DIY LEDs - The write-up

[widmer]

I'm not widmer but I have several of the same power supply. It has two sets of output terminals, hence the total of 7.

Bingo. And if you look at the board, both sets of +/- are directly connected without any goofy electronics connected between them that I wouldn't understand.

Thanks for trying to help solve the capacitor conundrum Stu. I've come to terms with putting the power supply in the air though, and actually am thinking it's best this way now regardless.

 

[jdrabek]

Yes, that's great! Thanks!!!

I need a little clarification though.

1. Do the meanwells convert from AC to DC. Is that why you don't need a power supply?

2. The controller (Profilux in my case) is not actually providing power to the LEDs, right? It just provides a signal or enough voltage (0-10V) to "tell" the meanwell drivers how much to output, correct?

3. Has anyone done any PAR readings with and without an acrylic cover. I'm just surprised widmer didn't extend that acrylic to cover the LEDs. I wouldn't think an acrylic cover would significantly impair output.

I just fiished my blue LED's last week hooking them up to my Profilux. Dont forget that if you want to dim you will need to get the EVG board from Profilux.

 

[wolmutt]

Interesting read. I would love to do this, but its way over my head.

 

[stealle]

Where is the best place to buy LEDs?

Is the Cree XP-G LED available to the general public yet?

Does a good 3W UV-A LED exist?

 

[MontyJack]

I just fiished my blue LED's last week hooking them up to my Profilux. Dont forget that if you want to dim you will need to get the EVG board from Profilux.

The EVG-AP board from GHL is not really necessary. If you know the layout of the light controlling plug you can do what you want with the signal coming out there. There is one lead with 12-15V uncontrolled, than 2 leads dimming, and 2 leads to control the relays on the EVG-AP board and one lead with the ground. So you can crimp your own stuff in a western plug and hook them up to your PL. Just make for sure you’re not blowing it up.

The layout is here: http://www.aqua-it.de/vb/attachment.php?attachmentid=275&d=1191412298
...but in German.

A good point to use the board is that the controller switchs off the relays after the dimming period and the drivers are cut off from the electric supply when they’re not in use. Of course if they’re also hooked up to the main power on the board and not just with the dimming leads.

Monty

 

[kcress]

Where is the best place to buy LEDs?

??

Is the Cree XP-G LED available to the general public yet?

Yes. Several here have bought them.

Does a good 3W UV-A LED exist?

No. And if it did you would be hard pressed to get one due to the high danger it would pose to non-technical users. When low power UV LEDs came out a designer had to sign papers and demonstrate commercial usage.

 

[Skeptic_07]

Is the Cree XP-G LED available to the general public yet?

yes, cutter.com.au has them and are actually offering free shipping to the US until the end of the month IIRC.

 

[der_wille_zur_macht]

There is (or recently was, I don't know what the end date is) a group buy for XP-G on the nano reef forums. Also, ETG has them, or at least can get them on short notice.

 

[widmer]

Update:

Well I was hoping to have the fixture hanging by the end of the weekend, alas sometimes I think faster than I move. Anyways, last night I got the LEDs mounted with arctic silver premium thermal adhesive. This is a two-part adhesive which only gives ~5 minutes work time before it solidifies. So it was a little stressful. Nevertheless, I would say they turned out pretty elegant bearing in mind that I was using no measuring devices to space and align the LEDs:

All that's left now is to wire the connections. I think I'm going to pick up some bare rosin to brush the LED terminals before soldering, so that I'm not burning out the LEDs trying to get rosin-core solder to adhere. Good plan?

 

[L98-Z]

What made you go with the adhesive Widmer? I was thinking about going that route, but I fear having an LED burn out and trying to get it off the heatsink.

 

[widmer]

Several reasons for me:

1. It's easy, fast & cheap
2. I saw how much people were struggling with drilling and tapping holes
3. All of my projects take place in my living room/kitchen :lolspin: and my tool collection is very limited
4. I tested all LEDs beforehand to make sure they work, and their estimated lifetime is much longer than I plan on being interested in this fixture (ie 10 years for them, 3 years(?) for me)
5. With 18 LEDs spread across 2 separate heatsinks, I don't have a whole lot at stake

EDIT: lol @ how fast it is by necessity, the thermal epoxy hardens within 5 minutes of mixing so that tells you how quickly I got it done...

 

[L98-Z]

I see. I don't know how long I'll use them either, but I did have a concern with replacing them. I know I could mill them off, but I hate having to tear everything down and carrying it to a mill to rip a failed LED off.

My project is taking place in my dining room so I can relate.

 

[widmer]

That's certainly a valid concern. And I know that PFO really kind of created a reputation for LEDs being unreliable due to their fixtures failing nonstop, but so far I haven't heard of a single case of an LED failing on here in the DIY fixtures that folks have been making for a couple of years. Furthermore, I forget who it was, but someone on here recently mentioned that they have taken apart a number of the Solaris fixtures, and found that there was a high degree of hodge-podge random bins of LEDs etc in them, so I don't know if this says anything about the quality of craftsmanship having an impact on their reliability...

 

[sbleile]

Widmer,

Once you fire up your fixture would you let me know how warm the heat sinks get? I am considering "borrowing" your idea for making a large fixture, rather then having 6ft long heat sinks.

 

[der_wille_zur_macht]

You guys need to make buddies with someone who owns a drill press. :lol: I'm sure you're both on top of this, but for the sake of anyone else reading the thread and considering tape or epoxy adhesives, use a small amount and apply plenty of pressure (to the star, not the LED itself) for best heat transfer properties.

 

[L98-Z]

You guys need to make buddies with someone who owns a drill press. :lol: I'm sure you're both on top of this, but for the sake of anyone else reading the thread and considering tape or epoxy adhesives, use a small amount and apply plenty of pressure (to the star, not the LED itself) for best heat transfer properties.

A mill will do the same as a drill press, but I know a person who owns both. Just tedious to have to rely on others, I hate doing that.

 

[Neogenocide]

You just have to hide the cost of a drill press into the costs of the fixture when getting approval from out better halves. That's how I do it anyway, and now I've got a pretty good set of tools to work with.

 

[widmer]

You just have to hide the cost of a drill press into the costs of the fixture when getting approval from out better halves. That's how I do it anyway, and now I've got a pretty good set of tools to work with.

I like this...Next time we need to hang a picture on the wall I'll be sure to let my better half know that it will turn out better if we get a drill press to assist. :lol:

 

[der_wille_zur_macht]

YES! The best results are obtained by multitasking and mixing in their desires. For instance, I used my drill press on Saturday to mount bindings on my wife's new skis. I was sure to remind her what the shop would have charged for that service, and how it would have been impossible if not for the drill press.

 

[widmer]

Widmer,

Once you fire up your fixture would you let me know how warm the heat sinks get? I am considering "borrowing" your idea for making a large fixture, rather then having 6ft long heat sinks.

You bet. Watch out for the build thread I'll put up this week if it lights up when I plug it in :lmao:.

On that note, does anyone want to USPS me a PAR meter so I'll have numbers for you guys when the fixture is on the ceiling?