DIY Moonlights.

The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.

SparKy697

Aquarium Advice Addict
Joined
Nov 23, 2006
Messages
1,495
Location
Northwest Indiana
If you would like to have moonlights in your tank, but did not buy the fixture that has them built in. Here is an alternative to using the add on type led fixtures.

Go to EBAY and look for Blue, wide angle (+/- 100 degree viewing angle).
I found these and bought them. The exchange rate worked out to be about $18.00 with shipping. I know you can buy the pre made puck type fixtures but those have one or two LEDs and this is for 100 LEDs. I have enough to light every tank that I will ever have.

These are sold for use on an automotive application so they come with an appropriate resister to drop voltage to around 5 volts dc which is what you want for LEDs to operate. You can find 12 volt dc power packs on ebay too, as well as radio shack.

Here are the details:


I started with my All-Glass light fixture from my 29 gallon tank. It has plenty of room between the lamp and the sided of the fixture. You will have to determine if your fixture has enough room to squeeze some led's in along with the normal lamp.

img_778653_0_d1e9044649e9d9da9cb06212edb0a3dd.jpg



I removed the reflector to expose the inner workings of the fixture. Layed out where I wanted the led's to be and drilled holes that the led's would fit through.
img_778653_1_ba8f2a802802f32738975056466cb178.jpg


Inserted the LEDs to test for fit and then glued them in place. I chose to use an extra thick super glue (Cyano-Acrylate) because of it's fast drying time

img_778653_2_a0ec5387fd7fd251b1577f0e5904fc6b.jpg

img_778653_3_19bd553e1ea883e1b7bad58179ccd288.jpg

img_778653_4_96e521f56ea3cb948faa98f54f1433fd.jpg



I layed the LED's leads over so that they were parallel to the reflector. Then the wire that would connect the led's to the power supply were stripped every place it would come in contact with the led's leads. Since I had a 12 Volt dc Power supply I just used the resistors that came with the LEDs. I chose to use one resister per LED instead of using one main led. These resisters were soldered between the wire and the lead the wire was to be attached to.

img_778653_5_81c49ea7ee3de57b458373a2aad6edc5.jpg

img_778653_6_46b9baca3754e8bd75da1aef9eb2ac28.jpg

img_778653_7_89a850f773f112b678b41d19127cad41.jpg

img_778653_8_c12b77dffc600a16813819484caf8abf.jpg

img_778653_9_d8ce136cbae52c4556f6680687471ed0.jpg


Heat shrink tubing was used to provide a little mechanical support as well as insulate the leads that were soldered to the wire.

All of the LEDs soldered and glued in place.
img_778653_10_cbd7a1140634cc892b6cebf062c9dc14.jpg


The test before putting it all together.
img_778653_11_0627ff494d89c2854869da32e37bbea1.jpg


Drilled a hole for the power cord from the power pack to go through and just tied a knot in it fro strain relief.
img_778653_12_f1f4fb54abb73e34cc9455cbb92678e6.jpg



FINISHED!

The final test to make sure every thing works.
img_778653_13_39cfde19e39e64484903830a1fb456c6.jpg


I will post photos of the tank lit up with the new LEDs tonight.

The only thing left is to make the LEDs come on automatically. That will be another post.
 
Nice job...very profesional, but judging by your workbench, you have done this before..
 
I'm thinking of doing this to my new DIY canopy. I have over 100+ blue leds and UV leds. I was just going to hook 3 of them up to a 12v adapter so that they all would get 4v each. I don't use resistor nor have I ever used them before since I'm not sure exactly what they do or how to pick the proper ones. Using resistors will I be able to hook up more then 3 leds on a 12v adapter? For example 5 or 10?

As for other hobbies. I mod computer! :D Anyone else here also a moder? Show me your cases!
 
Using resistors will I be able to hook up more then 3 leds on a 12v adapter?

Yes. If you hook the LEDs up in parallel and use a resistor to limit current. You can use as many LEDs as your power supply can handle.

LEDs by nature will drop roughly 3.6 v across their leads. With a 12 v power supply that leaves 8.4 volts that you have to figure out what to do with. This is where the resistor comes in. By adding the resistor in series with the LED, you can give the unwanted voltage a place to go and be used as heat. It also gives you a way to limit the amount of current the LED gets passed through it. In this drawing you see a 500 ohm resistor in series with the LED. Since we know the voltage across the resistor and the value of the resistor itself we can use ohm's law to calculate the current through it. 8.4v/500 ohm=.0168A (16.8mA) This is well below the max rating of the LED of 30 mA.

In our circuit below you can see that the power supply is rated at 1000mA this means the we can use 1000mA/16.8mA=59 LEDs wired up the same way and the power supply will handle it.

And yes, the amount of current passing through the LED is what controls it's brightness. You can even exceed the rated max if you like by using a smaller resistor, the device will just not last as long.

Keep in mind that these values only exist in the perfect world. Each resistor will not likely be 500 ohm and even the LEDs will not all drop 3.6v either. Some experimenting is always required.
 

Attachments

  • led_circuit_683.jpg
    led_circuit_683.jpg
    52.8 KB · Views: 64
Since we know the voltage across the resistor and the value of the resistor itself we can use ohm's law to calculate the current through it. 8.4v/500 ohm=.0168A (16.8mA) This is well below the max rating of the LED of 30 mA.

Oh, right. Ohm's law. Of course.

What the h**l are you talking about, Sparky? What's a resistor? LED? I barely know what the letters stand for. I hate you and redswi because you're evil and know how to do things that should be beyond the scope of human ability.

It needed to be said.

Oh, right-the lights are cool. Whatever.
 
Thanks for the refresher....I havn't thought about ohms law in a long time...I need to make a support rail for a glass cover on the corian tank, and after this post I think I'll add some leds to the rail...


BTW are you as hurt as I am???
I hate you and redswi because you're evil and know how to do things that should be beyond the scope of human ability
 
I'm curious, why 100 degree viewing angle? Is that because you wanted it to hit the reflector? The reason I ask is because I want to add additional moonlighting to my Current USA Sattelite fixture and I was going to do it replacing the existing two with 18000 mcd superbright bulbs and 100 Ohm resistors, but they only come in 30 degrees, I thought that would be enough to aim down at the tank.
 
I'm curious, why 100 degree viewing angle?

I chose the 100 degree LEDs because I did not want to see beams of light in the tank. I found that by placing these about 5 inches apart in an 18 inch tank gave me good coverage overlap and you can not tell where the light originates from. You can certainly use the 30's, I believe you will see more of a column of light in the water. If you like that look you are in business.

HTH
 
Back
Top Bottom