DIY LEDs - The write-up

[akindbro4u]

I emailed Joni on wed, and Mark yesterday, and still no response. I really want to know what is on back order, because if it will be in soon I may up my order.

just realized if i emailed mark yesterday my time it would have been sat there time. don't know if they are open sat. but joni would have got the email on Thursday.

 

[TheFishMan65]

I have done some testing with my heat sink. I mounted one LED on the bottom (flat side) and then tried with one LED mounted between 2 side slits. I could measure no difference in the runnng temperature. I think I will use them as is. I can also mount my drive board to the side (above the slots) and that should allow better cooling of the driver. The three holes that run through the extrusion will also allow for great mounting. Drill a few holed and I can tip the LED angle by only unscrewing 4 screws (2 at each end).

 

[der_wille_zur_macht]

Any thoughts?

Ask on the flashlight forums. :lol:

My primary concern in a flashlight or headlamp would be cooling. The XP-G's max current rating has gone up at least twice since it was released so the vendors you're looking at probably just have outdated information. Still though, even if it can handle 1.5A, it won't be making twice as much light as much light as at 750mA, but it'll be making more than twice as much heat - relative efficiency decreases as current goes up.

Despite being off topic I hope you post back some results. I'm thinking of doing a bike light with an XP-G so I'd like to see how your conversion turns out.

 

[tahiriqbal]

I think its about time that I should introduce my DIY touch screen controller along with 4 x 48Volt PCB driver to run 40 high power 3 watt LEDs. OK... Most of you would ask me for the details and pictures and I think it would only be fair to start a new thread.

Project is predominantly done to see the capabilities of the driver board and how I could employ a touch screen controller to make it easy and more versatile to suit reef aquarium hobby.

Future plan:-

I have already designed few new PCB driver boards which would have space for LEDs 10 x Cree XP-G and 10 x Cree's XP-E layout. This is much better way to approach the LED lighting fixture since it will save space, less wiring, much better control for dimming etc. I have also looked into Grim's thoughts regarding using lower kelvin rating LEDs in XP-G format, maybe between 5000K to 6500K and see how they look.
Will get my Nikon fired up tomorrow and let you all peep though this DIY project.

 

[widmer]

Ask on the flashlight forums. :lol:

My primary concern in a flashlight or headlamp would be cooling. The XP-G's max current rating has gone up at least twice since it was released so the vendors you're looking at probably just have outdated information. Still though, even if it can handle 1.5A, it won't be making twice as much light as much light as at 750mA, but it'll be making more than twice as much heat - relative efficiency decreases as current goes up.

Despite being off topic I hope you post back some results. I'm thinking of doing a bike light with an XP-G so I'd like to see how your conversion turns out.

LOL I ended up posting there.. They get extremely technical with their flashlight jargon over there. As far as the XP-G's overheating, what's fun is that even these two-dollar drivers from dealextreme have a thermal shutdown thing.

But I was thinking if I can get like a 1/4" thick puck of aluminum to mount the LEDs on, and then have it snug up against the (aluminum) body of the flashlight with thermal paste, the entire flashlight should basically be a heat sink in case there ever is a reason to run the flashlight for more than a few minutes at a time.

Really looking forward to breathing new life into these super cool antique flashlights from the '40s. If I calculate correctly, 3 of the XP-G's are going to make it ~half as bright as the average car's headlight..

 

[SpacedCowboy]

I think its about time that I should introduce my DIY touch screen controller along with 4 x 48Volt PCB driver to run 40 high power 3 watt LEDs. OK... Most of you would ask me for the details and pictures and I think it would only be fair to start a new thread.

Interesting. I too have been designing a touch-screen controller for my modular USB-based system.I'm currently trying to decide between a 3.5" (240x320 resolution) and 7" (800x480 resolution) screen... The 3.5" screen is a lot cheaper, and probably good enough, but it's hard to control the lust once you've played with the 7" one

Simon.

 

[BeanAnimal]

I have used this 320x240 on a few of my Atmega128 projects. The problem with going bigger is the system resources (memory, stack, etc) needed to store the custom graphics, etc and/or the codespace required to draw custom screens that large on the fly.

http://ledsee.com/index.php?page=sh...ategory_id=23&option=com_virtuemart&Itemid=27

I have been looking for a good inexpensive 800x480 or similar screen that has a simple 4 wire touch interface like the product I linked to above. The problem I have found is that screens that large have oddball driver boards and interfaces as well as being very expensive.

 

[deral]

Why in US nobody can manufacture LED aquarium lights? Can you sell them if they are import?

 

[The Grim Reefer]

Why in US nobody can manufacture LED aquarium lights? Can you sell them if they are import?

If you do anything but a basic light you will have to deal with the patent holder of using an LED with integrated controller. So far AquaIlluminations is the only one doing it under license from the patent holder.

 

[The Grim Reefer]

Anyone use the adhesive epoxy? I was wondering how many starts a 2.5 gram tube of the stuff (Arctic Alumina) will glue

Thanks

 

[tahiriqbal]

Anyone use the adhesive epoxy? I was wondering how many starts a 2.5 gram tube of the stuff (Arctic Alumina) will glue

Thanks

I think you be better with using thermal tape, much better and saves you messing about.... fleebay item number @ great price and up your creek too...

