Introduction: 8x8x8 LED Cube Addendum

Just thought I'd like to share some hopefully illustrative pictures that I make along the way as work my way through the 8x8x8 instructable by Chr.

It's a work in progress, and is being updated as I complete the work on my 8x8x8 cube, and find time to do updates.


THIS JUST IN: if you FUBAR anything based on what I write or don't write in this instructable, it's all your own fault.

Step 1: Components

I used the component list from Chr's instructable, and bought everything off of E-bay. I was unsure about some of the components, and I had to do some research before I bought the stuff I needed. I did end up with a bag of 1000 clear 3mm LEDs that I don't really have any use for, but hey, my drawers are full of neat stuff I don't need!

I've taken screenshots from e-bay to make it easier for you to find the components needed for the 8x8x8 LED Cube build. I didn't bother with the capacitors, since they mostly look all the same, and as long as you get the right Fahrad and Volt rating, you'll be good.

Step 2: The Template

I had a slab of shelfing lying about, and used that to create my template. I was a little too eager when I drilled the holes, and they became fairly rough. I recommend spending a little more time one this phase.

I use 5mm LEDs, and drilled 5mm holes that I reamed with a screwdriver that happened to fit really well. I enlarged the holes so that the LEDs fit snugly, but are still easy to extract once the whole layer is complete.

Notice how in the first row all the cathode legs point to the right. In the other rows, all the cathode legs point to the top/straight ahead. In the picture below I was still in the process of figuring this out. In the end you end up with a structure that looks like a comb, like Chr said. That's why you need the bracers - to strenghten the structure

Step 3: Test Cube - Learning by Doing

I decided to build a test cube first, and concluded that a 4x4x4 would be big enough. A 4x4x4 cube is quickly built, and doesn't use more than 64 LEDs. From the 1000 I bought, I can build several 4x4x4 and still have enough to allow for bad components and the 512 needed for the 8x8x8.

I must admit that at first I could not properly envision how the layout of the LEDs would be. I tried reading Chr's instructions several times, but I was still confused. After trying it out for myself, all became clear :D   Learning by doing is a powerful technique, if you can call it that.

Lesson: Bending the LEDs
hold the LED with the notch/flat side pointing to your right, and fold the shorter leg straight forward. The shorter leg is the cathode (negative).

After having built the first two layers, I wanted to stack them on top of each other. Suddenly I realized that I had not bent the longer anode (positive) leg to get around the bulb of the LED above it. It was a little pain to bent the legs after having soldered the first layers. If the soldering is not solid, they might break from the strain of you bending the anode leg.
I'm going to start bending the anode legs at the same time I bend the cathode leg. You'll have to experiment a bit to fint the right angle and lenght for the bend in your own project. I think I need to bend the anode 5 - 6 mm from the top in order to clear the bulb of the LED above.
The finished 4x4x4 cube is somewhat crooked because of this, but the good news is YOU can avoid this. Besides, it's a test cube.

Step 4: Soldering

When you have soldered all the LEDs together, you need to add the bracer to strengthen and support the structure. I found out that it may be wise to find a metal wire that is of similar guage to the LEDs' legs. If the  wire is of completely different guage or alloy, you may have a hard time soldering them successfully together. The thicker wire may need to be preheated. Just try with what you've got and see how it works out. The bracers broke off several times when I was bending the anode legs of the LEDs. In the picture below you can clearly se the brace spanning the four comb-teeth of the 4x4 layer.

Also remember to test each LED after you've soldered them together. Easier to remove a bad one now, then when the cube is finished. Check all LEDs in each layer.

Step 5: The Latch-board

I'm not new to soldering. This is not my first project, and I do recommend that you have destroyed a few things before you try out the 8x8x8 LED cube instructable.

Any how..  the brains. I started out by hunting down my 9x15 cm predrilled, copper eyed boards. Thank you China! You better make sure you're not using a board that has continuous lines of copper eyes, but one that has all the eyes separated.

