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Yet another LED build thread


DarkDevil

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I am trying not to be an outcast, so I am gonna use some high powered LEDs and join the rest of the cool people :) It is not finished yet, but I am at a stage that I am almost done and want some input or criticism before I move on to cutting and hacking major things.

 

A little background, this setup is gonna install inside the hood of an Oceanic 8G. I am going to gut all the OE stuff, replace with better fans, drill more air vents and shove the LEDs with heatsink in. The power supply and the rest of the "brain" is going to be inside an external box somewhere far away from the water. blar blar blar, nobody likes to read, so on with the pictures:

 

light.jpg

 

This is my basic calculation and simulation on the design and how the light is going to hit inside the water. Obviously the water is going to reflect, refract, deflect the light with all kinds of weird stuff, this is just merely an idea of how it might look.

 

P8170072.jpg

P8170074.jpg

 

Here are the main parts, order from www.cutter.com.au, great price and fast shipping. These are Cree XR-Es, 6 royal blue, 8 cool white(10k bin) and 1 red. Two 1A buckpuck, I was gonna use LM3404 at first, but I wanna keep it simple so I use buckpuck. If I were to do it again, I would stick with my original design and use LM3404 instead. And last it's the optics, it's a 40 degree Cree optics. I recently changed my optics to just using reflectors, here are the differences:

 

P9170087.jpg

P9170090.jpg

 

the reflector is smaller and easier to install so I go with that instead.

 

For installing the Cree LEDs, I use a 1/16" Copper C110 plate, I use copper instead of aluminum is because I want maximum heat spread throughout the whole plate and transfer to the big Al heatsink on top. It's a bit expensive ($5) but I hope it will get the job done. First, I scribe the lines on the copper plate to make the outlines how I want the LEDs to be.

 

P8200076.jpg

 

Then I use arctic silver epoxy to stick all the LEDs in place.

 

P8210082.jpg

 

Then is the no-so-fun part of soldering the darn tiny things together...

 

P9070083.jpg

 

So far so good? Then the real interesting part begins, the "brain". I use a 24V 65Watt AC/DC power supply to power 2 1A buckpuck. So the configuration is: 6 royal blue LEDs are running @ 1A on one buckpuck, and the rest of the white and red are running @ 500mA on the second buckpuck. My idea is that I can control individual intensity of either blue or white to vary between around 10,000K color temp to 20,000k+color temp if I ever need to. Second, these 2 buckpucks are controlled by a PIC circuit to turn on and off automatically with respect to time and with slow dimming function. I used a simple SX28 chip and a DS1302 time chip to do the job. Simple circuit, simple program. I made a small clip showing the automatic dimming:

 

th_P9170086.jpg

 

I programmed it to ramp down and up within 1 minute for demo purposes. For the final setup, I am thinking to ramp up and down within 1 hour of time to replicate sun up and sun set. Also I am going to program it to turn on at 11:00am and turn off at 11:00pm.

 

That's pretty much most of it, next step is take the hood off the aquarium and start hacking away. Feel free to ask question, give me more ideas, criticize, or simply tell me to go out more and do something better with life. :D Enjoy.

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u used copper? lol i bet u spent more money on the heatsink then anything else.

btw your going to need some fins to make your heatsink more efficient.

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oh no no, the copper is just a thin plate, that plate connect to a 1.5" Al heatsink. You can actually see the Al heatsink with fins under the copper plate in the video. I calculated the c/w that the heatsink I choose should be fine with the enclosed area.

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that's one of of next concern right now, is to get good contact between the copper plate and aluminum heatsink, either I mill them to absolute flatness then just clamp them together with some paste between, or I need to find a good thermal "mat" and stuck it between the two. Still have to research on a good thermal "mat"

 

I use red is because of 2 reason. first, I want to bring a bit of warm color out of the corals, similar effect when you use UV/violet light to bring out the fluorescent color. Second, chlorophyll need a bit of red spectrum, more then they need green. So when I did my research, I was thinking choosing either red or blue LED for the center. I end up using red becuase I will have some red and pink yuma and zoa in the tank :) I also might add a couple UV/Violet 5mm LED to the mix but I need to re-measure the hood and decide the best location for those.

