Build a LED Cube 4x4x4 in Less Than 3 Hours

I was always wanting to build a LED cube for my wife (as I promised her to). I've been watching a lot of tutorials/instructables about building a LED cube and frankly speaking, all of them have the same method to build the cube. That is: bending a LED leg and soldering it to the other LED. That works, but it takes time and a lot of adjustment to get it right (I mean beautiful). The end result is that we still have the cube but it's not like what I've expected. So I checked around and found this design is awesome:

http://www.robotshop.com/en/programmable-rainbow-4...

SO I think why don't I do something like that. I got the schematic from the site, everything looked promising but I can't send it to manufacturing because of its special design and low volume (I'm located in Vietnam so not everything is doable here). Therefore, I had to start off with single-color LED only and asked a CNC shop to mill it for me (of course, 1 sided-PCB only)

Step 1: Schematic

This is the schematic I wired up for my 4x4x4 cube:

-LedCube4x4x4: all cathode pins are connected (common GND)

-GroundingPlane: the base board where you have all the header to connect to micro controller board (I use Arduino Uno). I have 2 8-male-pin headers for 16 columns and 1 4-male-pin header for row control (active LOW)

Step 2: Components

You will need to have your 5 PCBs ready and few extra things:

Solder kit: solder station, solder wire, solder lamp
20 straight steel wires (1mm diameter, equivalent to AWG 18, I use google for this conversion)
Of course, 64 super bright (or diffused, your choice) 5-mm LEDs

Step 3: Soldering and Connecting the Cube Planes

1. First, solder all 16 LEDs to 1 cube plane PCB. Please notice all connected pins are cathode pins (please check carefully on the bottom side of your PCB) and the spacing is not very wide; therefore, solder carefully and avoid bridging.

Second, continue with your next cube plane and finish off the rest of 2 planes.

Each plane costs me around less than 5 minutes to build (take time to practice though).

Test each LED with a coin battery to make sure all LEDs work before moving to next step.

2. Next, connect all planes together. You will need to be very careful and make sure the alignment is done well. Otherwise, you cube will be tilted after you finish. Remember 20 straight steel wires, make sure they are straightened well.

I don't have the alignment jig for the steel wires when I solder them to the plane PCB, just visually check.

Let's start with 2 wires at diagonal corners. Then i put the second layer into 2 wires I use one LED leg as a SPACER (see photo) between layers. Solder the second plane.

Next is to solder 2 more wires at the other 2 corners.

Next is the third plane into 4 wires

Next is the fourth plane.

Notice, I only use 4 wires (no more) because it will help the alignment easier and also it's easy to put your layer in. Imagine, you have to align 16 wires to fit in 16 drill holes on your plane board. Aww, it'll drive you nuts.

After that, fill in the rest 12 columns, inside out.

3. Some notes:

-Avoid bridging when soldering the steel wire

-Start soldering 4 columns at the corners, then 4 in the middle, then on the side. By doing this, it will allow some space for you to solder

-Test each LED after finishing the column parts

Step 4: Connecting the Ground Plane

This step takes time to align 16 columns to 16 drill holes on the ground plane. You have to use another LED leg as spacer to align all 16 columns. Do it slowly, solder 1 by 1 and adjust accordingly

Once done, solder 3 header arrays.

Did I forget something? Yes, that is the common ground connection of 4 layers. There is extra 1 drill hole on each plane is for the common ground connection. Remember I told you to prepare 20 wires, not 16 :)

Please see the picture with 2 red circles. They're the plane ground. Notice that, I don't connect that drill hole to any pcb trace. This is to allow you to put the wire through layer without shorting them, at the same time, improve the tidiness of the cube :)

Step 5: Final Touch & Connecting the Arduino

After completing all the LED and wire assembly, you can add 4 standoffs to the corners to make the cube even nicer. That's why you see 4 big drill holes at the corners.

Almost done, now you can connect your Arduino and start programming. There is tons of tutorials on how to do the programming so I won't talk about it here.

You may notice 2 extra small boards that I have in the photo sections. They're tiny handy 75HC595 shift registers which help reduce significantly your Arduino pins. You will only need these 2 guys if you're using Digispark Arduino. It has very minimal amount of pins so you can't connect directly to the cube. Refer to this link to know more about Digispark: http://digistump.com/wiki/digispark?redirect=1

Voila, here is the video link. It may be not the best but just prove that the cube is working: