I discovered an easy way to diffuse these LEDs without permanently modifying them.
Cut a small square from the tough white foam Sparkfun ships with ICs and IC sockets. Then with an X-Acto knife, cut a small X in the underside of the cube of foam, being careful not to cut all the way through to the top. Then with scissors round out the sides and top of the cube. Stick the LED into the X you cut into the foam, and now you won't have the spotlight effect!
If you want to go back to the clear LED, just remove the foam piece.

I love these things, they're deadly awesome.
Exhibit A:
RGB LED Test Drive via Arduino from James Snell on Vimeo.

I bought a couple of these for fun. I hooked it up to the PWM channels on my microcontroller, and output a sine wave of slightly different frequency to each colour channel, and it projects a really neat cycling colour pattern on the roof when I turn the lights out! I posted a demo... kinda hard to see with my webcam, but you can see that it works.
http://www.youtube.com/watch?v=2Rm2VQqJ2tk

I'm making a PCB with eagle... I did not find them in it.. any ideas?

I'm wondering how bright these are. Like could you clearly see them from 40 feet away in a well light room?

Yo soy solo un pobre esposo. me pueda Por favor comprar algunos de la electrónica de la estos. Pero no no por en la de estos caro mucho precios. la precios tienes entiendo su tienes son loco..

Te necesitas entiendo yo solo necesito un poco de estos y yo no tengo much dinero. Te necesita entiendo también muchas personas no tienen mucho dinero lo mismo. Pregunta.
¿qué tienes? ¿Qué deseas? El mundo en tu bolsillo

Yo tengo un esposa y cinco ninos todo lo que quieren es estudiar electrónica. Si usted no puede ayudar a mi esposa tiene solamente una opción. Ella debe trabajar un trabajo un muy indeseable posición para proporcionar el total de la familia con una vida mejor.

I'm driving my RGB LEDs with two shift registers (74HC595) from an Arduino Uno. After playing with some potentiometers, I found the following resistor values to offer the best color balance and highest contrast: Red: 430-Ohm, Green: 910-Ohm, Blue: 750-Ohm

Another tip that would have helped me: These LEDs are the "clear" variety (meaning they have a spotlight effect.) Sparkfun also sells "diffused" RGB LEDs. These LEDs have a much softer glow.

I found the right one, but what's up with that other one with all 4 pads all touching each other? Isn't that a short?

Need the little cheap black plastic panel mount LED holders. Sparkfun?

I don't see this in the Sparkfun's Eagle library. Is it there somewhere?

That didn't work as nicely as anyone might hope. You can get them from here once the mirror updates in a few minutes: http://www.gedasymbols.org/user/russell_nelson/RGBLED3.fp http://www.gedasymbols.org/user/russell_nelson/rgbled.sym

I made a symbol and footprint for gEDA. http://geda-project.com/ Remember that a symbol file can't have any blank lines, so when you edit rgb-led.sym, make sure you haven't added a blank line to the end (like I did). ---------------------symbol---------------------- v 20100214 2 P 0 500 200 500 1 0 0 { T 150 550 5 8 1 1 0 6 1 pinnumber=1 T 150 450 5 8 0 1 0 8 1 pinseq=1 T 200 525 9 8 1 1 0 0 1 pinlabel=R T 200 500 5 8 0 1 0 2 1 pintype=pas } P 900 500 700 500 1 0 0 { T 750 550 5 8 1 1 0 0 1 pinnumber=3 T 750 450 5 8 0 1 0 2 1 pinseq=3 T 725 525 9 8 1 1 0 6 1 pinlabel=G T 700 500 5 8 0 1 0 8 1 pintype=pas } V 450 450 300 3 0 0 0 -1 -1 0 -1 -1 -1 -1 -1 T 800 900 5 10 0 0 0 0 1 device=LED L 516 803 617 904 3 0 0 0 -1 -1 L 617 904 621 855 3 0 0 0 -1 -1 L 621 855 722 957 3 0 0 0 -1 -1 L 484 718 585 818 3 0 0 0 -1 -1 L 585 818 589 769 3 0 0 0 -1 -1 L 589 769 690 870 3 0 0 0 -1 -1 L 300 575 300 425 3 0 0 0 -1 -1 L 375 500 300 575 3 0 0 0 -1 -1 L 375 500 300 425 3 0 0 0 -1 -1 L 375 575 375 425 3 0 0 0 -1 -1 L 600 425 600 575 3 0 0 0 -1 -1 L 525 500 600 425 3 0 0 0 -1 -1 L 525 500 600 575 3 0 0 0 -1 -1 L 525 425 525 575 3 0 0 0 -1 -1 P 400 900 400 700 1 0 0 { T 275 775 5 8 1 1 0 0 1 pinnumber=2 T 450 750 5 8 0 1 0 2 1 pinseq=2 T 400 650 9 8 0 1 0 5 1 pinlabel=K T 400 600 5 8 0 1 0 5 1 pintype=pas } L 200 500 300 500 3 0 0 0 -1 -1 L 375 500 525 500 3 0 0 0 -1 -1 L 600 500 700 500 3 0 0 0 -1 -1 L 450 500 450 650 3 0 0 0 -1 -1 L 450 650 400 650 3 0 0 0 -1 -1 L 400 650 400 700 3 0 0 0 -1 -1 T 800 700 8 10 1 1 0 0 1 refdes=LED? T 800 1500 5 10 0 0 0 0 1 description=RGB LED with common cathode T 800 1300 5 10 0 0 0 0 1 numslots=0 T 800 1100 5 10 0 0 0 0 1 symversion=0.1 L 375 300 525 300 3 0 0 0 -1 -1 L 450 300 450 200 3 0 0 0 -1 -1 L 375 375 525 375 3 0 0 0 -1 -1 L 450 375 525 300 3 0 0 0 -1 -1 L 450 375 375 300 3 0 0 0 -1 -1 L 450 500 450 375 3 0 0 0 -1 -1 P 400 0 400 200 1 0 0 { T 270 125 5 8 1 1 180 6 1 pinnumber=4 T 450 150 5 8 0 1 90 8 1 pinseq=4 T 375 325 9 8 1 1 180 0 1 pinlabel=B T 400 200 5 8 0 1 90 2 1 pintype=pas } L 450 200 400 200 3 0 0 0 -1 -1 -------------------------------footprint------------------------ Element(0x00 "LED, size in mm (pin 1 is +, 2 is -)" "" "LED5" 100 70 0 100 0x00) (

