View Full Version : Nick's Project : Underwater Spotlights & Lighting...

15th October 2010, 01:14 AM
So, the other night, i'm out fishing off a pontoon (approx 2m water @ high tide)

I had a couple of loaves of bread to get the fish in the eating mood.

Got bored, had a couple of those tiny glow sticks (3mm x 50mm long) which i'd previously rigged to line for night fishing. Tossed them into the water just out from the pontoon and the amount of light they put out was enough to see the baitfish in the water... When I left, I retreived them and pondered getting some uber big glowsticks, to go back and do the same but with much more lighting next time to see

a) what was in the water below
b) see how nuts and how many I could source
c) why the hell not, for shits & giggles value.

After doing some research, I discovered that the fishing industry (commercial) goes through MORE glowsticks than all the pill popping ravefags combined.

The glowsticks are relatively cheap, but I was starting to dislike the whole "use once and discard' idea...

A week or so later, and I have gotten to thinking, that its been a while since i've got in touch with my inner "mad scientist", so I did some googling for underwater LED's and stuff. I concluded that I could come up with something waterproof and home made, that I could recharge and have some fun with. And here is where I start sharing my adventure with you all.


What REALLY got my brain ticking, was this video. Obviously a more professional / expensive idea, and since I don't own a 72' cruiser (haha) This video make me think a bit more about the viability of such a project.


I've got 4 x brand new 11.1 Volt (1800mah) Lithium Polymer batteries from RC helicopters laying around Cost me like $120.
Just ordered a pack of 50 x 140,000 mcd white LEDs off ebay from China for $14 delivered. (if my maths are correct, thats 7 million candle power worth)
I'm going to need some resistors, wire, a pair of sealable waterproof ABS cases

After doing the maths, I will wire two pairs of liPo batteries to make two seperate "underwater torches" in series.

So each one should have 22.2 volts @ 1800mah. Neat!

Plugged the specs for the Led's into an online calculator (I hate maths) and came up with the best way to wire up the two seperate "banks" of underwater spotties...

Pretty stoked, 60mA current, from a 22.2v @ 1800maH power source should be good for quite a while underwater.

Also, this will give me 2 x spotties @ approx 2.5 million candle power... not too shabby!

So in about two weeks, once the LED's are in my hot little hands, I will grab my 6 x 33 ohm resistors & switch from Jaycar, grab the soldering iron and go nutso... I will post pics, build updates etc in this thread, for those of you who are diehard tech heads...

And then i'll get down to the water, burley it up, chuck the spotties on and put the video up on youtube...

Hell, it might even help me catch some fish...


15th October 2010, 07:30 AM
Hahaha, good work nick.

Atleast when the LiPos shit it and try to grenade themselves they'll be underwater.

15th October 2010, 09:32 AM
awesome idea, and yeah all those glow sticks can't be good for the fishys

18th October 2010, 09:06 PM
Make me one to put on my spear gun :)

18th October 2010, 10:04 PM
So i'm going through the garage tonight, and WTF do I find?

Something from a project I started (and failed at) possibly 8 years ago.

I just discovered I already have 400 x Ultra Violet (almost black light) LEDs :)

Resistor Identification (yes, I haven't memorised anything, ever!)

And a dickload of 1 Ohm resistors (that apparently match - or did back when I purchased the LEDs off ebay)

Luckily everything was labelled, so plugging in the specs into the online calculator was easier

The calculator doesn't like me using any combo @11.1v with the 1ohm resistors, doh.

So now my prototype will be running

1 x 7.4v @ 1000 maH LiPo Battery (from an RC chopper)
3 x 3 array of UV Leds (rated at 3000 mcd) the ones I have on order are 140,000mcd ;)

Because of my stupid decision of resistors 8 yeara ago, there is a HUGE current drain @ 1ohm - much more than I will have with the second generation spotty.

each 1 ohm resistor dissipates 160 mW
the wizard says the color code for 1 is brown black gold
the wizard thinks 1/2W resistors are needed for your application
together, all resistors dissipate 480 mW
together, the diodes dissipate 8640 mW
total power dissipated by the array is 9120 mW
the array draws current of 1200 mA from the source.

So if my maths are correct, this prototype build will be pretty bright, but will only burn for less than an hour a charge... oh well, something to play with until my LEDs and Resistors arrive ;)

Pics to come when i've finished soldering :)

And yes, these will be for sale (waterproof) if I can develop the correct ABS housing for them...

18th October 2010, 10:25 PM
That's all very well and good Nick, but..
wtf were you doing with 400 black light LED's?

18th October 2010, 10:40 PM
A bit ashamed to admit, but I won an AE71 on ebay for $51 and I planned to pimp it out with black lights for cruising :P

But lost inspiration when I discovered how much hard work it was to solder one array :P

18th October 2010, 11:37 PM
OK, I think I remember why I never followed through with the 400 x Black Light LED project :P

Basically 3000mcd = pissweak. My pee glows brighter than 9000mcd :P Glad I went for the 140,000 mcd LEDs right now...

Pics of prototype (and proto fail, haha)

3 Leds in series with 1 Ohm resistor

3 x LED's lit up


Beamed at a sheet of white paper, 30cm away...

Not exactly daylight, but, a fun exercise to get me in the mood for when the AWESOME LED's (tm) arrive :D

By my calculations, the finished product will be ~282 times brighter than this :P

19th October 2010, 12:25 AM
Just got my ebay notice that my 50 x 140,000 mcd LED's have been shipped from china.


Then I discovered some 1 watt LEDs at decent prices 1watt (340,000 mcd!)

I guess we'll see how my underwater torch works first