 

Those regulator you showed are nice, but it only goes up to 18V, 750mA and no control/PWM port. It's actually a good choice if someone just want to do something really simple for less headache and save some cost. but as I said, if I would do this again, I wouldn't choose buckpuck as well. I would do LM3401 or LM3404, it's cheap also, but you just need couple resistors and capacitors along with it.

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Hmmm... I just replaced the heatsink for my comp and I used some artic silver

 

basically you just put a small amout between the copper an the processor and sqeeze them together to get even coverage for better heat transmission. Btw I'm not sure that a perfect mill would be necessary since the compound is pretty heat conductive and would fill minute gaps in either material

 

ohh yaa... sweet build ;)

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Nice start.

 

On the heatsink, unless you mill both surfaces flat, the best way to maximize thermal transfer is going to be to bolt the two parts together at close intervals. A small amount of thermal paste will be required, but it will perform much better than using a large TIM (thermal interface material). I have never found them to be as effective as good contact. Make sure there is absolutely no current running through the heatsink as you will start getting galvanic corrosion between the two metals.

 

Which reflectors did you end up using?

 

I look forward to seeing more.

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Thank you for the kind words. The aluminum heatsink bottom is milled, I haven't checked the flatness, but I think it's good enough, it's the copper plate that wrapped on me since it's only 1/16". When I put the 2 together, there are some gaps that I notice are at least 0.5mm. So if I were to thermal paste the whole thing 6" x 5" it's gonna get costly with arctic silver. I may take evilc66's advice and bolt those together at close intervals and use ceramic paste instead. that means a lot of drilling and tapping...

 

oh and I already made absolutely sure no current leaked out from the LEDs, that's also the reason why I move all the components remotely so less error may occur.

 

I will end up using the silver reflector you see in the pics, not the lense one. They both have pros and cons by just looking at the specs the company provides. I will do more testing afterwards, when I order my apogee quantum sensor. Specs means nothing without real life experiments, but for now, reflector it is.

 

For a parts list, I may add new things and reprogram the PIC later for more functions and versatility, but for now:

 

24V 65 Watt AC/DC Meanwell power supply - $20.78

8x Cool White Cree XR-E (Q3 Flux, WA Tint) - $4.5 ea, $36 total

6x Royal Blue Cree XR-E - $4.5 ea, $27 total

Red Cree XR-C - $4

14x Khatod reflector KCLP17ST(35degree) - $4 ea, $56 total

2x 1A Buckpuck (3021-D-E-1000) - $18 ea, $36 total

7.5" x 6" x1/6" C110 Copper plate - $5

300mm x 101.6mm x 32mm, 0.04 C/W (w/ fan), Aluminum heatsink - $50

SX28AC PIC - $2.79

4Mhz resonator - $0.89

DS1302 Timekeeping chip - $4.98

32.768KHz crystal - $0.28

Battery holder - $1.14

CR1216 Lithium Battery - $1.08

Various wires, resistors, capacitors, solder - $5 max

My time for programming - Not worth squat :P

 

That's top of my head and from the receipt I can find, I might miss something. But the grand total is approx $250-$260 for now. I will add a LCD screen and some button and program a better user interface to control the lights later. But for now, I just want to shove this setup into the hood and make the corals smile :)

 

Feel free to ask, give ideas and criticize more. Thanks.

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Very nice build!

 

Next time skip the copper. As you realize there are issues with getting a good connection between the Cu and the Al. There are enough issues with the thermal connection to actually nullify the any advantage of the cu. But yet you are are now burdened by the sub mounting hassles. Yikes!

 

evilc66's; Advice is pretty much the only way to go. Lots of clamping.

 

In that regard you could ease things a bit. Rather than surrounding each LED with four screws find some small angle iron or square tubing. Then run a piece between each row. Put one screw on each end and maybe one in the middle. You want something that is real stiff, hence the angle iron. But don't use another metal, (gah!), use Al 'angle iron'. Most bigger hardware stores have that extruded anodized AL stuff. Some 3/8" or 1/2" would probably do the trick. The nice thing is that that 'angle iron' will also act as cooling fins.

 

Again, yours is one of the nicer builds I've seen...

