| | Re: What? Who Me ... A Guru?
Well .. it's been quite a few more years now and I have not yet written the article on LED's. Why? Every time I go to sit down and look at the data, the technology improves tenfold. Many new and exciting advances happen in LED tech every few months and it is tough to keep up with. Also the companies that are producing LED lighting for aquaria can't keep up, so the products are obsolete once they release them.
I do have some data, some designs and some results from my own experiments. I have been playing around with multiple color LED systems. Large arrays of lower power high intensity LED's with a custom electronic controller that can adjust the color temperature (and even light intensity levels) and therefore fine tune spectrum for individual plant species or groups of species. Even to the point where you can change the color temperature with the array of LED's to have different color temps & intensities in different sections of the tank.
The idea came to me working at a concert. I was back by the drum kit grumbling at the drum tech for moving my microphones during the set-up. There was one of those huge video projection screens along the back of the stage. I noticed how the colors were changing on the white drum heads while the video techs were running tests. These screens use tens of thousands of these tiny tri-color high intensity LED modules arranged in huge computer controlled arrays. Each module is self contained, waterproof, and has three LED's which make up an RGB (Red-Green-Blue) cluster on a black background. At the time the techs were adjusting for color temperature and on the drum heads I could see the subtle changes in the white light. They were essentially changing the spectrum of the white light. A little "light" went off in my head, and of course I was thinking about fish tanks & not concert lighting. Crazy.
This system works really well in the very very large aquascapes in particular. Currently the controller is hooked up via a USB port to a computer, running a program I wrote to program the LED array. You can design the lighting scheme in advance using a virtual tank graphical interface, connect the computer to the controller and upload the settings, then disconnect the computer. You can also do the programming while the computer is connected to the controller & the array in real-time. It's kinda crazy, but it works.
I was sitting there one weekend in front of my big tank, with a spectrometer (a device that measures and graphs out spectrum), my lighting system and my laptop. I was turning on & off individual LED clusters to see which cluster (or groups of clusters in some cases) was illuminating which plant in my big tank. Then I would adjust the spectrum and light levels for that species. The array uses 60 RGB LED modules on a 260gal tank. Due to the high output of these modules and the large number of modules in the array, they are running only at about 27-34 percent output per module. It was crazy overkill, but it was experimental so it didn't matter.
The plants are growing very well, and the Co2 absorption levels are through the roof. I'm using 30% more Co2 with these settings, a good indication of the plants health due to species tailored spectral lighting. I have Cabomba sitting next to Java Fern and each is receiving a specific spectrum and light intensity appropriate for each species. Here lies the great promise of LED lighting. A very specific targeted lighting down to specific species requirements and being able to selectively illuminate specific individual plants. Something not achievable with standard high-intensity light-flooding technologies like Compact Florescent or Halide lamps. Also this array uses at max light output only about 200 watts of power, including the controller. However it can produce nearly 30 times the light output of a similar wattage CF system.
You can also set what I call a "show mode" where the color temps and intensities are set to solely bring out the color of the fish and plants temporarily, like when you have guests over for a few hours. Wanna talk about vibrant reds in your Cabomba furcata or Rotala macrandra? Wanna make a school of a hundred Neon Tetra's explode with shimmering blue & red brilliance? It works really well. It may be cheating yes, but your guests won't care, they just go "ooooo ... aaahhhh". And when they leave, switch it back to "grow mode". Only your fish have to know, and heck they can't snitch anyway!!!
However, and this is a huge caveat, the cost of a system like this is prohibitively high to the extreme. LED tech, especially of this complexity, is very expensive at this time. Well outside the realm of the idea of DIY. Also the construction of this type of system may be outside the abilities of most DIY builders. However, this was done as an experiment; to collect empirical data, test whether theory can be developed into practical design, and to explore the full potential of the technologies involved.
I have also been playing around with more practical designs. One uses high power white LED's with only a few LED devices in a hood design. Another uses multiple mid power LED's to reduce heat issues, plus other more practical designs. All sorts of things. The jury is still out. However because of the heightened interest in LED tech right now in the mainstream, due to energy concerns mostly, I'm still always trying some new devices and revise my designs. These new technology developments are happening monthly right now. There is great promise in a new generation of LED devices that will be coming out in late 2012, and I am waiting on the data with great anticipation.
I will follow these technology developments. Once I come up with something lasting, that is comprehensive, and has both complex and also simple designs, another DIY treatise will be authored. This time, A Treatise on DIY LED Based Lighting Systems for Planted Aquaria. There, I already wrote the title.
Damn, why do these things always take years?! Last time out I spent two years researching solely on the subject of the biology of yeasts, for gosh sakes!!! I least this time I'm in my natural realm ... electronics.
And no ... No name dropping on the Metal bands. That's just not cool!
Stay tuned ...
Last edited by John LeVasseur; 04-30-2012 at 12:25 AM..