With neons, cold cathode and EL lights making their rounds in cases, we probably overlook the cheapest and easiest lights to use, LEDs. Light emitting diodes (LEDs) are about as common as screws in everyday life. They are in a lot of electronics we use and they provide visual help in all sorts of environments.
So how do these tiny workers exactly funtion? You can think of them as just tiny light bulbs, but without a filament. Because there is no filament to warm up, LEDs are less prone to burning out and emit very little heat. The actual light emitted is caused by electrons moving rapidly. For more information on the history and a more scientific explanation, check out LED Museum. There's a ton of information there of LEDs past and present.
What I have here is a 5mm, 3.7V, 3200mcd (millicandelas) blue LED (thanks brutal!). The mcd rating is just a brightness rating, the higher it is the brighter your LED will be. On most LEDs you buy, there are leads that come out from under the plastic dome. One end would always be longer which tells you that it's the anode (+). The shorter one is the cathode (-), this helps in wiring up your lights correctly.
Before we go ahead and start replacing LEDs all over the place, I'm going to setup a quick test station for my LEDs. Here's what you need:
- Any HDD plug from a case
- LEDs (blue is always nice, but more expensive)
- Solder/Electrical tape
- Molex connector
- 100ohm, 1/2W resistor
- Soldering iron (optional)
I ripped this plug off a old case, any of these holders will work. I prefer the two pin variety since I can just plug the LED in directly, we'll get to that in a bit.
When you get a hold of a molex connector, you want to make sure you are using the 5V line (red). I had this extra molex with a yellow wire, so I just flipped it around and put it into the 5V line. Confused yet? : )
If you want to use the 12V line, you're going to need a different resistor (~300ohm) or so to prevent your LED from exploding. I'm going to use the 5V line along with a 100ohm resistor to get things going. You always want to get the right resistor in conjunction with what voltage your LED is rated at. If you're not mathematically inclined as me, you can always go over to brutal's resistor page to calculate your needs.
Here's my simple wiring scheme, I have the resistor on the 5V line which connects to the HDD holder I ripped apart. The other line is for ground, wire accordingly. Wrap this up and you are set to get things lit.
Just shove the leads into the HDD LED holder you ripped out and we're ready to go. Make sure you are plugging in the correctly, the long end is + while the shorter is - . Here's what you should get after plugging in your molex and powering it up:
The last picture is the LED shining on the wall, looks a lot better in person. Now that we have the jist of wiring stuff together, lets start replacing everything we can get our hands on. By the way, you most likely won't need a resistor when replacing the LEDs in your case and so forth, there's usually not that much voltage running through to your existing LEDs that will pop your replacements. Let's start...