Building my own moonlight (for freshwater)

[senemedar]

I always try to keep my light not much longer than 8-10 hours, but I always hated the idea of sitting after 10pm in front of the tank and don't see a thing, so the idea of moonlight was born.

Blue lightbulbs were a bit too expensive for me, so after finding some LEDs on the eBay I went for a cheaper option

I got some PVC trunking cover that I use a lot in my work, so I drilled a few holes in it and fit the diodes in.

It comes with to parts-- narrow black one and wide grey, because of the hood I have. It will all explain itself later

For a starter I wanted to see whether it works at all, so decided to solder everything together and connect to three AA batteries:

All the anodes (longer legs) were connected to each other and one wire to connect the lot to a battery, and the similars goes for the cathodes (shorter legs). I didn't need anything more at this stage, because the voltage from three AA batteries is just enough to make the LEDs shine and we don't need to be worried about too much current just yet.
I put it into the tank for a moment, to see how it's gonna look

That's it for today, as it's starting to getting a bit late... It took me a bit longer than I thought

 

[HAVAMAL]

Nice job!!!!! !!!!!!!

 

[senemedar]

Nice job!!!!! !!!!!!!

Thanks

I finally decided to go for mains powered LEDs instead of batteries, so I went to buy some resistors.
I read here that the LEDs shine brightest at 20mA, so having a 6V power supply from my wife's sewing machine I bought 300 Ohms resistors an soldered them to each diode. I choose the longer leg to fit them to, but it doesn't really matter where you put them.

I also made a little "power distribution" stripes, so I can add some more LEDs in the future more easily, if I'd need to.
Another test, this time connected to power supply:

...and it's working perfectly.

Last thing to do was to get a few screws to put all of that together with my hood:

...and finally I can enjoy the fruits of my hard-work:

Cost-wise:
LEDs - pack of 50 from e-Bay: £1.60
Resistors - electronics components store: £3.60. I could have them for about £2 (e-Bay!) but was growing impatient
Power supply came earlier with my wife's sewing machine, and is still usable if needed - I remade a spare plug that came with it so it can be disconnected at any time.
Bit of a time and sweat...

I hope you enjoyed reading about it as much as I enjoyed making it

 

[Bige]

looks cool with the ship. Looks like a movie with the search lights on under water.

 

[HAVAMAL]

Turned out amazing!!!!!

 

[senemedar]

Thanks
My only regret is, that it could be a wee-bit lighter, I recommend at least 8 diodes per row if you try something like that for yourself. I think I might add some in the future, but rather not too soon

 

[mrbee2828]

Would you mind pointing us to a similar LED post on ebay? I'd like to get mine going and I'm still really not sure what I'm looking for.

 

[senemedar]

Would you mind pointing us to a similar LED post on ebay? I'd like to get mine going and I'm still really not sure what I'm looking for.

The one I bought are those:
eBay - The UK's Online Marketplace

I've been sold 10000 mCd instead of 15000 as advertised, maybe that's why it a bit less bright than what I thought it will be, but still does the job.
What I paid attention to is the wavelength (465nm-470nm) as I read somewhere that it's a moonlight wavelength and I wanted that
Also you could do with a bit more of a viewing angle (15 - 30 degrees made the "spotlight search" effect) if you want, I personally am very please with the effect I have.
So now you now what to look for-- good luck

 

[mrhelton]

This is really cool. I'm working on my own LED strip, but don't know a lot about voltage and resistors, but I'm working on it.

Nice shoes too, I want a pair like them!

 

[senemedar]

This is really cool. I'm working on my own LED strip, but don't know a lot about voltage and resistors, but I'm working on it.

Nice shoes too, I want a pair like them!

For pair of ones like that you need to go to Poland ))
As for the diodes it's really easy and explained in details on the website I put earlier.
But in nutshell, having a 6V power supply and wanting a 20mA current on the diodes (as in my case) we need to divide 6 by 0.02 (20mA) what gives us 300 ohms for resistors. But I really encourage to do a bit more research

 

[0shayne0]

Really like this idea, maybe you can help me out as im clueless with resistors thanks

 

[senemedar]

There's really nothing complicated with that.
All you need to know is here:
LED center » Why do I need a resistor with an LED?

and here:
LED calculator for single LEDs

I recommend to browse through the site as well, as there is a few really good articles. But if you still have some questions you can PM me and I'll try to help you, no problem.