Building LED Floodlights?

[ricc0luke]

So I went on a tour of the CNN Building in Alanta a few weeks ago, and at the end you sit in this little theatre. In there they had several LED light fixtures that served several purposes. They were the house lights, and they were also used to color wash the screen. They consisted of 3 colors of LED's that you could mix and create any color of light from white to dark purple. My question for those of you good with the small electronics and LED's, how would I build and control a few of these fixtures?

[Inaki2]

Well, there are various manufacturers of LED lighting, they aren't normal LEDs and are relatively expensive to buy "off the shelf". They also generate a fair amount of heat for what they are and they need proper heatsinking, not to mention DMX control hardware/software.
Still, you could go for it considering your knowledge of electronics is good, its not an easy task. LEDs also need either a diffusing plane or some distance to properly mix. RGB isn't instataneous and most LED will have a specified angle.

[ricc0luke]

I was just thinking maybe advoiding DMX all together, and just useing 3 dimmers to mix the colors... I don't know... I just thought it would be an awsome way to light a room in my house...

[Inaki2]

you can't plug LED systems into a dimmer, they don't work that way. They're more like a fluorescent tube in that they work of excitation of atoms.
Some guys at MIT did a floor for their dorm from something like 800 LEDs and ended up costing under $2500, but then again, they're MIT guys. They made their own PCBs and ran it of USB and control it through MatLab. Not simple stuff to be honest. Plus I don't think it was an RGB thing, more of a combination of colored LEDs that looked cool as a dance floor or something.
RGB systems are not easy to create though. Even the professional units have issues.
They're getting cheaper by the second though, you'll be able to buy them soon.

[soundman1024]

Also bear in mind that LED lights are more directional lights than flood lights.