The Charlie Cube Mark II: 4x4x4 - Update

Update
Build this simpler version instead!

Introduction
When I wrote my post on my charlieplexed LED cube, I never meant to publish build instructions. There are plenty of instructions around and a regular LED cube is much easier to make.

Instead, I wanted to show that it is possible to use charlieplexing for such a cube. And I wanted to share my thoughts on how I got there. So I never published schematics for the cube. Also, it is relatively difficult to draw a 3D electronic structure on a 2D schematic.

But quite a lot of people asked for a schematic. So in the end I just tried my best to draw it in an understandable way. I still think that for someone with some basic knowledge of electronics it is better to try to follow my explanations in the original post. But anyway, here it is.


Components
But let us start with the components first. Here is a list. 

• 64x LED, blue, ultrabright, wide angle
• 8x 1k ohms
• 8x BC337-40
• 1x Atmel microcontroller ATtiny24 (or better ATtiny84 with more memory)
• 1x perf board

The list is very short, perhaps that is why there is so much interest?

The Groups
 In order to avoid overloading the schematic I am using a sub-circuit, which I call a group. This is just a set of 8 LEDs. All anodes of those LEDs are connected and the LEDs form a structure of 2x4 LEDs. See the original post for an image. I used those groups as my basic building stones for the cube.

And here is the (trivial) schematic of a group:

It has 9 connections: 8 LED cathodes and 1 common anode. 4 of these groups are stacked on top of each other to form half a cube.

The Cube
And here comes the rest. In the upper half of the schematic I tried to show the 8 groups in a 2.5D fashion. And at the bottom there is the controller and the driving transistors - one for each group. The image is rather large. It is best to click on it to get the larger version. But it seems that even then, the blog reduces the image in size. So I will put it on my download page.

So there it is. The full schematics of my cube. I hope it helps at least a few people. But I am not so sure...

What's next?
My feeling is that the low part count of my cube is what gets people interested. But the fact that I am using charlieplexing means that it is really quite difficult to understand, especially for people with only a basic knowledge of electronics.

So I decided to build a really simple LED cube. It will have a very simple 4x4x4 LED structure and use only 2 cheap active components (apart from the LEDs of course). And I will write a post with detailed building instructions. LED cubes for the masses! :-)

Stay tuned!