I have a request, I am a therapist in Slat Lake City, Utah and I am looking to make a light-bar for my clients. It looks similar to the video attached (TI MSP430 Launchpad + 74HC595 8bit Shift Register - YouTube) and would need to upscale it so it would be about 30 inchs wide. I would also need to be able to control the speed of the light moving back and forth. The ultimate product would look like this but hopefully cost much less
Some questions come to mind:
You would make the box & diffuser cover or something for the front of it?
How densely spaced do LEDs need to?
Any particular color LED?
How bright?
Good lord! Have a look at Neopixels. You could do the hardware in 5 minutes.
These are NeoPixels : Dragon video.
For something your size it would be an arduino, 3 wires and about 10 lines of code.
-jim lee
What everyone else said - neopixels are the go. You can fool with shift registers if you want to fool with shift registers - they're fun - but if you are looking to build something, then neopixels. Buy a 30 inches (I think the minimum is 1 meter) of the expensive strip - it's expensive because it is densely packed with LEDs.
To make it go, use the neopixel library. Plenty of examples.