Will be uploading my new thread on touch screen controller in next few hours. I hope to see you all there and look forward to have some feedback.

 

[serpentman]

Well.. I understand the hesitancy but if you'd read all zillion pages of the DIY LED builds you'll see that LEDs can blow MHs out of the water in PAR. You can get PARs vastly higher than MH can produce. In fact it's becoming clear that you can easily over-light corals if you're not careful. We are finding that you should use the dimming abilities of LED drivers to work up the brightness, over many days, to prevent bleaching. LEDs are the only viable way to punch to the bottom of deep tanks. The optics allow beam collimations that can hang together for greater depths than are available with MH's point source.

But one of the real beauties of LED is that with a deeper tank you actually control the light placement. You could run different optics or a higher number of LEDs focused on the deeper regions while running wider or fewer LEDs directed at the shallower areas. (Something completely lacking in MH's ability.)

I'm sure careful planning and use of LEDs would allow you to probably drop your system's electrical bill to something around 1/4 of MH's.

Let me try to list the saving paths:
1) You get the approximately 50% straight off.
2) You can light specifically and hence not over-light.
3) You can run dawn/dusk profiles.
4) Almost no IR is projected into the water.
5) Chiller or A/C loads will drop substantially.
6) If you are billed in tiers then the saved kWhrs can be the most expensive ones you are normally paying for.

As for initial expenditure der has run down the payback several times. Yes! Up front costs are steep, but the payback hovers around 1.5 years. Any business would fall all over itself for that kind of payback.

T'wer me? I'd be building LEDs then sell your MHs while they're still in good shape and others haven't seen the light. Cashing in on your MHs would probably slash your payback period to just months. :dance:

This is definitely going to be my migration plan. However, before I invest the $ for everything, I would start with replacing my VHO's.

Do you think running 24 royal blue across the front and 18 across the back will give me adequate supplementation with MH's?

Tank is 72"L x 36"W x 27"H

 

[tahiriqbal]

Now!!!! Can be seen on.......

http://www.reefcentral.com/forums/showthread.php?t=1823278

 

[Reef_Matrix29]

Anyone use the adhesive epoxy? I was wondering how many starts a 2.5 gram tube of the stuff (Arctic Alumina) will glue

Thanks

I have a 4 gram sized tube (half of pen length) and was able to do 72 stars with a little left over. I've seen the tiny ones that Radioshack sales, but that wouldn't be cost effective for me, so I picked up some from a computer parts manufacturer in a bigger size.

 

[nitjt]

Is most everyone going with thermal tape or epoxy when it comes to sticking the LEDs to the heat sink? How hard is to remove the LED from the heat sink if one LED goes bad? I hate the idea of drilling a bunch of holes and screw'n the LEDs down but if I need to replace or change some LEDs down the road I don't want a big hassle trying to get the epoxy off the heat sink. What size stainless steel screws should I use one smaller XP-G LEDS?

 

[Neogenocide]

I used nylon screws to fasten my led's down. They work great and aern't conductive!!! Cheap to boot, 50 pack for $2.50 I found that 6-32 x 1/2" worked well for this application.

Scott

 

[hlsooner]

Anyone use the adhesive epoxy? I was wondering how many starts a 2.5 gram tube of the stuff (Arctic Alumina) will glue

Thanks

I used the Arctic Silver epoxy on 150 of the 10mm boards. It takes very little for each LED and they are they are not coming off when it dries. It cures fast, so I mixed up enough to do about 10 at a time, otherwise it hardened and got wasted. I used two of the 7 gram tubes to do my entire batch.

If you look at the thermal conductivity of the Arctic Silver epoxy versus the thermal pads or any of the other thermal adhesive tapes I found, the Arctic Silver epoxy is many times better.

As a rough lay estimate, I had an area of my heat sink where some of the Arctic Silver epoxy got smeared. I touched it with my finger after it dried, and it actually felt cooler (indicating rapid heat conduction) than touching the polished aluminum heat sink itself.

 

[Skeptic_07]

another trick is to just put small dabs of each part of the epoxy where you intend to glue each star, then when you are ready to glue them down use that little spatula that they give you or a pen cap etc.. to mix the dabs together and put the star down. Pay attention though because they will move a bit before the glue dries. be careful squeezing out tiny amounts though, sometimes the 'white' color part comes out of the tube FAST! I was able to do roughly 80 stars with one pair of tubes.

 

[skippyreef]

what are you guys using to test the LED's to make sure they work prior to using them????? Once they are down with the epoxy my understanding is it is forever.

 

[shackscs]

what are you guys using to test the LED's to make sure they work prior to using them????? Once they are down with the epoxy my understanding is it is forever.

Not forever, but it will take some work to get them up. The other problem I see is making sure that you get it all up so that the heatsink is nice and smooth for the next LED.

I used the thermal tape because I had it but purchased two tubes of the thermal adhesive for the rest of my build.

As for testing, I used two 1.5v AA batteries in a holder with alligrator clips to test each of the LEDS before wiring. And yes you definately want to test them prior to adhereing them to the heatsink.