DIY Moonlights

A revival just as I was about to post. Excellent.

I just started a new set of "moonlights" for my 15H, which is finally set up and cycling. However, I am taking a slightly different approach and am incorporating some different color LEDs in the hopes of producing a more colorful "night". In addition to blue, I will be using green and UV...
newmoonlights.jpg


I have to run to class, will be back around 5PM with more details.


Marty
 
So, the basis upon using multiple colors, multiple wavelengths, of light came from some research on photosynthetic corals. Obviously it's well known that they react to certain spectrums more than others, and I was able to narrow down some of the exact spectrums using a few sources, http://www.reefs.org/library/talklog/s_tyree_060202.html especially. Section II covers what I was interested in.

*Remember, this is just an experiment, I have no data to support any hypothesis.*

The wavelengths specifically mentioned and the LED that most closely matches are as follows:
310 to 380 nm None available
380 to 470 nm UV LEDs at 390-395nm and 400-410nm
430 to 490 nm Blue LEDs at 460-470nm
440 to 500 nm Blue LEDs at 460-470nm
500 to 540 nm Green LEDs at 515-530nm

I chose only a single wavelength UV LED, at approximately 395-400nm, and will be using those with the blue and green LEDs.

As far as the design of the array is concerned, it is fairly simple, involving only 8 strings of 2 LEDs each. Each color will be wired to an individual switch, so I can control which are on. Hopefully I will be able to test each color individually and in combination with other colors, over one week periods.


Regards,
Marty
 
OK Siapin - sorry for the delay. I got moved to a different location at work and can't play on the fish boards all day anymore. =)

If we assume that you'll use a 12v power supply, we can drive those LED's at 25 mA by using the following resistors:

1/4w, 100ohm resisitor for a three bulb series.
1/2 w, 240ohn resisitor for a two bulb series.

It's up to you as to how many bulbs you use, and how you mount them. I went with four bulbs, two (2) bulb series, in a pvc bar, and here is what I used for wiring:

105579LED_Drawing2.jpg


HTH, can't wait to see your results.
jp
 
I think I want to try and go with 6 bulbs to begin with, but nothings set in stone.

You said something about using a 12v powersupply...where do I get something like that? Is there a link that I can see better of what you're talking about? I was thinking about using a 9v battery possibly. How long would that last? Is that better/worse of a choice? I probably wouldn't put that on a timer, right? I'd prefer a timer, so that counts out a 9v battery. I possibly want to add more LED's in the future. Would the 12v, like you stated, work fine with more LED's? My resistors are 510 ohms, and these are the only ones I have, so I really don't have much else to work with.
 
Anybody remember this thread? Well, I finally got to wanting to finish this thing. I need to buy a power supply, probably this one: item #220096179904. With 4 LED's, I went to the calculator page talked about at the beginning of this thread (led.linear1.org/led.wiz).

With my specs, I entered this:
12 - Source voltage
3.4 - diode forward voltage
20 - diode forward current (mA)
4 - number of LEDs in your array

Solution 1: 2 x 2 array uses 4 LEDs exactly

+12V R = 270 ohms
R = 270 ohms

___+LED-__+LED-____270 ohms resistor___then what?
/
+12V
\____+LED-__+LED-____270 ohms resistor___then what?



The wizard says: In solution 1:
-each 270 ohm resistor dissipates 108 mW
-the wizard says the color code for 270 is red violet brown
-the wizard thinks 1/4W resistors are fine for your application
-together, all resistors dissipate 216 mW
-together, the diodes dissipate 272 mW
-total power dissipated by the array is 488 mW
-the array draws current of 40 mA from the source.


Do I connect the two resistors together? Any other input before I get this all started? I was wondering about my resistors...I was planning on buying 1/4W resistors at Radio Shack...should I get 270 ohm resistors rated at 1/4W??

Thanks for the help.
 
Hello Siapin - oddly enough I had to revisit this myself, to build some moonlights for a nano I'm putting together.

What you are missing is that the resistors connect back to one of the power leads - check out my diagram. You are making two loops through the sets of LED's and the resistor.

105579LED_Drawing2.jpg


Mock it up using alligator clips before you start soldering, and good luck!

jp
 
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