How to Build a Simple LED Cube 4x4x4 - Part 4

Software
The software is derived from my earlier LED cube, the charlieplexed version. Of course the "hardware layer" had to be changed, because physical control of the LEDs is different. But the rest is very similar.

How to Build a Simple LED Cube 4x4x4 - Part 3

Connecting the Electronics
There isn't much, really. First, solder the microcontroller's socket to the perfboard, then the socket of the driver. I didn't use a socket for the driver initially, which I regretted later...

Here is a schematic.

How to Build a Simple LED Cube 4x4x4 - Part 2

Building the Cube Structure

In part one we prepared all LEDs for the assembly of the cube. Now, we start in earnest...

How to Build a Simple LED Cube 4x4x4 - Part 1

Project Features

• Easy to build
• Only two active components (apart from the LEDs, of course)
• Includes detailed build instructions, schematics and software

Introduction
When I posted my charlieplexed 4x4x4 LED cube I did so in order to show an alternative implementation for such a cube. Its unique feature is that it only uses 9 controller ports. For some reason it gets a lot of interest from lots of people. And I had quite a few requests for schematics because people wanted to build it.

The problem with it is that it is only simple in terms of hardware requirements. But it is relatively complicated to understand its structure. So I thought I should try my hands on a really simple, easy to build LED cube and write a post including build instructions for people with basic skills in electronics.

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.

A Charlieplexed Knight Rider Light

Features

• Low cost and low part count
• Four different flashing patterns, easily modifyable
• Speed control and pattern switching via pot

Introduction
This is nothing special, really. "Knight Rider lights" or "Larson Scanners" seem to be very popular microcontroller projects. I guess they are the next step right after the blinking LED (a.k.a. the "Hello World" program for microcontrollers).

I was recently asked if I could draw a schematic for such a device and in the end I decided to actually build the circuit. That way I could turn it into a blog post and make it available to a wider audience. The other point was that I could get my kids involved in building this.

This version is not exactly a beginner's project, because the charlieplexing is quite complex and turning the schematic into wiring can be a little confusing. So perhaps it is a good project to improve your soldering skills.

The Charlie Cube Mark II: 4x4x4

Project Features

• Minimal hardware
• Wiring more complex than standard led cubes
• LED duty cycle 1/8

Update: There is a schematic and part list available here.
 
WARNING: Do not build this cube unless you know what you are doing! It uses minimal hardware but is difficult to understand.

There is a new design which is much easier to build with a very low part count.

Introduction

When I had finished my first charlieplexed LED cube (3x3x3) I wondered whether my next project should be a 4x4x4 cube. But at the time I thought it wasn't worth the effort. After all, I had just shown that a charlieplexed cube is possible and that it can be done with reasonable effort.

The 4x4x4 would of course have 64 LEDs, which would mean quite a lot of soldering. And since I would definitely want to use bright wide-angle LEDs, it wouldn't come cheap.

But the idea never really went away and when I found a good offer for a set of 100 suitable blue LEDs I simply couldn't resist.

Musings on Charlieplexing

Some time ago I stumbled over an article about charlieplexing on hackaday.com. Charlieplexing is basically a method to control n * (n-1) LEDs using only n I/O ports of a microcontroller. Say you have 5 I/O ports, then you can control 5 x 4 = 20 LEDs independently! Find more details in Wikipedia. I was fascinated, because I had never thought it was possible to control so many LEDs with so little hardware.

But it seems that charlieplexing comes with a few drawbacks. While this is certainly true, some of these drawbacks are in my opinion over-emphasised, especially when compared to "conventional" LED multiplexing. So I set out to explore the issue, just for the fun of it.