LED Fixture Build --Kcress--

[kcress]

I recently had the 90W MH bulb burn out on my existing tank whose inhabitants are waiting, (probably with some annoyance at the pace), for their new digs to come on-line.

See: Join me for a strange one...


After discovering the cost of a new MH bulb was about $40 I decided to plow the money into a LED fixture.


I've always had an idea about how I'd build one and decided to try it as an experiment. Who knows if it will work or not? One way to find out.

I like a much whiter - less blue look - than seems to be popular. I'm also considering the design for lighting a FATS (Flooded Algal Turf Scrubber). And, even as a living room indirect ceiling flood since we need one. So, I got a pretty "white" mix.

All Cree XPs.
(6) Warm White
(6) Royal Blue
(12) Cool White

I also bought a Meanwell CEN60-48 before it was brought to my attention that this drive has a nasty ripple voltage. So, we will be discovering if that (really) presents a problem or not. Others have also picked up some MWs with the same nasty ripple specs.

My plan is to use a thin sheet of aluminum about 1/16" thick. I'll route out a particular shape for the LEDs and then bend the metal so it looks like flower petals around each LED. This will do two things. It will provide some modicum of reflector to limit the sideways cast light from these LEDs. More importantly, the petals will allow excellent radiant cooling and provide for convection cooling.

I'll be driving these LEDs around 800mA.

So lets begin!

First up. Cadding the needed sheetmetal work. I use AutoCad then pass the resulting DXF file to a CAM program for generating the needed tool moves.

Here's the drawing. If you look closely you will see the two hole drill points for mounting each LED. The predominant shapes are the petals that will be bent downward. All the other shapes and holes are for mounting the fixture within a housing and for hanging the fixture and mounting ancillary hardware.

BTW There's no reason I couldn't use optics too. Presently I'm not. If this fixture ends up over my new build I'd need them.

The sheetmetal will be 9" x 19".

 

[ghellin]

Following along!

 

[jfarabaugh]

2 things IMHO

The flower petal idea will make the color blending even worse.

I really dont think you are going to like the look of that LED combo. I like the whiter looking light as well but I thing you need to add more blue to the mix.

I got a nice white look by running a 1:1 mix.

http://www.reefcentral.com/forums/showthread.php?t=1950067

 

[widmer]

Can't wait to see a picture of this thing when it's made. Hopefully you can paint the aluminum red and have a green power cord :lol:

In all seriousness, looks like your design is going to allow for tremendous convective cooling.

jfarabaugh - the LEDs are placed between 2 & 3 inches apart... the flaps are going to be nowhere near long enough to confine the light coming out of the emitters to angles that won't blend well...

 

[edsreef]

I also don't think you're going to like that color combo. And if you plan on having any corals, esp SPS, they won't color up very well.

 

[TenKreefer]

Kcress is building this....I will follow blindly with faith

 

[kcress]

Kcress is building this....I will follow blindly with faith

jfarabaugh and edsreef:
As for color.. Yes we will see. But remember as I was buying these LEDs I was thinking FATS or a soon to be torn down FOWLR.

Also, I have, for 14 years, had strictly off-the-shelf high CRI white, white, white MHs. That is what I see when I snorkel around Hawaii for a week. Not some strange blue glow.

But in fairness I have never had a reef tank so I may need to change it up.

As for my big build I have to consider the fact that during daylight hours my tank will be lit with direct (white)sunlight. It may be weird having it all turn blue later in the day as the LEDs crank up. But you bring up a point. I will need to think about it. We should take that up in the other thread, as soon as I start on the lighting.

 

[edsreef]

There was some recent discussion about sunlit SPS tanks in the SPS forum:
http://www.reefcentral.com/forums/showthread.php?t=1964805
Compare colors to "typical" lighting SPS tanks & it should help. They will grow well but the colors aren't there.

 

[MarcBergmueller]

I too like the "as snorkeled look" I have a 50/50 mix of CW/RB and its too blue.
May I suggest CNCing your "flowers" different. How about cutting all the way around your Flower except for one "petal" which you could bend to angle your light. I guess that would only matter if you are using optics.
I've done some band lighting and think it is quite similar. You light your subject from slightly infront and above, not directly above. That leads to wash out. MH radiates around and bounces off the reflector at many angles. My opinion as to why people feel LEDs wash out a tank. I'm working on it.
I'll be following along.

