Hey, so my first project is to make a 3d LED Cube:

I saw an 8x8x8 somewhere online, and thought I'd make a 4x4x4. I found a how-to at:

http://www.instructables.com/id/LED-Cube-4x4x4/

And got excited, and began to build: .jpg) until: but:

I think I have a problem... I had the marquee project in the back of my mind, but didn't think about using the reverse-voltage effect.

The way that the 4x4x4 cube is set up is: Each layer's LED cathode is connected. Each Column's LED anode is connected.

This gives me 16 anode connections, and 4 cathode connections... 16+6=20,

but there are only 17 I/O pins on the MCU. It took a bit to get this together and I'm trying to be lazy and not de-solder the entire thing.. any ideas?

Please take a look at 74HC164 datasheet. This could help you use 2 pins of your micro controller to control 8 different things. You could possibly use more than one to achieve what you want.

Update!

So here is the video of my first test... I purchased the 74HC164, but haven't got it set up yet. As for the programming I just used the LED Marquee, but since I have only 17 I/O pins to work with, that only gives me 2.75 rows.. more videos with updates, and a tutorial and code will come when it gets done.

Youtube Link

Very nice. Let us know when you are done with cube.