Ok guys... Im new here and Ive seen great help threads but nothing on this... My idea is awesome (imo) and I really want to do it. Ok so here we go. My idea is, I have this old lego table, and its the perfect size as a coffee table so I stripped off the lego peices stuck to the wood and I put plexiglass down over that and it looks cool. Its all wood, except the plexiglass of course, so its easy to drill into and its light. The real thing I want to do is put some LEDs on the side of this thing to light of the plexiglass... Im debating whether to make them plug into my wall or have them run off batteries... I really dont care which one, but I just CANNOT figure out the calculations... I plan on putting 10 3mm LEDs in this to make it light up, but how much of a resistor do I need or how many and how the hell do I wire them?! lol. Im really confused. I have messed with leds before... mainly with my xbox... but everytime I do something I guess I use the wrong resistor because it gets SO HOT it melts the solder joining the resistor to the LEDs. I would REALLY appreciate some help with this because itll look great in my already glowing room... (blacklights and bright ass computer) Thanks alot guys!!!

http://www.electrician.com/resist_calc/resist_calc.htm

Find out the current of your wall socket (a multi-meter or your local electrician can do that for you, or you could always just stick a fork in the socket ), and then use that calculator to help you with resistors and stuff.

Its more calculating... Im just not good with that... lol. Can anyone just tell me?

Well, I'm not good with power here (Oooh... shiny capacitor...), so htat's about the most I can say for now.

There are some members here who know much more about this stuff then I do, so just sit tight and patiently... *grabs some chains and ties you up* There.

lol Thanks for the help though man. Im trying to figure out these resistors I have with that calculator...

what color LED's are you going to use, cuz diffrent LED's use diffrent amounts of voltage

some additional info such as the voltage rating and current requirements of the LEDs might be of use

I think Ive got it figured out. Thanks for the help! Ill be sure to post some pics when its all done!

If you're using regular leds that every modding store sells, they are 5mm 3 point something volts when i want to put a ton of them, forget calculating just add a 470 ohm resistor to each and plug it all to the 12V line on an old PC power supply the psu will supply more than enough juice and you'll have each led as bright as possible which can be a bit off(sometimes more or less than a bit) if you mess up your calculation.
I never had any problems that way, and i once lit a whole case with leds.
You have an idea of your idea here with the mouse pad and the plexiglass under the drives leds are the best thing for comps, not power hungry and lights up a ton (or a storm, whatever )

That pic is hot. I am done with all the work on the table! I have now reached another problem though... I forgot that it takes a motherboard to turn on a powersupply... does it not? Well thats what I was going to use to power my 10 LEDs... I had a spare 250W power supply sittin around so I thought I would put it to use and hook it up... but Im retarded and forgot that it needs the mobo. Anything I can do now to get this thing to work???? I really need just this last thing, all the hard stuff is done.

If it's an older AT psu you only need to attach something to it like a fan.I doubt that your leds will be enough to power on the unit.
And if it's an ATX (usual ones) just get a piece of wire and connect the green wire with a black.
You can screw the ps unit under the your table and extend the wire from the on/off switch closer to where you sit, or a cool switch on the table

Btw you're not retarded, everyone asked this Q once in their modding life

Cool pic, Kobalt. Amazing.

Thnx, that's an old pic from about 2 years ago.The best compliment i had back when i had it that way was psychadelic hamster cage loll and it was ment as a bad remark lol
Sorry off topic again

Hey guys. Thanks for the help! I did that power supply trick and it worked. I kinda messed up my calculation... (alot actually) I connected 10 LEDs to the 12v lead thinking since they each drain 1.2v that would work just right... my dumbass didnt think right cuz I ran them in a parallel circuit so they all took 12v from the line. they all blew up... I know my mistake now and just need a 470ohm resistor and to take the power from the 5v lead... Im doing that tonight and will get a pic as soon as Im done... although I still dont have the plexiglass to cover it with.

nuttin like a lil led explosion to ruin your day lol but yeah that is a cool idea and good luck with it

Thanks. And yah it did ruin my day, and tonight also, I wasnt able to go buy more LEDs... It will have to wait till tomorow.

Actually a 470 Ohm will need the 12V (for each one) as i said, it works best if you solder a 470 Ohm to each pos.(that's positive you twisted minds) and send 12V up the main wire

I have a question concerning the use of resistors and the 5V line. When you purchase LEDs from a store for use in a computer, they often come with molex plugs attached, so they can simply be connected to the regular power supply. I have several such LEDs in my computer, and they have been running for a couple of years without any issues. Why then do you advocate using resistors?

Thanks.

you can get led's with internal resistors... common values are 5v and 12v leds... they are more expensive and the selection of colours (e.g. blue, white, uv, violet) and the brightness is limited...

And regular leds that dont come with res built in, you can get for a fistful of rice lol so does resistors
This guy is the best for leds, i always buy mine there. The more you buy the less it cost. The 5mm ones are the same you see everywhere for $2 even $2.50 a single led and there in some cases the res is free
http://stores.ebay.ca/BestHongKong

As an example these UV ones 50 units for $15 what more do you want, free shipping? IT IS lol
http://cgi.ebay.ca/UV-LED-50-x-Ultra-Viole...oQQcmdZViewItem