DIY LED light idea

[O2surplus]

So, an electrical storm knocked out a few of the fluorescent fixtures on my 125g... perfect time to upgrade!!

I want LED's. You can't beat the operating cost and the shimmer effect is amazing. The only downside is the initial cost, solution: DIY.

So here we go, my fixture will be made of two punched & formed aluminum parts. Currently the design has 117 10mm LED lamps: 50 6,500k, 50 10,000k, 17 470nm blue. Each lamp has 5 chips and produces 285,000 mcd at 40 degrees running on 100mA and 3.4v. That's 107 lumens per lamp for a total of 12,519 lumens. Not bad considering the Cree 3W lamps put out 107 lumens on 350mA, and cost literally 10x more! I'm going to build my own driver with solid state relays and an Arduino microcontroller. This way I can dim the LED's with a PWM signal. Also I will be able to write the software to control the light schemes and timing, no more instant sunrise! I'm also going to add switches and pots to allow manual control. Cooling via 2 120mm fans, also controlled by the Arduino with a temp sensor. I think I can run the entire thing on about 55 watts with all the lamps on.

Here's my first pass at the fixture. You can see the fan and vent cut-outs in the top as well as the switch and pot holes in the side. I still need to add the power port and USB cutouts.

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Top panel:
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Bottom panel:
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End views showing how they fit together and the cutouts
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Over the 125:
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With 40degree beams from each lamp:
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View from below:
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Side:
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I've already started purchasing components, and it looks like the final build cost should be under $300.
Let me know what you think, I appreciate any and all input. Look for the build thread soon!!!

I like the design of your light fixture but I think it's light output will be much less than your math indicates. Here's why- 3.4Vf x 100Ma = .34 watts per LED. 117 x .34 watts = 39.78 watts total for the fixture. That wattage is really low, and combined with the spread of the LEDs over the tank, will only produce a dimly lit aquarium. I can only speak from my own observations though. I currently have a 225 gallon ( 72"x 30"x24" ) illuminated by my own DIY designed lighting system utilizing 90 Cree XR-E Q5's running at 700Ma for a total of 180 watts. I am able to grow plants with the light system that I have ,but the light only shines intensely enough down the middle of the tank. I will have to double the amount of LEDs (to 180) to get the light coverage that I want.
Like you,I also programmed an Arduino to control my lighting. The sunrise/sunset feature is cool.

Good luck on your project and if you have any questions I'll do my best to help.

 

[ITHURTZ]

i made a similar one.. didn't go through all of the light spectrum .. mine was crudely simple... about 8 replacement 1157 LED brake light bulbs (each has 20 leds clear) light.. soldered the bulbs so that they were switchable tail / brake or both .. plenty of light, shimmer as you stated amazing.. so it allowed me to have a low, med, high light settings.. i used a strip of blue led interior trim lights along the light housing for night time use.. wired it with small flat phone cord. installed a 3-way switch(hi med low) and a single switch for blue. it all powered from an old cordless phone charger.. turned out great at a cost of about 50.00. tucked all inside the florescent light housing with still room for the original bulbs to remain. again i am sure it isnt the correct light spectrum but i have no live plants. .. i like your design.. should work well.

pics?

Very Nice! I would love to have a fixture like this. One question though, What is the length? Also once you build it and it turns out good Start making a 8 foot one for my 240 haha, No really let me know how much it would cost and I would love one exactly like yours, If your up to making some extra cash.

x2

 

[adriggsvt]

Looks like someone's been reading reefcentral.... Make sure to give credit where it is due (der_wille_zur_macht and the rest of the gang put a lot of effort into their work). There are some extensive threads with a lot of BRILLIANT information. It's quite a collection of ideas and how-tos written by some very smart people.

