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-   -   DIY LED Fixture for 7 Gal (w/ pics) (http://www.plantedtank.net/forums/showthread.php?t=85622)

Temuchin 04-07-2009 10:44 PM

DIY LED Fixture for 7 Gal (w/ pics)
 
I've had a LED fixture in the works for several months. I had the time to look through the forum here yesterday and realized several others are done with or part way through the process as well.

Hoppy
Malaybiswas
Kev82

The following is my work so far along with some comparison pictures. Once fully completed I will follow up with more pictures and a parts list.

First of all, why am I doing this? I wanted to replace a 16 inch florescent fixture. With the exception of Catalina Aquarium, no one makes stock lights in this width. Thus, time to DIY it. When it comes to the question of florescent vs LED, LED wins because its way cooler, more fun to build, and the parts came at little to no cost to me. Without that last one I would have built my own 18 W compact florescent fixture due to the cost. Either way this fixture will need to fit into the plastic housing the old light came in.

Design questions? How many LED do you need? I gave up on trying to figure this out. There is not enough information to easily compare wattage on PC bulb to lumens from a LED array. In my opinion the problems comes in that lumens out of a PC bulb is measure in a way that collects light from all directions and directs it to a detector. This is not how we use PC bulbs in an aquarium though. A good reflector still has some loss in addition to light spilling out of the tank and restrike to the bulb. So you can compare diffrenet types of florescent bulbs but there are some assumptions that break down the comparison when moving to LED's. Light from a LED does not need to be reflected, and comparing power consumption (watts) breaks down because LED are more energy efficient.

In the end I just guessed how many LED's to get. I settled on 10 6500K 1W LED's at 55 lm each. I added 3 blue 1W LED at 11 lm each. The blue were to serve as a moon light but I am rethinking that now. More on that later.

Constant current Led drivers are the way to go. No need for resistors, they are flexible in terms of the number of LED's they can drive, are dimmable on the fly and if you blow a led to an open circuit the driver still supplies the same current. I am driving these LED's with 2 LuxDrive Boost pucks.

Now to some pictures. Forgive the soldering, I'm a chemist not an electrical engineer.

13" extruded Heatsink. These LEDs generate a fair bit of heat. Over the course of an hour the heatsink will become warm to the touch. When installed in the housing there will be two small fans moving air across this.
http://www.jasonandavie.com/Aquarium..._MG_6197_s.jpg

The business side
http://www.jasonandavie.com/Aquarium..._MG_6196_s.jpg

The LEDs are arranged (from left to right) a blue led, a cluster of 5 white, another blue, another cluster of 5 white and then a final blue. Each color is arranged in series 3 and 10 LED's long respectively.
http://www.jasonandavie.com/Aquarium..._MG_6195_s.jpg

Temuchin 04-07-2009 11:06 PM

Though not done yet I think I have taken a different enough plan from the others listed before that I have some thing to add here.

Hoppy was discussing PAR comparisons in an earlier thread. I don't have a PAR meter but I do have a nice digital SLR camera. This allows for somewhat of a qualitative comparison. The following images are all taken with the same shutter speed and aperture setting. The difference in light intensities between images accuratly portrays the difference in lighting conditions.

First in my 14 Gal bio cube. This tank is being set up this week. It is not the final destination for this LED fixture. It has a 24 W 6700K PC bulb that is brand new and a 24 W 10000K PC bulb that is about a year old.

Both bulbs
http://www.jasonandavie.com/Aquarium..._MG_6187_s.jpg

6700 bulb
http://www.jasonandavie.com/Aquarium..._MG_6186_s.jpg

10,000K bulb
http://www.jasonandavie.com/Aquarium..._MG_6185_s.jpg

Led Fixture
http://www.jasonandavie.com/Aquarium..._MG_6183_s.jpg




Now on to the tank this light will be used on. This standard light here is a 6700K 14 W florescent tube light, but it is over 2 years old.

Old light
http://www.jasonandavie.com/Aquarium..._MG_6194_s.jpg

Led Fixture
http://www.jasonandavie.com/Aquarium..._MG_6190_s.jpg

Just White
http://www.jasonandavie.com/Aquarium..._MG_6191_s.jpg

Just Blue
http://www.jasonandavie.com/Aquarium..._MG_6192_s.jpg

CL 04-07-2009 11:10 PM

Very nice build. It seems that leds are really becoming popular!

kev82 04-08-2009 01:03 AM

I'm looking forward to see some growth results from this... I like how you put your leds together nice and tight :)

malaybiswas 04-08-2009 02:21 AM

Nice job. Good to see other fellow diy led enthusiasts.

10 1w is more than enough although the visible difference does necessarily equate to PAR differences.

I was about to say that 3 blue moonlight is not necessary for 7 gals but you already done it and it looks nice.

