Wiring LED's into a waterproof tube

[Stusi]

First of all i wasn't sure where to put this post so if it needs to be moved or reposted elsewhere please let me know and i will do so.

 

So heres a quick background, i'm a senior in highschool and at my school it's tradition to ask the girl you want to go to prom with in a very creative way. I had some friends write "Will you go to prom with me?" in huge letters in the girls street, others had streakers at a football game with "Ally prom with me?" written on their butts, and other creative ways, some romantic, some not so much (is male frontal nudity a good way to ask a girl?). Anyways here is my idea...

 

I want to go to the creek like we always do and have a small waterfall light up suddenly from behind (this is at twilight so it will be kind of dark) and the lights will spell out "Prom?". The waterfall is small... only 6 feet wide by about 3 feet high. So i decided i would wire together a long line of LED's and put them into waterproof tubing of some sort and secure the tubing to some plywood whichi can then put behind the water so the light will be coming through. My problem is i have never worked with LED's, or electronics, in my life. I am a huge computer nerd and can fix just about anything and i love a good project so i decided this would be great. Anyhow i was just wondering what the best way to go about this would be. I thought of just using Christmas lights to spell it but i really like the look of the LED's as this girl is really into astronomy and stars so it will look more like a constellation. I think i could find some Christmas lights that use LED's though couldn't I? Anyways, if i did make my own setup... what kind of power would i need (a car battery perhaps?) and what would be the best way to wire the LED's so they can all turn on at once and be getting splashed on? Any help would be greatly appreciated as i will start buying materials in a few days. Also if i am successful i will have to include some pictures and let you all know if she said yes.

 

Thanks in advance!

[5614]

Nearly all small christmas lights are LEDs... if you can't find any in shops then you will have to wire together a bunch, which isn't very hard but may be time consuming, esp. if you want to wire them all in parallel. You have to be careful with the christmas lights idea because some xmas lights need to be plugged into the mains, which is not practical.

 

As for a power source, well it really depends on what LEDs you use and how many. I would suggest just building the circuit and leaving the power until last. Once it is built just use trial and error. Stick in a 9V battery and see how long it lasts. If you have loads of LEDs then it will probably drain the battery quite quickly, so maybe try two 9V batteries in parallel to each other.

 

The 9V battery works well for 5mm diameter LEDs, I don't know what size LEDs you have in mind. You can them the size of normal light bulbs which run off the mains (240V in the UK), but this is not very practical.

 

A note on the water proof idea... I don't know what facilities you can use to make this and I don't know how this will attach to your waterfall but if water is flowing over the top of it and down the sides then the bottom doesn't have to be total water proof. Of course if the bottom is sitting in the river or water can splash up this is a different matter, but the bottom doesn't necessarily have to be sealed.

[Klaynos]

I would probably go down the route of teh xmas lights for the outside, made out of LED's, for the power supply for them you'd have to look at the transphormer that comes with them...

 

You could build your own, and the powersupply would depend alot on the number of LED's you used, and putting them into series would be a sensible idea iirc... And some seethrough hosepipe, would probably be a bit fiddly though...

[5614]

Put the LEDs in series?

 

Then you would need a massive voltage and if one broke they would all fail.

 

You want to do it in parallel so that the voltage is the same across all the LEDs and if one fails it will not effect any of the others. The only downside is that this requires more wiring. All xmas lights are wired in parallel.

 

Good point on the xmas lights though. If they plug into the mains but have a transformer it will say on the transformer "Output: __V" so say it says 9V then you could use 9V batteries for power. Note that having a lot of LEDs in parallel will require a high current supply, so attaching a few batteries in parallel will help.

[Klaynos]

You see, I was thinking parallel, but wrote series... I should be asleep...

 

My appologies...

[Stusi]

Thank you all for your help... i wonder if i can even find christmas lights this time of year in stores. I guess i will look for a website. I don't really know what size i want... it would be fine by me if they were dim as not much light will be needed at all. Also to whomever mentioned the tube being open at the bottom.. i too thought of this but it's still gonna be quite hard to pull it all through... oh well. This helps me immensley... thank you guys for all the help. Also if you have any more genious ideas or find waterproof x-mas lights with a transphormer on the net lemme know.

[5614]

Just to a search for 'christmas lights' on ebay! And maybe include the word 'outdoor' in the search.

 

e.g. http://cgi.ebay.com/CHRISTMAS-LIGHTS-WHITE-WIRE-GOLD-LIGHTS-MINI-BULB_W0QQitemZ6618531173QQcategoryZ7269QQrdZ1QQcmdZViewItem#ebayphotohosting

or

http://cgi.ebay.com/100-Blue-Indoor-Outdoor-string-christmas-lights_W0QQitemZ4453382090QQcategoryZ116022QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

or

http://cgi.ebay.com/2-PURPLE-ROPE-LIGHTS-36-IN-OUTDOOR-WEDDING-CHRISTMAS_W0QQitemZ4453524847QQcategoryZ38229QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

NB: these are 110V which are probably not suitable. Remember to check the voltage and if there is a transformer etc.

 

As for the waterproof part, well that's down to you. The actual plastic top of the LED will be waterproof, it is the electronics and wires that can't get wet (if they are not insulated, if everything is insulated and water proof then you do not need special waterproof packaging). If your packaging is water proof then it will protect the electronics inside. You just need to make holes in the packaging so that just the top plastic part of the LED can pop through and make sure that it is so tight that no water will get through.

[Klaynos]

If you use outdoor light and only want to use them for a short time you can probably get away with leaving it all and putting the powersupply in a plastic bag to keep it dry...