DIY LEDs - The write-up

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"24 Cree White LEDs mounted on star boards"

I bought every type of LED in this format i could find and Cree was the best choice.
If you look at the picture, it has several different vendors LEDs
The Luxeon did not seem as bright and was almost impossible to solder.
 
For those of you considering alternate power sources, if it self-regulates or you add a regulator to it to get the voltage that matches your string of LEDs, then great.

If not, if you need to curb your power supply, remember that you can put a small current sensing resistor in the middle of the string of LEDs (another adaptable beauty of Soundwave's design!), instead of on the top or bottom. This means an inexpensive op-amp can be used for reading the sense resistor instead of the hugely expensive rail-to-rail op-amps required for high-side or low-side current sensing. With an appropriate reference voltage, the op-amp can drive the gate of a VFET on the low-side of the LED string to limit the current. The closer the power supply is to the required voltage, the less is wasted in the VFET (but it needs enough voltage to go across all the LEDs, the sense resister and the VFET).

Then, instead of a fixed reference voltage, by controlling the reference voltage to the op-amp, you get dimming function. With a driver circuit for the reference voltage that cycles it, you can get what every on/off pulse cycle you desire, reduce energy use, extend life of LEDs, sync to your stereo bass beat...
No. Bad Canoe. Baaad Canoe.
 
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As for laptop power supply, you really recommend them?

With my design and other DIY designs, I don't have enough
lifetime data to recommend them. It is a power supply used
to provide 65 watts at 18.5 volts for laptops so it does have
a past history of success in a different application. I know this
is somewhat of a disclaimer but without more data I would not
recommend or not recommend either power supply.

At this point, I am looking for feedback on this solution compared to others.
 
The laptop power supplies do work but you're right, their intended purpose is not what they are being used for. Using a true power supply like the ones I linked to at mpja.com are far more reliable and are meant to supply power for long periods.
 
"The laptop power supplies do work but you're right, their intended purpose is not what they are being used for."
I think a laptop will be okay long term.
I think it is an acceptable use. I just don't have the data to confirm. The price your vendor list is very good so this decision is mostly preference. I don't like the open case on the supply you purchase, do you enclose it for protection from salt water?
The are also systems that provide high current at a low voltage that may be more reliable parallel source. Has anyone looked at these? These DIY led system get better all the time. Your design
is the best I seen so far.

http://www.dealextreme.com/details.dx/sku.11809

http://www.dealextreme.com/products.dx/category.917~search.current
 
I keep the power supplies in a box that I made with fans keeping them cool. The box is under an end table that sits next to the tank. I do need to add a cowl or something to the assembly as I have cats, as well. I can only imagine the sound I would hear if one of them put their curious paw in the fan while its spinning. I have a lot of plexi sitting around so I'll probably improvise something with that.

Thank you for the design comment, by the way.

powersupply.jpg
 
I am in the process of setting up my 280, and was considering going with a led set up similar to Soundwaves. My tank is 72x30x30 so I was going to make three setups for each opening in my euro brace. Just like Soundwaves, but I would use two 3x6 led rows on each heat sink for a total of 36 per opening. My question is will that be enough light or should I use two 4x6 led rows per opening? The tank will be 80%LPS 20% SPS. Also if you use the buckpucks with the dimmer can you connect the pots together to dim multiple units at once?
 
<a href=showthread.php?s=&postid=14561703#post14561703 target=_blank>Originally posted</a> by Keith Elliott
I am in the process of setting up my 280, and was considering going with a led set up similar to Soundwaves. My tank is 72x30x30 so I was going to make three setups for each opening in my euro brace. Just like Soundwaves, but I would use two 3x6 led rows on each heat sink for a total of 36 per opening. My question is will that be enough light or should I use two 4x6 led rows per opening? The tank will be 80%LPS 20% SPS. Also if you use the buckpucks with the dimmer can you connect the pots together to dim multiple units at once?
Click to expand...

Hey Keith,

I am going to be setting up a tank of similar dimensions 72x24x31. I have posed this question to Evilc66 over on nano-reef dot com. He seems to think that will not provide enough light if you are going to want clams down on the sand bed. You will need to decrease spacing between LEDs and use optics to increase PAR values lower in the tank (would be like a 400w MH equivelent).

He is going to run the numbers of how many LEDs to reach that for me, but has not gotten to it yet. Why don't you pose the same question over there and maybe he will finally run those numbers :)
 
You have an odd case, Keith. With such a deep tank, you might need optics to get the PAR needed for the amount of SPS you want to keep. That being said, you will probably need to use at least the 4x6 idea. I got some optics from a friend and they cut the pattern way down. Much brighter, though.
 
<a href=showthread.php?s=&postid=14562277#post14562277 target=_blank>Originally posted</a> by Soundwave
You have an odd case, Keith. With such a deep tank, you might need optics to get the PAR needed for the amount of SPS you want to keep. That being said, you will probably need to use at least the 4x6 idea. I got some optics from a friend and they cut the pattern way down. Much brighter, though.
Click to expand...

Lol, typing at the same time :)
 
Deal Extreme carries E27 Base Cree 10w lamps, could you wire 4 this together along with some 3w blue leds to make a small pendant? I have a 48 L x 24 w x 18 H tank so I'm thinking 2 or 3 pendants?
 
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<a href=showthread.php?s=&postid=14557188#post14557188 target=_blank>Originally posted</a> by ME2003
"24 Cree White LEDs mounted on star boards"

I bought every type of LED in this format i could find and Cree was the best choice.
If you look at the picture, it has several different vendors LEDs
The Luxeon did not seem as bright and was almost impossible to solder.
Click to expand...


That's not true the lumen output is the same if not better...... They are small and hard to solder though. And they are cheaper...
 
<a href=showthread.php?s=&postid=14562276#post14562276 target=_blank>Originally posted</a> by KKamy
Hey Keith,

I am going to be setting up a tank of similar dimensions 72x24x31. I have posed this question to Evilc66 over on nano-reef dot com. He seems to think that will not provide enough light if you are going to want clams down on the sand bed. You will need to decrease spacing between LEDs and use optics to increase PAR values lower in the tank (would be like a 400w MH equivelent).

He is going to run the numbers of how many LEDs to reach that for me, but has not gotten to it yet. Why don't you pose the same question over there and maybe he will finally run those numbers :)
Click to expand...

If you look at the commerial units (Solaris) for 72" length they use
180 Leds. I really think soundwave is using way to few LEDs in his design. He needs to double what he has to get decent PAR. I also hope that people realize the light must be placed very close to the water to work without optics. I would like to see someone else take some PAR readings on this before anyone goes out and builds this they might be a little dissapointed
 
This is a great thread soundwave....and you are one patient dude...lol...After reading this and looking at your design this is the first time I've ever considered LED. I think this would work great for a school AIO tank we have that is running just two 18w pcs I think. I'm gonna be doing a ton more searching and reading on my own but if anyone has any ideas or can point me in the right direction (i.e. links...) it would be greatly appreciated! Thanks
 
I went comercial ang bought 3 current powerbright led setups 1 in 10k and 2 50/50s and i am very happy with them. I only have a total of 12 leds over my tank (24g nano) and everything seems to be doing fine, i have some polyps in my sand bed and the tanks 19" deep. Soundwave do you think i need to add more? I have pictures in the nano thread under "pc convert to led". If you have the time check it out and let me know what you think.
 
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