I placed the components like I saw in Chr's instructable, but noticed that they seemed a little cramped. I figured out that offsetting the components by one line at the top and left side wouldn't do any harm, and would give me a little more room to work with. I also allowed for one line more in between the rows of components. I happily started soldering, only later realizing that I had left myself little space for the 74HC138p-chip and the 20-pin connector. I think it'll be alright, but time will show. I'll update later on this point.

Here's the picture of what Chr's board looks like.

After looking closely, I actually noticed that you NEED a line free at the top for placing a capacitor later on.

Step 6: The Latch Board - Bottoms Up!

All soldering is done on the copper-clad back side of the prototyping board, so here are some pictures of what mine looked like at some points in time.

Step 7: Latch Board Backside 2

Here you can see I've added the "power rails" below the components you saw earlier.

When soldering the long continuous bridges, remember to rinse off the the tip of your iron from time to time. Soon enough the solder will start to stick to the tip, and you'll pull the solder  from one eye to the next, leaving the first one short on solder. Take your time, and buy plenty of solder :D

When you are done, it's wise to use your voltmeter to check that all connections are solid, and that you haven't inadvertently made a bridge where there shouldn't have been one. I made a few wrong connections, and had to use a solder lace to undo my mistakes. Note to self: don't work in poor lighting conditions late at night.

Step 8: Latch Board Backside 3

Here I've added the Vss and GND connections to the 20-pin sockets. As you can see, it's easy to make a bridge between Vss and GND here.

Step 9: A Note on the Kynar Wire

The Kynar wire is pre-tinned and extremely thin. It's still great to work with and saves time not having to tin all the little wires. It can however be a challange to properly remove the plastic jacket to reveal the wire. I found that using an exacto blade was the easiest way to go about this.

I cut the wires to desired length and straighten the pieces a little, before laying them on a flat, smooth surface and gently roll them a few revolutions with the exacto blade. You don't need to use any force at all. Just gently resting the blade atop the wire and rolling it will be enough. You don't need to cut all the way through the jacket in order to be able to remove it with your nails. If you use too much force, the wire will likely break when heated by the solder.

Also you don't need to remove a lot of the jacket. Between 1 to 2 millimeter depending on your soldering skill and eyesight.

For the shorter wires I ended up with a wire length of [have to check this to be sure :]
The longer wires I cut to 6,5 cm, but I think they were a little on the long side. You can probably cut them to 6,0 cm or shorter and still be comfortable.

Step 10: Latch Board Backside 4

I looked closely at pictures of the backside of Chr's latch board, and noticed something smart that they had added during the soldering process. To ease the soldering of wires going from left to right (looking at picture with the power rails at the top) Chr has added an extra row of solder points right next to the 8x1 pin connector row. This gives one point for wire coming from left side, and one point for wire going to the right.

If you look closely at this (large) picture of Chr's board, you can see that they started doing this only at the bottom row.

Step 11: Latch Board Backside 5

When soldering the longer wires connecting the two rows, ba careful to not mix up the wires, and to get the positions right.

As always check connections from first to last point with a voltmeter.

Step 12: Latchboard Backside - Caps and Bridges

I placed the Vss bridges over the GND in this step. You can avoid a lot of work by planning ahead, i.e. BEFORE you get to this step. If you do, you can place the bridges right at the same time as you make the power rails. That will save you a lot of time and solder.
I did not plan ahead like that and had to remove the solder from two eyes, place the bridge and resolder. Didn't take too much time, but still would have been easier to just place them while soldering the rails.

Next up were the capacitors. Like Chr said - use them like candy. I just follow Chr's instructable as closely as I can, candy or no candy.

Step 13: A Little Tip for Not Ruining Your Work

At this point I realised that resting the board on the topside components while working on the backside was getting increasingly risky. Fortunately, in my drawers of nice stuff I don't need, I had a few brass(?) spacers from my days as a service tech.

Step 14: The Latchboards Back Side, Again