typical LED is 0.5 mm or 0.020" square pin. See for example

http://www.lumex.com and part number SSL-LX3054LGD.

0.020" square is 0.0288" diagonal. A number 57 drill is

0.043" which should be enough. a 65 mil pad gives 11 mils

of annular ring.

Pin(-75 0 45 30 "1" 0x101)
Pin(-25 0 45 30 "2" 0x01)
Pin(25 0 45 30 "3" 0x01)
Pin(75 0 45 30 "4" 0x01)

ElementArc(0 0 118 118 0 360 10) ElementArc(0 0 138 138 0 360 10) Mark(0 0) )

I know this is a common cathode RGB LED

Watch out for the 2V color.

I got one these from a different kit vendor but it looks exactly the same. The trouble is that for the life of me I can't get red to light. I'm assuming it is just a defective red element. Has anyone else experienced this?

Wired one of these up to my Arduino. I didn't have a 180ohm resistor, so I wired 2x 100ohm resistors in series instead. Seemed to work just fine, though, I would strongly recommend looking at the diffused version, as you can see the distinct RGB channels in this one if you don't use a good diffusing material. That said, this thing is incredibly bright. My eyes... so shiny...
Anyways, for a couple bucks, it was neat for a short while. Get the diffused one, and the amusement becomes a lot more useful.

I'm having trouble trying to turn the red and blue at the same time, is this supposed to happen?

Has anyone ever tried to use these as RGB sensors? In photovoltaic mode, I seem to get reasonable voltages at R and G, but nothing at B whatsoever...

I see that the current data sheet shows pin 3 as green and pin 4 as blue but the pads in the SFE Eagle Library part appear to be labeled incorrectly for the post 1/2010 parts. The pads from left to right are labeled RED, GND, BLU, and GRN. Is this an error in the Eagle package for the part or am I missing something?

5mm T1-3/4 RGB LED's are 4-pin with 0.05" spacing, for square 0.028" pins (x1.414) use a 0.040" hole size

Before I get a few of these for my projects, can I simply mix the colors as-is? Or do I need to switch between colors every couple of milliseconds with a timer to give the appearance of being a mixed color? I really don't want to have to learn this the hard way...

I'm using these in my Arduino projects to give visual feedback when there's an error; similar to the xbox 360's "three rings of death".

I created a video showing these LED's in the 2x2 silicone button pad. In my opinion, the diffused LED's are not necessary:
http://www.youtube.com/watch?v=h3lqukVX8CI

I know this is a common cathode RGB LED. Does anyone know where I can get a common anode version of this LED? I would like to use NXP PCA9531 PW (8-bit I2C LED dimmer) to control the RGB LED as in the Application notes from nxp.com Page 6 and 7 >> http://www.nxp.com/acrobat_download/applicationnotes/AN10315_1.pdf .

In order to diffuse the RGB channels properly you need to sand the LED
This is helpful
http://www.instructables.com/id/how-to-defuse-an-LED/

I can't find this in the SFE Eagle Library either.

I couldn't find this on the SFE Eagle Library, does anyone know what it is called?