Minimalistic multichip DIY LED build

[Lassef]

Ron is no longer in this thread and i will concentrate my efforts to make this happen with option number 1 so now its time for a swedish saying:

När katterna är borta kan råttorna dansa på bordet

You can reach me through the e-post option here on RC

SINCERELY Lasse

Remember the name of the thread

 

[tomservo]

I've been thinking of the compact Cree pcb myself, and then using a reflector and lens to achieve the same effect. The only problem with Crees, are that they do not make a violet, and you would need to design a completely custom pcb to incorporate the different sized emitter from a different company into it.

I think the SiBDI emitters are the same form factor and they make a 410-420, maybe a 420 centerline?

 

[bhazard451]

I think the SiBDI emitters are the same form factor and they make a 410-420, maybe a 420 centerline?

The Semileds chip is my favorite, and it might be the same. I use it in my fixture now, and I like it better than the others I've tried.

It would still need its own channel, unless you wanted to run the Crees at under 700 mah, which I wouldn't desire. The XT-E's take 1300mah like a champ.

 

[jerpa]

we (the designers) reap nothing but the benefit of the chips.

While funding the R&D. So I wasn't the only one beginning to feel that way.

Bean it seems we are attempting to achieve a similar look for our tanks. I have only begun to really explore other DIY options as it has become painfully clear that is the only way to achieve what I want. I was wondering if you would be willing to share more information with me with regards to your plans. Perhaps I could help defer the cost a prototype. I understand if you would like to keep it off line.

 

[BeanAnimal]

I will share anything I have. In fact, we may be able to involve more club members if there is interest.

 

[mr.wilson]

Whose chip is that? Ah Orphek.

See this is why I feel the warmer whites are needed. Notice they have just blue/white chips, but this XP line with added colors is for "better florescence"? Why use green and red separately when you can just incorporate them in with warmer whites?

The multichip in the photo is a three colour channel multichip.

 

[mr.wilson]

Just for clarification. I am not advocating the use of 2 channels of low Kelvin whites anymore. This is the design I'm supporting right now and I'm replacing a Kelvin rating with a description.

1)14000K
2) 420nm
3) A reddish warmer lower Kelvin white
4) 445nm+455 nm
5) 10000K

It would only include one leg of warm white and, unlike most builds, would have two channels of higher Kelvin whites. Remember even a cool white cree only goes up to 8000K. Once i have seen this manufacturers 10k and 14k I may think we need a 20k emitter instead of 14k, or I may think we should include more visible blues. I'm not saying what we want is possible with this design but I also cant say it is not possible.

I'm not trying to bend anyones personal preference, just share some information I have gained from trying different chip mixes. One point that many people miss is that low kelvin emitters are more about a lack of blue, than quantity of red light. Low kelvin whites are essentially green lights. I agree that using a green chip is pointless because there is more than enough in any white chip. Some advocate orange chips, but I haven't come across any scientific reasoning for this. There is a value to red chips, but they are overpowering and can cause bleaching if used in excess. I liked the idea of turquoise chips, but someone in this thread said they didn't offer a nice aesthetic.

Commercially produced fixtures do not always represent the best mix of chips. They are often driven by production cost, convenience, and can fall behind in technology due to production time. People like to see stability in a brand and are scared off by a constant flow of new product releases. On the other hand, gimmick drives sales so we often see new technology that is brought about strictly for market differentiation. An ad for "Crimson Tide" or "Aqua Marine Dream" LEDs will surely boost sales.

I think your mix of 10,000k,14,000k and another white is a good idea. Just make sure your multichip has room for each respective row of phosphors, as the phosphor is wider than the chip row itself.

 

[mr.wilson]

You can not imagine that this could be because I try to explain issues which are difficult and often needs to be qualified in a language that I was not born with. In addition, it is with people who have another native culture than I have.

Sincerely Lasse

You and I are the only ones who speak English here, so perhaps that's why we tend to agree

 

[gtfcniles]

Reefcentral have made it clear by banning ronreef that they don't want this to happen, if you want more information with regards to chip one email lasse, otherwise the discussion is over.

 

[kahkah]

It is a disappointing end to the discussion, it was a really interesting idea and approach to reef lighting that could have been a game changer since it would have possibly gave a better, cheaper, and more flexiable option than what was already available whether it be a DIY fixture or a pre built fixture.

I'm surprised no one had started up a project at kickstarter. Lol

 

[Sonny n Colleen]

I wouldn't necessarily say this is the end of the discussion. As long as we continue to discuss what the "dream mix" of colors on a multi-chip LED should be we should be fine. When the discussion starts polling members to participate in a group buy or support some sort of commercial venture then the discussion has crossed the line.

Please continue the discussion. I have learned more about LEDs from this thread than I could have ever think. I hope it continues.

 

[jerpa]

Reefcentral have made it clear by banning ronreef that they don't want this to happen, if you want more information with regards to chip one email lasse, otherwise the discussion is over.

