tomriddl3:
hey sorry for bringing this post backquick question.. i order the wrong type of LED's (common cathode) .. and i soldered as specified in this instructable http://www.instructables.com/id/4x4x4-RGB-LED-Cube/ ... how hard and what can i do to convert this from a common anode to a common cathode cube??? any help would be greatly appreciated .. even if anybody can just point me in the right direction.. thanks!
If you want to use the TLC5940, you will need to use common anode LEDs. If you want to use common cathode LEDs, then you will probably want to either use shift registers and a whole lot of resistors, or charlieplex the LEDs. Another option is transistors. I have a cube that uses 20 npn transistors, and 20 resistors, and 64 common cathode RGB LEDs.
I have an unfinished website linked below with the details.