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Thank you. My original idea is to stick the LED directly onto the back the heatsink, but I didn't find any heatsink that is the size I want in one big piece. Well, maybe I didn't look hard enough, and I didn't want to pay custom for it also. So I come up with this stupid idea that I am regretting now...

 

I did thought about making my own heatsink using L shape aluminum from hardware store, but I skipped that thought because the work might involve with it, so I went and order myself a real heatsink instead. well, as we all know now, turns out the work is pretty much similar if not harder. I will probably use the heatsink instead, since I already bought it, but we'll see how it turns out once I gut the hood out. I might still change.

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I realize you already have your heat sink but thought I could add a comment on them.

 

After a recent design. (I'm an EE) I found that Allied Electronics www.alliedelec.com seems to have the best bulk heat sinks for your $$.

 

Like these: Look at the bottom of the page.

http://www.alliedelec.com/Catalog/pf.aspx?FN=748.pdf

 

Any of those that have the fins off of one side would do a bang up job for your type PLEDs.

 

Note that they come in 4 foot lengths and one comes in a half foot length.

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  • 2 weeks later...

Hi, yet another impressive DIY LED thread !

 

How does the timing and dimming circuitry work? How did you program it? I always thought such a thing would be very costly but looking at your parts break down it's dirt cheap really. :) That's unless I would have to buy some kind of IC programming device to program the SX28AC.......

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The control portion of things can be done so cheaply now. With dev boards like the arduino's and pics of varying flavors under $50, you can do some pretty crazy stuff for cheap. There is a version of the arduino that has a serial port that you could hook up a simple 2x16 LCD and have visual feedback of your settings.

 

DarkDevil, how's the progress coming?

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There are couple ways to program different ICs, I do have a decent multi chip burner, but for programming the SX28, all you need is cheap USB programmer that cost $30. Or if you use Amtel PICs, all you need is to build a programmer for less then $5. And of course, there are so many dev boards out there like arduino and such. so there are many many ways, all depends on your preference and comfortable level of using which technology.

 

Reason I choose SX28 is because of the readily available codeset I can use and the chip itself is cheap ($3, or add $30 for programmer if you don't have one). It's really easy to program the chip without going through all the dreadful assembly language. I just don't want to make it into a "work" thingy. Although the code would be more efficient if I use assembly, but for the purpose of this small project, I don't need to care about the code speed, memory locations, blar blar blar.

 

The timing circuitry is really simple, basically the DS1302 saves and count the current time. So all you need to do is to program the SX28 constantly reading the "current time" from DS1302. Once you hit the time you want your lights to turn on, you slowly output PWM signal to the control port of buckpuck, buckpuck will dim/light the LEDs accordingly. That's about it.

 

Btw, my original code did incorporate a 4x20 LCD screen with it. The LCD showed all the current time and date and show when the lights is on/off, a lot of cool features. But I took the LCD and all the codes off becuase I don't want to add more cost to the setup, coz you know, it's only for an 8G...

 

evilc66, the "brain" is finished and ready to go, I can upload some of those pictures tonight. I am still cutting and trimming the AL heatsink, I was trying to cut the Al last night using a hack saw, big mistake... but I don't want to wake up the neighbours by firing up the machines, oh well. I will try to finish the whole thing this weekend, but I want to do it in one shot, coz I don't have a spare hood and I don't want the tank to go without light for too long. We'll see.

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ok, I finished the whole thing over the weekend. Let's get straight to the pics:

 

"brain", this pic just showing how I started, basic copper board and I printed out the circuit that I designed:

P9220091.jpg

 

I transfer the toner onto the copper circuit board, and I fixed the circuit here and there using a sharpie:

P9230093.jpg

 

This is after I etch the copper and cleaned the toner and sharpie markings:

P9230096.jpg

 

Solder all the components in place:

P9240099.jpg

 

Bottom of the finished product:

P9240101.jpg

 

The case, basically I used an old computer power supply, gutted it and fit the newly made circuit board into it:

P9250102.jpg

 

And added the 24V AC/DC power supply onto the circuit board that I made, fitted everything perfectly and tightly:

P9250104.jpg

 

This is the finished product with a nice 80mm 24V 47cfm fan, I actually cut up the original oceanic power cord, I like the quick connect plug a lot, so I cut it up and fit it in.

