Wavelengths, A Full Spectrum Controllable LED Array

[zemuss]

I know the LDD driver is PWM but there is a circuit you can use to convert the signal with am i correct? I understand its not optimal but its been done before.

[ajmckay]

I was going to stick to 15, but 16 would be nice. You have 16 Crees on one channel? Have you driven them at 1000 to see what the total voltage drop is?

Actually I haven't measured it... Maybe I should. I suck at electronics but if I understand it correctly you just touch one lead to the beginning of the string and another lead to the end of the string...

 

I calculated the vF to be between 3v and 3.2v @ 1000mA. I'm runnng the power supply at 52v (it's adjustable).

 

Either way it seems to be working. I'm not sure what the effects are of supplying less voltage, but if needed I could easily move 1 RB to the white string or something.

 

Holly Moses !! You didnt get confused with all those black wires!

Looking back using all black wire was probably not the best idea. Especially considering I had red, green, and white wires which I could have used also. Part of it was I just wanted it to look super clean though, so I think that's what ultimately made me choose to use all black.

 

I was very meticulous hooking everything up, working 1 channel at a time. I also used little labels at the ends.

 

I know the LDD driver is PWM but there is a circuit you can use to convert the signal with am i correct? I understand its not optimal but its been done before.

I'm sure that someone who is very knowledgeable in electronics could build an analog solution, but honestly why would you?

 

Granted I would love some analog knobs just to mess around and find the right color blending, but the PWM is cool because it can do the fade on/off and you can still play with the blending, it's just a little more of a pain with buttons.

[zemuss]

I purchased the same power supply.

 

If I build the analog circuits I will put some type of video up on them.

[AlanM]

Actually I haven't measured it... Maybe I should. I suck at electronics but if I understand it correctly you just touch one lead to the beginning of the string and another lead to the end of the string...

 

I calculated the vF to be between 3v and 3.2v @ 1000mA. I'm runnng the power supply at 52v (it's adjustable).

 

Either way it seems to be working. I'm not sure what the effects are of supplying less voltage, but if needed I could easily move 1 RB to the white string or something.

 

You should be able to just use a DC voltmeter which has an internal resistance of megaOhms and touch the leads to the beginning and the end of the string while it's running. Be sure it's on DC Volts first before you do it or you might let the smoke out of something. I think you either have enough volts or you don't at that current and they would flash or something if it was too little. Not sure what the effect of supplying too little are either, but that's my guess.

 

I'm glad you posted this. Now I'm sure I'll be able to turn up my PS a bit and eke out another LED and also sure that if I can't decide between Cree or Luxeon I am not limited by forward voltage even if the specs show Cree coming in a smidge higher.

[ajmckay]

You should be able to just use a DC voltmeter which has an internal resistance of megaOhms and touch the leads to the beginning and the end of the string while it's running. Be sure it's on DC Volts first before you do it or you might let the smoke out of something. I think you either have enough volts or you don't at that current and they would flash or something if it was too little. Not sure what the effect of supplying too little are either, but that's my guess.

 

I'm glad you posted this. Now I'm sure I'll be able to turn up my PS a bit and eke out another LED and also sure that if I can't decide between Cree or Luxeon I am not limited by forward voltage even if the specs show Cree coming in a smidge higher.

I would still plan conservatively though. The drivers are not 100% efficient. Meaning that it will lose a few volts between input voltage and output. I don't know the math, but I know that if my power supply is feeding 52v to the drivers, the driver may put out a max of 48 to the LEDs. At least this is how I understand it.

[ajmckay]

Okay, so I realized that back on post #15 I talked about the splash shield and driver enclosure plans but I failed to upload the image. So I fixed the post and here it is again, just in-case.

 

[zemuss]

Bravo.. Thanks for the drawing and your paint shop skills are impressive.

[ajmckay]

Bravo.. Thanks for the drawing and your paint shop skills are impressive.

Have you seen the "Mona Lisa in MS paint" youtube video? That's totally me.

 

 

 

 

 

Not... But thanks for the compliment Paint is nice to get a quick diagram put together.

[zemuss]

Nope haven't seen that.. Need to google it.

[zemuss]

That is epic!

[AlanM]

I hope mine comes out as cleanly as yours. I've got all of the electronic bits. Now I just need the LEDs and heatsink. (and for the tank to get plumbed),

 

Edit: Is there a way to get a good picture of the thing shining on a piece of white paper say 30 inches away to see if you can see color bands (and maybe disco when over water) from your red/blue/cyan, etc being separated by the distance they're apart? It's probably very difficult to get the colors to resolve in a picture.

 

30 inches is 18 inches of tank plus 12 inches above the water, which would be about what I'd be doing.

 

Are you using optics? and what height are you hanging yours over the water? I remember you saying that your tank was 16 inches high, right?

[ajmckay]

I hope mine comes out as cleanly as yours. I've got all of the electronic bits. Now I just need the LEDs and heatsink. (and for the tank to get plumbed),

 

Edit: Is there a way to get a good picture of the thing shining on a piece of white paper say 30 inches away to see if you can see color bands (and maybe disco when over water) from your red/blue/cyan, etc being separated by the distance they're apart? It's probably very difficult to get the colors to resolve in a picture.

 

30 inches is 18 inches of tank plus 12 inches above the water, which would be about what I'd be doing.

 

Are you using optics? and what height are you hanging yours over the water? I remember you saying that your tank was 16 inches high, right?

Tonight I can try to take a picture/video of a piece of white paper at around 30 inches. Hopefully no color banding or disco, but if there is it should be easy enough to reposition some of the LEDs due to the simplicity of the t-slot heatsink.

