LED Cube and Arduino Lib

There are other Instructables about building LED cubes, this one is different for several reasons:

1. It's built with a low number of off-the-shelf components and hooks up directly to the Arduino.
2. A clear, easy to reproduce circuit diagram is provided with plenty of photos.
3. A unique approach is used for the software which makes programming the cube easier and more expressive.

Parts needed:

-   1 Perfboard
-   3 NPN Transistors (2N2222, 2N3904, BC547, etc.)
- 12 Resistors (~220 ohms and ~22k ohms)
- 13 Headers (male or female)
- 27 LEDs
- Jumper wires

Step 1 Prepare the LEDs

This step largely follows the LED Cube 4x4x4 but we'll be building a 3x3x3 cube instead. A cube of this size is about as big as it gets without introducing additional circuitry and complexity. We'll need a total of 27 LEDs that will be grouped into three sets of nine.

Each set of nine LEDs will share a common connection amongst their cathodes (negative leads). I'll refer to each of these sets as a "level". Each of the nine LEDs on a level is connected to the corresponding LED on the other two levels through their anodes (positive leads). These will be referred to as "columns". If that didn't make sense it will become self explanatory as we build the cube.

To start we'll use a drill to create a jig out of a small piece of scrap wood. The jig will hold the LEDs in place while we solder them. I decided to space the holes around 5/8 of an inch apart (~15 mm) but the exact distance isn't critical. The hole should have a tight fit around the LED since we don't want them to move around while soldering.

Once the jig is done we're going to bend the cathode of each LED in a 90 degree angle. The cathode is identifiable in three ways: 1) It's the shorter leg, 2) It's on the flat side of a round LED, 3) it's connected to the larger piece inside the LED. Make sure you bend the cathode in the same direction for all of the LEDs.

Now we're ready to begin soldering.

Comments

[ryanprocter]

also the only jumper wires i can find are breadboard jumpers. are these ok or are these completely wrong?

[gzip]

Breadboard jumpers are fine but a spool of wire (or even salvaged wire) is just as good.

[ryanprocter]

Hi im completely new to all of this and would like to know what board i need to buy. would this work with an arduino USB UNO?

[gzip]

Yes, any Arduino will work.

[aus151]

I'm plugged into Pwm pins 2-10 for columns and 11-13 for levels, it looks great but not like the video. any pointers for a noob? It took 3 prototypes before i came up with a cube that was perfect. All my leds are hitting my output pins with perfect resistance.

[4eyes12]

Made the cube and uploaded the script, but I'm having a technical issue. My bottom center led in the cube will not function in the arduino routine, but is perfectly functional when tested with a battery... dose not seem to be a connection problem as the two leds above it still function. Any advice or ideas??

[4eyes12]

Forgive me if I missed something but it would be nice if you posted a picture or a list of what headers from the cube pcb are connected to which pins on the Arduino. Other than that good tutorial, thank you!

[Duncan Stewart]

I built my cube a couple of months ago and am only now getting back to trying it out. Should I be able to upload the library and run it, or do I need to reference the library in a separate sketch?

When I try to upload the library directly, I get the following message:
avrdude: stk500_getsync(): not in sync: resp=0x00

Thanks!

[gzip]

That's a hardware problem, likely nothing to do with the cube. Make sure you have the right board and port selected in the Arduino software. If that checks out then you might try a different USB port since sometimes the board can't get enough power.

[Duncan Stewart]

Cool! It was the com port, apparently (though I also added external power AND switched USB ports, so there's a distinct lack of scientific method here.)

Thanks!

[sromero3]

Hello, I need help please.
In the video (which is the LED cube example) you can put only one LED on the third level, without the need to turn off the rest of the column, the second 4 of the video you can see. Is it possible with Arduino?
How I can do?
My question is because when I try to do, for example, just turn on the LED Level 2 column 4 and the LED Level 1 column 5, the LED on the level 1 column of 4 lights also because the level and column are on

[gzip]

The levels are multiplexed. That means only one is lit at any given time but the cycle is so fast that it looks like multiple levels are lit at once.

[sromero3]

Thanks a lot, I will try to do with MUX!! Do you have pictures or more information about that?

[sromero3]

sorry for a new cuestion! maybe the only problem that i have is wen i try to turn of only one led when i have the rest in on!! Can you help me with your code?

[blinkyblinky]

I lost track. which Arduino pin goes to which transistor? I did some probability and found I could have 6 different possible ways of doing it. Can you please specify?

[gzip]

The example is configured (from bottom to top) as:

byte levelPins[SIZE] = {11,12,13};
byte colPins[COLS] = {2,3,4,5,6,7,8,9,10};

[blinkyblinky]

Thanks. So the top level is pin 11 is the top level, pin 12 is the middle level and pin 13 is the bottom level?

[gzip]

Vice versa on 11 and 13.

[mastercheefryu]

Im getting some problems, the arduino 1.0 version doesnt have the sketch folder so where should i place it? directly to libraries? Im doing that but its not working. These are the probs im getting:

ledcube.cpp:1:21: error: LedCube.h: No such file or directory
ledcube.pde:-1: error: 'LedCube' does not name a type
ledcube.cpp: In function 'void loop()':
ledcube.pde:-1: error: 'cube' was not declared in this scope

Plz help me

[Cloudhail]

I unzipped it to the library folder then i unzipped it to the examples folder. in the actual arduino script editor you have to go to the sketch tab (up top) and IMPORT LIBRARY!!! select ledcube. once that is imported I went to the file tab(uptop) and loaded ledcube. with all of that done I hit upload and It works now. Does this make any sense?