 

[Cuervo]

I too like the "as snorkeled look" I have a 50/50 mix of CW/RB and its too blue.
May I suggest CNCing your "flowers" different. How about cutting all the way around your Flower except for one "petal" which you could bend to angle your light. I guess that would only matter if you are using optics.
I've done some band lighting and think it is quite similar. You light your subject from slightly infront and above, not directly above. That leads to wash out. MH radiates around and bounces off the reflector at many angles. My opinion as to why people feel LEDs wash out a tank. I'm working on it.
I'll be following along.

This makes alot of sense... A person under more natural lighting is hit from many angles, whereas a spotlight causes people to get washed out - one of the reasons they use so much makeup for TV.

Quite the quandrum though, as diffusing the light might make it seem more natural, it's counterproductive to getting as much light as possible on the corals.

 

[CJO]

There's a DIY LED thread around here somewhere that might help

LOL

CJ

 

[kcress]

There was some recent discussion about sunlit SPS tanks in the SPS forum:
http://www.reefcentral.com/forums/showthread.php?t=1964805
Compare colors to "typical" lighting SPS tanks & it should help. They will grow well but the colors aren't there.

That was most interesting! Thanks.

I too like the "as snorkeled look" I have a 50/50 mix of CW/RB and its too blue.
May I suggest CNCing your "flowers" different. How about cutting all the way around your Flower except for one "petal" which you could bend to angle your light. I guess that would only matter if you are using optics.
I've done some band lighting and think it is quite similar. You light your subject from slightly infront and above, not directly above. That leads to wash out. MH radiates around and bounces off the reflector at many angles. My opinion as to why people feel LEDs wash out a tank. I'm working on it.
I'll be following along.

An interesting suggestion. I could do all the petals and add a spot that allows a LED to be angled slightly. I'll need to see how what I've got will perform thermally since doing a full cut out reduces some of the area for cooling.

Thanks for the wash-out info.

This makes alot of sense... A person under more natural lighting is hit from many angles, whereas a spotlight causes people to get washed out - one of the reasons they use so much makeup for TV.

Quite the quandrum though, as diffusing the light might make it seem more natural, it's counterproductive to getting as much light as possible on the corals.

My concern with front lighting is that it sort of 2Ds the tank. If light comes straight down you can have depth because of shadows. With frontal lighting you lose all depth from shadows. When lighting people you want to see their faces and are not interested in the 'depth' of the stuff around them.

If I light my big tank from the front with room light all that structure flattens right out. Compared to top lighting.

This is an exaggeration but shows what I mean:

There's a DIY LED thread around here somewhere that might help

LOL

CJ

:spin2:

 

[kcress]

Here I've fed the CAD drawing(Computer Aided Design) to my CAM program(Computer Aided Machining)

This is where I select what tool is used and how it's used to cut the aluminum.

The result is more than one thousand eight hundred motion commands.

These commands will next, be fed to a CNC router that will do the cutting.
.
.
.

 

[Cuervo]

agreed on the lighting.. teasing us with the CNC stuff

that is sweet though man, wish I had easy access to a CNC.

 

[MarcBergmueller]

What CNC machine do you have? I completed my conversion of my X2 mill this fall and am slowly learning.

 

[MarcBergmueller]

as for front lighting, think 2pm sun behind you, you still have shadows for depth. Hey, all the worlds a stage.

 

[kcress]

My CNC is a 2 x 4 foot K2 running servos.


So I've run the job.
Routers don't generally have liquid coolant systems so now I have to clean the wax off that I smeared all over to protect the Titanium Nitride router bit. It's a pain...

Here it is all cleaned up and ready to throw some bends into.

 

[friendlyAlien]

Nice! Can't wait to see and hear how it works!

 

[widmer]

That's going to look really cool when its done...

 

[CJO]

Nice... how do you plan on bending them?

CJ