 

The LEDs are pretty close together - no optics, and I plan to hang this between 6-8" off the water for my 16" high tank. I still have to finish re-assembling my tank as well before it gets put to use.

[AlanM]

Tonight I can try to take a picture/video of a piece of white paper at around 30 inches. Hopefully no color banding or disco, but if there is it should be easy enough to reposition some of the LEDs due to the simplicity of the t-slot heatsink.

 

The LEDs are pretty close together - no optics, and I plan to hang this between 6-8" off the water for my 16" high tank. I still have to finish re-assembling my tank as well before it gets put to use.

 

 

It seems like if they're around 1" apart, and the spread is 120 degrees FWHM (Full Width Half Max) with no lenses you'll end up with very little color banding around the edges because at 24 inches from the sandbed it seems like that's 24*tan(60) which is 41" radius to get down to half intensity. They'll likely all blend together.

 

I think it's when you start putting 40 or 20 degree optics that you start seeing sharp lines between the colors. At least that's my guess at where people have observed prominent disco lights moving around on the sand.

[ajmckay]

Stop, picture time.

 

Here's a picture of the paper on the wall (11x17 sheet) from about 30" away.

 

Here's a closeup of one of the corners that's lifted from the wall exposing some slight color banding, though not very noticeable at all from more than 6" away.

 

Spacing for the exotics. Note that they're closer when measured diagonally.

 

Spacing for the BR:NW

 

Also I've added a video in the original post!

[AlanM]

Nice video. Cool to see how it really goes together that pictures dont get across.

 

Do you think it would be too tight to wire it up if the tails of the colored solderless stars were all rotated around 180 degrees so they kind of fit between the stars and the stars could be on adjacent rows touching each other with the emitters in kind of a zigzag pattern?

 

Seems like that would be a closer packing arrangement than what you have. It would letyou move your white/RB/V rows in towards the colors one row on both sides.

[ajmckay]

Thanks, the video is sort of crappy (shaky), but I'm working on my video skills. I need a wearable microphone. Thinking about getting a gopro camera for mountain biking and underwater footage sometime.

 

Anyways, regarding the re-arrangement of the LEDs I'm not sure if it would fit that way, I would have to play with it. I think I'll put it up over the tank though before I mess with the spacing at all.

 

Even though it's not nearly as hard as prying off adhesive or re-drilling holes it still does take some time to re-position the LEDs, mostly in re-wiring and let's not forget the cost of the thermal grease (arctic silver is $$$ - I'm thinking of switching to the ceramique stuff that costs a few $ less but comes with a lot more). Since I'm using solid core wiring it can be snaked through the LEDs pretty well and it stays in place so I don't think that would be an issue. Honestly though I'm not sure how much closer I can get everything. I could maybe squeeze it down into fewer rows, but along the length of the heatsink it's pretty close.

 

I suppose that's one of the potential drawbacks of the solderless LEDs - you do have to plan a little more as far as how they'll be configured. The only reason I got them was because the regular NW LEDs were out of stock and the exotics are only available in solderless. Overall I'm happy with them because they are very convenient and produce a quick and clean build though the LEDs would be a bit tighter if I had used regular stars. Then again I can't blame it all on the solderless LEDs, I think the t-slot heatsink also makes it a little harder to get the LEDs really close because you have to deal with screws and a pre-determined spacing along the width of the heatsink.

 

Honestly though I don't anticipate any banding issues with this build. If they are noticeable though It won't be a huge effort to re-arrange things.

[AlanM]

Back to the top with you!

 

After seeing your build and the mccorry build on a MakersLED heatsink I finally pulled the trigger on my parts with LEDGroupBuy. Milad can split some of the credit with you two for the sale. I'll post a build thread at some point when I've got my soldering iron warm.

[MeepNand]

Looks good man. I thought PWM was essentially a replacement for a potentiometer/resistor, but I'm probably wrong.

[ajmckay]

Back to the top with you!

 

After seeing your build and the mccorry build on a MakersLED heatsink I finally pulled the trigger on my parts with LEDGroupBuy. Milad can split some of the credit with you two for the sale. I'll post a build thread at some point when I've got my soldering iron warm.

Looking forward to it! Man I love LEDs... Some nice, clean builds going on.

 

Looks good man. I thought PWM was essentially a replacement for a potentiometer/resistor, but I'm probably wrong.

PWM is basically turning the LED on and off really really fast. By varying the duty cycle (the amount of time the LED is on vs. off) you can make it appear dimmer or brighter. It's pretty awesome though I do like the thought of having a manual knob for testing the color mix. This is a little harder to do with a digital controller.

[FishBrawler]

So I notice you don't have any optics. Is there any plans for optics?

[ajmckay]

Nope, no plans for optics. The tank is only 16" deep and the light will be mounted no more than 6" off the water.

[ajmckay]

Okay so I don't have my tank up yet, however I do have a FW up now.. So I was anxious to hang it so I make a quick and dirty bracket and put it over the FW! Definitely too blue for FW fish, but it does make the tetras and blue ram cichlid I have look awesome!

 

Enjoy. Tomorrow I'll mess with the spectrum. This is 25% hung about 15-16" off the water (my bracket setup wouldn't let my drop it down much).

 

 

 

[VABumpkin]

Very nice work! The blending is impeccable. However, the end result is a bit too blue for my taste, I would have done a few more whites IMO. But really, nice work.

[ajmckay]

Soooo.... Update time? I can't believe it's been so long since I built this. I used it on my FW tank for a while until one day the power supply decided to fry.

 

 

Anyways, I'm setting my 40 gallon reef tank back up in the next week or so! So I need to order another power supple stat (hopefully a better one!).

[zemuss]

I never followed through on my build but want to get it up and running soon. However I am going to supplement it with t5's for light spread I think.