Regloh 04-08-2009 03:38 AM

This is very nice.. you guys are slowly convincing me that I need to put an LED light fixture onto my todo list ;)

I also would like to see how plants react to LED's in general.

Wicket_lfe 04-08-2009 01:52 PM

That is awesome. If you did buy the parts do you have a guesstimate of the approximate cost? I want to do this with a 2.5 gallon, so i would only need a few leds.

purplecity 04-08-2009 09:26 PM

can u please tell us how much all the materials cost you roughly and where you got them from?

i am very intrested in making two light fixtures for my 10 gal's
how many watts/leds would you recommend for a 10 gal

Cactus Bastard 04-09-2009 04:44 AM

Good job here, I'll be watching this one.
You added some blue LEDs, originally intending on using them as night lights but mentioned you were re-considering that? I'm assuming you noticed how much of their energy plants derive from the blue spectrum. Have you looked into imbalances that may occur from the lack of equally heavy 650 - 700nm lighting?

Temuchin 04-09-2009 09:43 PM

Parts List (Yeah for Google Doc's)
http://spreadsheets.google.com/pub?k...Hl7hrT8zoxAXVw

Total cost was ~$230. This is way more expensive then what it would take to build an equivalent PC fluorescent lamp

Quote:

I'm assuming you noticed how much of their energy plants derive from the blue spectrum. Have you looked into imbalances that may occur from the lack of equally heavy 650 - 700nm lighting?
I'm not a plant biologist, but yes plants are typically efficient at converting blue light, with an average peak at about 420 nm. (The blue I used is at 460 nm.)

In researching my plan for the light I came across message boards for people growing hydroponic plants (tomatoes). While it is might be more efficient to use a spectrum of light, these people showed that plants can be grown with just Blue and/or Red LED's. That said, it will be very interesting to see what plants do well and if others do even better as all plants have a different spectral response. When I plant this tank I will have to focus on as many different colors as I can pack into such a small tank.

Quote:

I was about to say that 3 blue moonlight is not necessary for 7 gals but you already done it and it looks nice.
My plan was not well thought out regarding these blue lights. The second I powered them up I realized that even dimmed down, they would be too bright for a moon light. I am now thinking I will just use them as part of the normal day time light. I would love access to a PAR meter to measure their impact directly. Thats the problem with lumens though. An 11 lumen blue LED has a lot more photons available for photosynthesis then an 11 lumen green or even an 11 lumen white LED.

Hoppy 04-09-2009 10:21 PM

I keep forgetting to ask this: what kind of heatsink is that? It looks like a surplus electronic device sink of some kind. And, of course, what does it cost?

purplecity 04-10-2009 01:24 AM

lol, wow i always thought DIY's were for people on low budget guess not lol
anyway i dont think i can do it myself with that kind of prices lol

Hoppy 04-10-2009 03:41 AM

Quote:

Originally Posted by purplecity (Post 826002)
lol, wow i always thought DIY's were for people on low budget guess not lol
anyway i don't think i can do it myself with that kind of prices lol

It doesn't have to cost that much. You can do fine with a standard DC power supply, and current limiting resistors. That can save a big bundle. My local surplus electronic equipment store has DC supplies, wall warts, and others, by the hundreds, in many voltage ratings, and most for about $7 max. Resistors aren't expensive either, also being available at the surplus store. Cooling fans, in all sizes, are about $5 each at that store. (If I had found that store earlier my cost for a light for my 45 gallon tank would be around $125 total.)

purplecity 04-10-2009 07:04 AM

I have two 10 gal's that are in dire need of lighting I was guna go down to homedepot and pickup a light fixture or something i dont know what to do,

hoppy how much do you think it would cost to make 2 of them?
i like these leds because theyr so sleek and small and i heard its possible to attach a dimmer to the leds, that will be so amazng omg:thumbsup:




Quote:

Originally Posted by Hoppy (Post 826137)
It doesn't have to cost that much. You can do fine with a standard DC power supply, and current limiting resistors. That can save a big bundle. My local surplus electronic equipment store has DC supplies, wall warts, and others, by the hundreds, in many voltage ratings, and most for about $7 max. Resistors aren't expensive either, also being available at the surplus store. Cooling fans, in all sizes, are about $5 each at that store. (If I had found that store earlier my cost for a light for my 45 gallon tank would be around $125 total.)


Regloh 04-10-2009 12:46 PM

Quote:

Originally Posted by Hoppy (Post 826137)
It doesn't have to cost that much. You can do fine with a standard DC power supply, and current limiting resistors. That can save a big bundle. My local surplus electronic equipment store has DC supplies, wall warts, and others, by the hundreds, in many voltage ratings, and most for about $7 max. Resistors aren't expensive either, also being available at the surplus store. Cooling fans, in all sizes, are about $5 each at that store. (If I had found that store earlier my cost for a light for my 45 gallon tank would be around $125 total.)

Another resource for cheap electronic equipment is this:
http://www.mpja.com


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