PA030114.jpg

 

Another angle:

PA030115.jpg

 

Finished product with case:

PA030116.jpg

 

Back side:

PA030117.jpg

 

That's about it :)

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Now onto the hood...

 

First, I machine the heat sink into the size I want:

PA020111.jpg

 

Then I drill, tap a lot of holes... put some artic silver in between the layers, and I added 2 40mm 12V 24cfm fans:

PA030118.jpg

 

From the back side:

PA030119.jpg

 

Bottom look:

PA030121.jpg

 

On with modding the hood, gutted it, and I drilled some heat vent:

PA030126.jpg

 

Also modded the original power cord for my likings, the inside look:

PA030128.jpg

 

Then fitted everything in, tight and to the spec:

PA030130.jpg

 

Closer angle:

PA030135.jpg

 

With the cover on, tight spaces, math is everything :)

PA030137.jpg

 

Tested it out:

PA030141.jpg

 

Installed pic:

PA030151.jpg

 

Final running pic:

PA030143.jpg

 

Closer one, yeah I know, my pic skill sucks...

PA030157.jpg

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:bowdown: :bowdown: :bowdown: :bowdown: :bowdown: :bowdown:

 

i need to get my act together and start making my LED light...its not going to be anywhere near as clean as yours =(

 

arent those 40mm high flow rate fan LOUD AS F? i had the 60mm and 80mm versions before...they are load as hell, but boy do they blow!

 

last thing, im interested to see a video of the dimming in the tank. could you take a video of that?

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My impression: everything runs like it should, the hood is cool to touch, barely warm, heat coming out of the vents nicely. Although a bit noisy with all 3 fans, because they are high cfm fans. It's either I choose heating the hood, warping something, possibly over heating or I choose noise. I rather have noise since I am not going to sit next to the tank 24/7.

 

Light dispersed like I estimated it should, a nice trapezoid, doesn't waste any light outside the tank. Color temp is nice, I would guesstimate (my eye meter) that it is around 12k-14k Kelvin, since my 20k MH is a bit bluer then that. It's really bright and crisp, big difference with the OEM CF light before.

 

Now something I really don't like: Since I have BIG water movements at the surface, I have 3 power heads, 400gph, 900gph and 1200gph, so there is nice shimmering effect, BUT, it deflected the blue and white LEDs. That is, the tank seems like having a million strobe light, pulsing between white and blue, shining at random spots. When I turn off the power heads, the light looks perfect, smooth and mixed. So now I have to choose between water movements/waves at the surface, or million of small strobe lights. My gf said she love the looks, so I may stick with the waves at the surface and see how it goes.

 

Overall, I think this is worth it, a nice and fun little project in my spare time. I hope you all like it, enjoy!

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:bowdown: :bowdown: :bowdown: :bowdown: :bowdown: :bowdown:

 

i need to get my act together and start making my LED light...its not going to be anywhere near as clean as yours =(

 

arent those 40mm high flow rate fan LOUD AS F? i had the 60mm and 80mm versions before...they are load as hell, but boy do they blow!

 

last thing, im interested to see a video of the dimming in the tank. could you take a video of that?

 

Thank you, and yes, those fan are loud... I need the CFM to move the heat, it's sitting next to the TV, and we have the TV on pretty loud anyways, I am sure we will get used to it.

 

I will make some kind of final video, but I dim/light the tank over an hour of time. I can code a test program and maybe make a video of it over the tank in 2-3 min. Maybe tomorrow, I will see what I can do.

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Thank you, and yes, those fan are loud... I need the CFM to move the heat, it's sitting next to the TV, and we have the TV on pretty loud anyways, I am sure we will get used to it.

 

I will make some kind of final video, but I dim/light the tank over an hour of time. I can code a test program and maybe make a video of it over the tank in 2-3 min. Maybe tomorrow, I will see what I can do.

 

hey..im free tomorrow..i can sit here and watch an hour long vid :D

 

if your camera has time laps function that would work too =)

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Thanks Tbone675 :)

 

And disaster999, I don't think my camera has time laps function, I mean just look at the crappy pics I took, half of it is because my skills, the half is because of the crappy camera :D

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