RC doesn't care if it happens they just wont allow open solicitation/organization on a public forum regardless of profit motive. Also he was not banned he just lost privileges. One way to make sure the thread gets closed is to continue to solicit people to contact others. I'm sure anyone wanting information can figure out who they should contact.

We are more than welcome to discuss our "dream" configuration but if/when someone found a supplier for custom chips it would be wise to distribute any infotmation relating to group purchases privately.

 

[jerpa]

I will share anything I have. In fact, we may be able to involve more club members if there is interest.

If there is interest it would be nice to be able to gather different ideas and viewpoints.

With regards to an MCPCB, is your concern reflowing the diodes yourself, color mixing, cost?

It seems heat management could be handled similar to the other multichips in this thread.

If that is not a huge hurdle then a multichannel MCPCB design may prove more versatile for anybody. I know the cost for the emitters is reduced when bought unmounted but a custom MCPCB isn't cheap either. There is the time involved as well.

I'm assuming adding vias to an FR-4 board increases costs close to an MCPCB, or is this just not feasible with the heat generated by such a dense array?

 

[BeanAnimal]

With single well spaced 3W emitters, FR4 and thermal vias appear to actually be a better choice then MCPCB, as there is no insulating layer between thermal planes.

That said, I am not sure if the density we are talking about could be handled by FR4, thought it would be MUCH cheaper.

My original plan was close, but not "dense" and I simply wanted to avoid the ugly "stars" and get closer spacing. I have never done any hotplate reflowing, but it is fairly straight forward and the results (reported on diy smt sites) are better than the cheap reflow ofens sold on fleebay.

 

[jerpa]

I read an article by Cree regarding PCB performance. With .8mm FR4 with a full copper bottom, 10mm top trace, and 14 unfilled 10mil vias arranged on a 25mil grid and plated with 2oz copper you can achieve a resistance of less than 5 C/W. MCPCB are around 3.8 according to Cree.

That's their recommendation for something that is cost-effective and easily manufacturable.

With regards to reflow I've only read some DIY as well but I'd be willing to give it a shot. How hard can it really be...

 

[JohnnyAirtime]

The gavel has landed... bummer.

Lots of great information lost to the MODs.

 

[BeanAnimal]

Johnny,

I don't see any loss of information here, I simply see the moderators enforcing a policy that is pretty clearly spelled out. The only posts that were removed were those that violated the terms of service with regard to organizing a group buy.

 

[JohnnyAirtime]

Johnny,

I don't see any loss of information here, I simply see the moderators enforcing a policy that is pretty clearly spelled out. The only posts that were removed were those that violated the terms of service with regard to organizing a group buy.

... there was information linked to other websites, forums, eBay, etc.etc. That has all been deleted (from the 6 pages I went back through). It was a great resource to have for those who needed "where to buy" info, which would save keyboard strokes and finding the "right" item. OR for those looking for other ideas not directly related to the OP's post in this forum.

I like knowledge sharing, and linking to other knowledgeable and informative threads "is not allowed" per the quote below.

I understand the rules, but... there's all kinds of other threads on RC with off-site links. I guess they've not been reported or the MODs have just missed them. Or am I just misunderstanding the rules, or last line item posted by DC?

I've removed a couple posts.

A couple points here:

This is not a selling forum

Group buys can only be held in local club forums

Soliciting unwanted pm's is not allowed

Directing people to another website is not allowed

 

[dc]

If there was an offsite link that had information pertaining to the thread it would possibly be allowed, unless the poster is directing traffic to a site they are affiliated with or conducting a sale. There are also censored sites, that should be easy to figure out.

There are hundreds, maybe thousands of threads we don't see unless they are reported.

The posts removed in this thread were commercial, plain and simple. Those are never allowed.

 

[tahiriqbal]

With single well spaced 3W emitters, FR4 and thermal vias appear to actually be a better choice then MCPCB, as there is no insulating layer between thermal planes.

That said, I am not sure if the density we are talking about could be handled by FR4, thought it would be MUCH cheaper.

My original plan was close, but not "dense" and I simply wanted to avoid the ugly "stars" and get closer spacing. I have never done any hotplate reflowing, but it is fairly straight forward and the results (reported on diy smt sites) are better than the cheap reflow ofens sold on fleebay.

From personal experience FR4 boards are big NO NO Bean. I had few of these boards of 15 XPG and 15 XPE LEDs with ample vias filled with copper. You can see the healthy heatsink and fan ON full blast but still got me bad results (by the way LEDs were mounted by my local PCB house on FR4 board). Board and heatsink were fixed with thermal tape and screws. After running them for couple of hours at 700mA, board started to wrap and I could see few LEDs stopped working. The board was total failure and I would strongly suggest to look in to MCPB unless you want to run your LEDs at much lower (350mA) then FR4 board should be fine.