI/ProductDeta...spx?TranID=3246 410nM should have a wide enough spectral distribution to cover chloryphyl A. At the very least is should fluoresce your corals Balanced with some regular blue LED to cover B & C maybe? What do you guys think? Cheers NRG Link to comment
Hans Dorn Posted January 24, 2008 Share Posted January 24, 2008 I wonder if those guys over in Hong Kong will start adding data sheets to their products anytime soon After some googling I found that those UV LEDs have about 17% efficiency - 17% of the input power gets radiated as UV light. A decent royal blue LED will put out twice of that. IMO the UV LEDs would give more photosynthetically usable output, judging by the chlorophyll a spectrum posted here - I might be totally wrong, though Maybe someone with a better background in this topic could chime in? Regards Hans Link to comment
coolwaters Posted January 24, 2008 Author Share Posted January 24, 2008 pure light as in...if u get a blue LED it will only emit 100% blue wavelengths. not sure about the white. about the shifting nevermind. i was thinking that since blue light raises the color temp of white light is it vice versa. but nevermind about that. about the 3w thats seems a bit much tho. im trying to keep that at a low since then can cause some damage. Link to comment
Gomer Posted January 24, 2008 Share Posted January 24, 2008 pure light as in...if u get a blue LED it will only emit 100% blue wavelengths. not sure about the white.about the shifting nevermind. i was thinking that since blue light raises the color temp of white light is it vice versa. but nevermind about that. Colored LED for the most part, have a (i think) Lorentzian wavelength function. Think bell curve. The wavelength specified is the maxima. The other component (which you have to get on spec sheets is the width of the peak. If you want an exactly 400nm LED, you will not get it. You cant even get PURE 400nm light from the best laser in the world. It is (afaik) even theoretically impossible. Depending on the inorganic/semiconductor responsible for the band gap emission, you will have various widths. White LEDs on the otherhand are entirely different beasts. They are Blue leds that have a phosphor coating to convert the blue light to another color. Your eye mixes the colors and interprets white. This is similar to fluorescent lamps. The murcury inside generates a deep UV emission (why UV steralizer bulbs have no coating). Lamp companies the add a coating to convert this deep UV to various colors which our eyes mix to for various "shades of white" Here is a white LED spectrum. The left peak is the natural emission. The broad right hump is the phosphor emission So there you have it. There is no such thing as a "pure" color LED. This leads me to another issue I was thinking about the downfall of LEDS. which I may bring up in another thread: the fluorescence pitfal. Link to comment
evilc66 Posted January 24, 2008 Share Posted January 24, 2008 This leads me to another issue I was thinking about the downfall of LEDS. which I may bring up in another thread: the fluorescence pitfal. Tease Link to comment
coolwaters Posted January 24, 2008 Author Share Posted January 24, 2008 dam here i thought lasers are pure wavelengths guess its impossible to have the spectrum go straight up and down. Gomer thanks for that educationally report. i figure why Cree has the best blue LEDs....think its like 46lumens atm. Link to comment
coolwaters Posted January 29, 2008 Author Share Posted January 29, 2008 i got one of those plastic len sheets forgot wat they were called... anyways im off to pick up my packages...i hate USPS they dont leave packages on my doorstep... its been like 3 weeks =P hopefully i got all my LEDs....but for sure i got the lenses...and some other things i forgot about... Link to comment
fatrip Posted January 29, 2008 Share Posted January 29, 2008 coolwaters, on yuor latest picture you have 5 stars but one is a different color, what LED is that one? and what color are the 8 that are around the center?? Link to comment
coolwaters Posted January 29, 2008 Author Share Posted January 29, 2008 you mean 10? the white base LEDs are cool white. the 4 in the corners are blue. the center is RBG (red blue green) i'll be only running the green and blue. ok heres an product update. i just got all my orders. 8 blue 5 red 3 green. 10 optical reflectors and one tri-reflector. also 5 Cree WD bin LEDs. it seems that they messed up on the order and gave me 3 extra green....so what am i going to do with all of thos? im not planing to use any....dam compulsive buys.... Link to comment
coolwaters Posted January 29, 2008 Author Share Posted January 29, 2008 heres a pic of wat i got. i wanted to test out the tri lens but its not that good. eats up too much space. the ones in mylar bags are the blue, green, red LEDs. i'll try out the single lenses. if u look closely u can see the UV LED. i just wished i bought more XD Link to comment
fatrip Posted January 29, 2008 Share Posted January 29, 2008 yea i ment 10 sorry. what does XD stand for i had looked back threw but i couldnt find it. i am sorry that i am asking so many ? but i am going to be building one and i i want to know all the lingo... Link to comment
Hans Dorn Posted January 29, 2008 Share Posted January 29, 2008 Hi Coolwaters, I'm curious to see the light pattern that your lenses create. I fancy getting some myself I bought a bunch of flashlight reflectors at DealExtreme, but they create an awfully bright spot with lots of sidespill. That's pretty useless for lighting a tank, D'Oh Regards Hans. P.S: Post some shots of your UV LED ASAP Link to comment
coolwaters Posted January 29, 2008 Author Share Posted January 29, 2008 yea i ment 10 sorry. what does XD stand for i had looked back threw but i couldnt find it. i am sorry that i am asking so many ? but i am going to be building one and i i want to know all the lingo... lol i forgot to put a period. "if u look closely u can see the UV LED. i just wished i bought more. XD" wat kind of flashlight reflectors did u use? i recommend getting plastic since is much clearer and light weight. i'll get everything wired up and going soon. im in kind of a pickle...i have a bunch of different LEDs but some of them run on different currents....i only got 700mAs and a optional 750mA regulator boards that i dont want to use. im thinking i should just run the UV bulb at 700mA but the recommended is 350-500mA. is 700mA ok? Link to comment
coolwaters Posted January 29, 2008 Author Share Posted January 29, 2008 where did you find out that solaris is using green LEDs now? Link to comment
Hans Dorn Posted January 30, 2008 Share Posted January 30, 2008 wat kind of flashlight reflectors did u use? i recommend getting plastic since is much clearer and light weight. im thinking i should just run the UV bulb at 700mA but the recommended is 350-500mA. is 700mA ok? I got these from DX. Best part is that my star boards wouldn't even fit in. I butchered one with a dremel to get the LED into focus. Good thing I went and ordered a bunch of them Don't overdrive your UV LED, I'm pretty sure it won't like it. You could try running it parallel to a blue one, probably with a small resistor to match the VF of the LEDs. Check with an ampere meter. Regards Hans Link to comment
coolwaters Posted January 30, 2008 Author Share Posted January 30, 2008 im never using resistors... i'll just run them in parallel with one of blue then. they should draw about the same amps. u should have gotten these they fit perfectly on the dome of the LED. btw dont use super glue that stuff will cloud your LEDs...i ruined quite a few in the past but they were just crappy K2 luxeons... i used welder glue and it works fine. its a built in light diffuser so mixing light with it is much easier. im going bare LED with a len sheet. Link to comment
Hans Dorn Posted January 30, 2008 Share Posted January 30, 2008 Watching out for your results I'll probably redo my light with a big a$$ heatsink and a bunch of these lenses. Regards Hans Link to comment
coolwaters Posted January 30, 2008 Author Share Posted January 30, 2008 u dont really need a big heatsink. my CPU heatsink is enough to cool down 30 watts with no heat. at 6v fan. and its a pretty small heatsink too. if u can get a copper plate as the base. and aluminum fins. but if u want to save money just get a CPU heatsink. im very pleased with mine. Link to comment
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