I caught glimpse of this interesting project where condoms were used basically as strobe lights that follow music: http://www.metacafe.com/watch/826934/magnum_condom_sound_activated_led/

I am mainly interested in the LED that syncs with the music, the condom I guess is just a bonus. However I am confused as to what is what in this video since nothing is really labeled and has no audio. Can someone give a basic rundown of what is what and what exactly to do from what you can understand?

I have a set of questions really:
- what exactly is that LED with the red and black cables? Is it just a basic LED or a special kind?
- are the cables of this LED connected at the same spot or is each end connected to different ends of the cables of the stripped speaker cables?
- the end of the video shows 2 condoms that glow. How would I connect the 2 LEDs and where do I connect each?
- can I connect more than 2 LEDs?

-- EDIT --
I'm planning on using a cost-effective 2.0 set of speakers. Which would be better? Ones that dont rely on an outlet for power or ones that do?

Forgive the pun, but this is a poor man's "color organ".

"Color Organs" were really popular years ago. All this guy seems to be doing is attaching an LED to the speaker output. He may have a current limiting resistor in series with the LED.

I'd suspect something like this:

speaker output+ ----/\/\/\--->|----,
speaker output- ----------------------'

The /\/\/ is probably a 27ohm resistor. Might have to play with the value to get optimum output while reducing chance of damaging the LED. If the speaker output is too high, the voltage will kill the LED regardless. Might try an earphone jack first.

The --->|-- an arbitrary LED. Do not use the type of "LED" that changes to multiple colors as is provided in some PC power-on buttons. Those are actually multiple LEDs with a power regulator and sequencer built-in to them. However, a bi-color LED might make an interesting choice.

Personally, I wouldn't connect it directly to a mobo or PCI adapter sound card. It looks like this guy may have powered the LED from a separate (and cheap) amplifier.

As long as you have sufficient output voltage, you can put LEDs in series. A red LED requires about 1.4V, green and blue require slightly higher voltages. When you put them series, you add the voltage drops. You can try to put some in parallel, but you'll get unpredictable/inconsistent results. Could be interesting. More LEDs in parallel consume more milli-watts.

However, I would recommend building/buying an amplifier specifically designed to drive an LED from an audio signal. There are numerous hobby circuits out there designed to drive small incandescent bulbs and LEDs.


edit to add-
You may run into a cheap amplifier that has a DC bias on the output, and that might cause problems. Smaller devices like iPods probably won't output enough voltage to power the LED, especially if they have the new output hearing safety features. If you're interested in such circuits, check out hobbyist electronics sites like:

http://ourworld.compuserve.com/homepages/Bill_Bowden/
http://www.uoguelph.ca/~antoon/
http://www.uoguelph.ca/~antoon/gadgets/gadgets.htm

And, a more sophisticated LED color organ,
http://www.electronicpeasant.com/projects/ledlamps/ledcolor.html

pre-made sound-amp version for cold-cathode lamps
http://www.ncix.com/products/index.php?sku=11725&vpn=SND-SENSOR&manufacture=Sunbeam

Very high tech, indeed. Though, it's more interesting to see a condom double as an electrical generator, using Faraday's induction to convert mechanical energy into electricity. With the ever rising energy costs, it's not a bad idea to save a few Watts by generating it yourself (or with the assistance of your love partner). Good for the environment, too. Probably enough to recharge your cell phone.

I'm planning on using a cost-effective 2.0 set of speakers. Which would be better? Ones that dont rely on an outlet for power or ones that do?

LMAO! It's pretty funny to see condoms used like that. Behold the condom mod speakers.

Depends on what's driving them. If a decent amplifier is driving the speakers directly, then non-powered quality speakers will work find. However, with some amplifiers you may find that driving non-powered speakers at decent volume results in extreme audio distortion.

If you have a low-power audio output on the PC, powered speakers are virtually a requirement. Again, quality/brand of speaker will make a huge difference in sound. (e.g. Labtec v. Noname-tec)

If you're considering portable use, then look into powered speakers that can run off either batteries or using an AC adapter. (or, if the speakers have an external DC power plug, make your own DC power-pack using a battery holder)

High tech? I think not. I've seen this type of thing since the 1950s jukeboxes.
Is it kind of funny, yes, but high tech, never.

Gerritt