[gzip]

You don't need to unzip to the examples folder separately since the examples under libraries will get picked up automatically. Sketch > Import Library > LedCube is only needed for a brand new sketch. That will add #include <LedCube.h> to the top of the sketch.

[Cloudhail]

This is correct, sorry for the extra step. However the import library is a must. This will give you the error if you don't load the library. It took me a little bit to figure that out.

[gzip]

So even with the included example you need to import library before it compiles correctly?

[Cloudhail]

Yes

[gzip]

That's strange. I wonder what's going on there. Is the #include missing to begin with and then the import adds it? I tried downloading the zip and extracting it fresh but couldn't reproduce. I unzipped to libraries in my sketchbook and then to the main libraries folder. Both worked. What version of the Arduino software are you using and on what OS?

[Cloudhail]

Sadly I'm still on vista (I'm a Mac) I'm using the UNO, and yes it does put the #include tag into the top of the script. It's working for me just fine. But this is the way I got it to work. I just figure if anyone was having the same problem as me I could share. Is this not supposed to happen? It may help to know that I start the editor program up without anything loaded at all. (just double click the arduino symbol icon) then I do what I mentioned before.

[gzip]

And you're using the Arduino 1.0 software or older? I'm on Linux (Ubuntu) with 1.0 so I'll try Windows as well (but all I have is XP). You shouldn't have to import the lib for the included example but maybe some combination of software is causing problems.

[stewart_14]

Did you ever get this fixed? im having the same problem!

[gzip]

The sketchbook folder should be created automatically under your home directory when you open the arduino software. The exact location will vary according to OS. You can create the libraries folder there if it's not already present.

Another option is to add the library to the main libraries folder (which is in the same folder as the arduino executable). It's just a less flexible location since you'll have to move any libraries that you've added there the next time you upgrade the arduino software.

Either way you should find the example under File > Examples > LedCube > ledcube if you've set everything up correctly.

[stewart_14]

Did you ever get this fixed? im having the same problem!

[stringstretcher]

I'm experimenting with the routines and find that one column doesn't light up properly in the routine //columns in and out. I have been looking at the cpp file but can't find out what the problem is. Has anyone else seen this? Any ideas? The cube works perfectly otherwise and I love it! Also, the routine you supplied here is not the one featured in your vid is it? Mine doesn't follow these steps!

[gzip]

It's the same routine, the video just starts somewhere in the middle.

[stringstretcher]

I'm sorry, but I beg to differ! My cube doesn't look like this... maybe it's the nut holding the wheel? (me)I'm wondering it there is a bracket missing, which would exclude some of the routines in my sketch. I see some of the sequences, and they should. I will post a vid link so you can have a look. We might learn something! I don't know enough yet to figure this out, hence the questions. Can you point me anywhere to learn more? Thanks for taking time to answer, this is a great little cube and I have had o much fun showing it to my friends. If anyone is interested I will post my revised code, gives a little variation to the cube's appearance.

[alsetalokin]

I fixed even more of the software, and added a few new patterns. There does seem to be a bug, maybe in the hardware, concerning the writing of the buffer using a 128-slot byte array, or rather vector ... which winds up having some crazy values inserted in it somewhere between filling the array with all zeros and writing it to the buffer, which winds up lighting a few lights incorrectly when the buffer is written to the active pins.
The performance of the pattern select button interrupt is still a bit flaky and annoying but overall there's improvement.

http://205.196.120.174/bz76g4wwdkpg/rqi7xkzmjc0yzlg/AlsLEDCube4x4x4Bv2.zip

The other link below has been removed, and the Version 2 really is better, so if anybody actually downloaded the first version, please dump it and use V2 instead.
Thanks for a great time waster !!
--Al

[gzip]

Thanks for sharing this. Maybe I can get my memory management in order enough to declare the arrays dynamically so that the code can support any number of LEDs. Your diff is helpful for identifying the places which need to be updated.

[fobia]

Finally I finished! thanks you so much for all the info in this site.

[adumas]

Hi... I just built this and have a couple of questions...  I tried using the transistors but the LED output intensity was minimal. I bypassed the transistors and when directly to the output pins (which I declared in the pde). That seemed to do the trick - now everything is brightly lit...  So my question, is why the transistors? I doesn't seem to need it... 
Secondly, how can I expand this to be 4x4, 8x8, etc.  Is your library scalable - what modifications would need to be made?  I hope you answer, I loved this project...

[gzip]

The transistors allow all levels to appear to be powered at the same time while using a low number of pins. Try using a lower value for the base resistors and make sure you're using a high enough voltage to account for the voltage drop across the transistors.

I tried to keep a scalable library in mind while coding but its still mainly geared towards a 3x3x3. If you're comfortable making modifications I can take a closer look to give you an idea of what it might take. You'll still need either more pins or some type of shift register or driver to power more LEDs.

[fobia]

Hi I just finished my LED cube and I had the same problem with the LED output, it was very dim, after reading your temporary solution in this post, I by pasted the 220 transistors (there was no way I was gonna de-sodldering) and all LEDs work just fine, now my question is what kind of resistors did you used or think we should used for the next project?

[adumas]

Thanks for answering....

My power source is the arduino at 5v - I'm using the Modern Device board. Should I be contemplating an external power supply?

I am changing gears and will use shift registers... I want to build an 8x8x8 cube...  I now have 3x3x3 and 4x4x4 cubes working fine using your library... Which is great.

I think it would be great to have your library handle the 8x8x8.

I just finished making an acrylic template that will allow me to build a more precise cube. The wood base lent itself to errors... I used a laser cutter for the acrylic...