So, my thoughts on this project:
- 3w LEDs are probably a better choice for the project. Not necessarily Cree, but maybe a package from Stevesleds.com. 3w penetrate deeper into the water and will ultimately give you a better look. Also, you'll use fewer of them.
- Optics on the end LEDs only spill light outside of the tank. Consider removing optics from the end LEDs or removing them entirely. This will give your tank a better look and avoid light spillage. Light spillage is wasted because it's not illuminating what you're looking for.
- The aluminum plate to which these are attached does not appear to have any fins. While they aren't necessary to transfer heat, they are necessary to direct the heat, and help greatly to pull it from the LEDs. I would consider adding a few inside the fixture. As I'm sure you know (from RC), heatsinkusa.com sells some products that are perfect for this project.
- Also, you may want to consider 2x36" fixtures instead of 1x72". It will give you more flexibility should you have to change, have failure, etc.

Overall, it looks solid. I'm interested in the Arduino controller (I want to build one myself), so I'll be following along. Make sure to post lots of updates!

Actually I had never been on reefcentral, but I think I just found the 55 page sticky you are referring to. After reading a few pages you are right, there is some really good info there. It's going to take me a bit to read it, but thanks for the reference, I had no idea that the saltwater world was using LED's.

You've brought up the toughest decision I had in this concept: fewer high wattage lamps or more lower wattage lamps. Honestly the main reason I went this direction is because most of the LED builds I've seen go the other route. With newer higher output, less expensive cylindrical LED's available, I really think I can get more light, more efficiently this way as compared to the high-power LED's.... if not I'm only out the cost of the lamps. I think you're right on the dual 36" fixtures idea, I'll try to model it tomorrow if I have time, thx for the input!

Arduino's are alot of fun and there's a million things you can do with them, just look on YouTube. I'll post my code when I get to that stage.

 

[ITHURTZ]

use whatever is cheaper to build but gives the same light!

 

[adriggsvt]

I like the design of your light fixture but I think it's light output will be much less than your math indicates. Here's why- 3.4Vf x 100Ma = .34 watts per LED. 117 x .34 watts = 39.78 watts total for the fixture. That wattage is really low, and combined with the spread of the LEDs over the tank, will only produce a dimly lit aquarium. I can only speak from my own observations though. I currently have a 225 gallon ( 72"x 30"x24" ) illuminated by my own DIY designed lighting system utilizing 90 Cree XR-E Q5's running at 700Ma for a total of 180 watts. I am able to grow plants with the light system that I have ,but the light only shines intensely enough down the middle of the tank. I will have to double the amount of LEDs (to 180) to get the light coverage that I want.
Like you,I also programmed an Arduino to control my lighting. The sunrise/sunset feature is cool.

Good luck on your project and if you have any questions I'll do my best to help.

From what I've read, for LED's it's not all about watts. I think my entire fixture will run under 60w (lamps, fans, arduino, loss over resistors, etc.) which means I can run the entire thing on a laptop charger. My math was converting millicandela to lumens for a 40 degree beam. For a 285,000 mcd lamp at 40 deg, the luminous flux is 107.993 lumens. The XR-E Q5's at their nominal forward voltage of 350 mA emit 107 lumens (according to their site). I can't find and data for XR-E's driven at 700mA but I'm sure it's higher.
I really don't know exactly how bright this thing will be, but for $0.40/lamp I can double them up cheaply.
I appreciate your input, let me know if I'm missing something here (light is not my strength when it comes to physics). You'll probably be hearing from me when I start on the software!

 

[O2surplus]

The Cree XR-E's ( Q5 bin ) that I used were rated for 128 lumens per watt, and at the time of purchase, were the brightest available. There are Cree XP-G ( R5 bin ) available now that are 60% brighter than the ones I purchased. The efficiency of LEDs continues to improve with each new model. I don't think the 40 cent LEDs that your going to employ will perform anywhere near as well as a $7.00 Cree XP-G- Even if you used 10 times the number. The effort involved just to wire that many up and provide heat sinking would be horrible, not to mention INEFFICIENT. There are many people around that have been getting into DiYing LEDs and most have realized that there really is no "Free Lunch", when it come to High Power LEDs.

If your interested in seeing how I set up my system, check this out
http://www.monsterfishkeepers.com/forums/showthread.php?t=364010&highlight=leds+glossostigma