Build your own LED matrix

Hey just, I want to build my own LED matrix using a rainbowduino. Should I use resistors for each LED (to limit the current) or is this not needed?

regards
michu

I’m also interested in this topic… I have dealextreme.com/details.dx/sku.14963 it’s rgb led stripe with 150 led’s with resistors working at 12v and I’m planing to cut each led (128 of them) and use them with 2 rainbowduinos that I bought recently. Im planing of building frame 2m by 1m with frosted glass and led’s behind…

No resistors are needed, the constant current circuits on the board limit the current through the LEDs.