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1  Using Arduino / LEDs and Multiplexing / Re: 4x4x4 RGB Cube schematic on: January 10, 2014, 10:19:33 am
hey sorry for bringing this post back :-P quick question..   i order the wrong type of LED's (common cathode) .. and i soldered as specified in this instructable  ... how hard and what can i do to convert this from a common anode to a common cathode cube???  any help would be greatly appreciated .. even if anybody can just point me in the right direction.. thanks!

If you want to use the TLC5940, you will need to use common anode LEDs. If you want to use common cathode LEDs, then you will probably want to either use shift registers and a whole lot of resistors, or charlieplex the LEDs. Another option is transistors. I have a cube that uses 20 npn transistors, and 20 resistors, and 64 common cathode RGB LEDs.

I have an unfinished website linked below with the details.

2  Using Arduino / LEDs and Multiplexing / Re: Programming pic with arduino for charlieplex cube on: April 24, 2013, 11:07:04 am
You can do this with any arduino that has 16 or more tri-state I/O pins (uno, nano, mega, ...).
3  Using Arduino / LEDs and Multiplexing / Re: Charliecube problem on: April 15, 2013, 12:07:01 pm
Youre welcome. Let me know if you do anything interesting with it.
4  Using Arduino / LEDs and Multiplexing / Re: Charliecube problem on: April 14, 2013, 10:23:36 am
I've modified the original cubeplex.h file. It now includes 4 maps for the 4 ways that are easy to miswire the cube. Assuming you aligned all the spires, and the only problem is that you didnt have the cube in correct orientation when wiring the circuitry to the cube. You still have a 25% chance of getting it right, but if you didnt, Scroll to Flush Buffer, and comment out and uncomment different sections of code, till your cube works right.

When checking the cube to see if it looks right, use just the shift-squares program (comment out like mentioned in the previous post), if the cube looks ok, then comment shift-squares out, and uncomment fountain. If it looks weird, you are probably off by 2 sides and should try the map for 2 sides off. Then try fountain and see if it looks right. (it starts in the bottom center, goes to the top, then down the outside.) When it looks right, you have it set right.
5  Using Arduino / LEDs and Multiplexing / Re: Charliecube problem on: April 13, 2013, 09:32:17 pm
In the cubeplex.h, change your code to this:
Under :
/******************************** FLUSH BUFFER ********************************\
You will find this mapping table that looks something like this:
  //TODO the pins values need to be changed so that the mapping.h file can
  // change them using #defines
  if (_cube_buffer[ 0] != 0)flushElement(copy_frame, 4, 8,_cube_buffer[ 0]);
  if (_cube_buffer[ 1] != 0)flushElement(copy_frame,16, 4,_cube_buffer[ 1]);
  if (_cube_buffer[ 2] != 0)flushElement(copy_frame,12,16,_cube_buffer[ 2]);
  if (_cube_buffer[ 3] != 0)flushElement(copy_frame, 8,12,_cube_buffer[ 3]);
  if (_cube_buffer[ 4] != 0)flushElement(copy_frame, 4, 7,_cube_buffer[ 4]);
  if (_cube_buffer[ 5] != 0)flushElement(copy_frame,13, 4,_cube_buffer[ 5]);
  if (_cube_buffer[ 6] != 0)flushElement(copy_frame,11,13,_cube_buffer[ 6]);
  if (_cube_buffer[ 7] != 0)flushElement(copy_frame, 7,11,_cube_buffer[ 7]);
  if (_cube_buffer[ 8] != 0)flushElement(copy_frame, 4, 6,_cube_buffer[ 8]);
  if (_cube_buffer[ 9] != 0)flushElement(copy_frame,15, 4,_cube_buffer[ 9]);
Note: above is just a little bit of the table, the whole thing is 192 lines, and wont fit in one message.

I attached a copy of just the table in a text file. Copy the contents, and paste it in place of the original table.

It will either change it the right direction, or the wrong direction, and the wrong direction might not be obvious right away.

If you go into charlieCube.ino  you can comment out the programs you dont want to run. for now, comment out all but shiftsquares.

void loop() {
//  planarSpin();
//  fountian();
//  trifade();
//  tunnel();
//  chaseTheDot();
//  planarFlop3D();

Then upload it and see if the squares move around correctly. If it looks good, go back and uncomment out those lines charlieCube.ino.
6  Using Arduino / LEDs and Multiplexing / Re: Charliecube problem on: April 13, 2013, 05:37:28 pm
Looking over the wiring, I can see that changing the mapping wont do what you want.

I did try a few different mappings, and got changes, but not the way I wanted.

Changing the z value seem like a better way to modify it, but im not sure where or how.

There is something called FLUSH BUFFER, and it looks like a mapping for each LED. That might be a good place to make some changes.
7  Using Arduino / LEDs and Multiplexing / Re: What's a "bright enough" LED for this project? on: April 13, 2013, 11:27:16 am
14 digital + 6 analog = 20
He mentioned using 20 RGB LEDs, which means he probably needs 60 outputs (20 R, 20 G, 20 B = 60), assuming they want to control each LEDs color independently.
8  Using Arduino / LEDs and Multiplexing / Re: Charliecube problem on: April 13, 2013, 11:18:12 am
The height being off is due to the connections between the arduino, and cube being 90 degrees off. I have a few charliecubes, and I've done a lot of documentation and testing.

I looked at the map file, but I never modified it. It seems to me that there are 4 possible ways to connect to the cube, and 4 different maps would solve the problem of having the cube turned the wrong way when wiring it to the arduino.

There is also another ay to solve the problem, but its even more difficult (rotate each spire 90 degrees.)

I dont know the ports or how any of that works, but it looks like the beginning of the file has 16 groups of 3 lines like this:

#define P1B 0x00
#define P1C 0x00
#define P1D 0x04

My guess is that changing these will do what you want, but I havnt done it, and I havnt messed with any ports stuff.

Heres my charliecube documentation:
9  Using Arduino / LEDs and Multiplexing / Re: Driver recommendation on: April 11, 2013, 10:50:29 am
If you want to power Four 3.3v 350mA LEDs, you will need about 1.4 amps (350 x 4 = 1,400) at 3.3v, or you could run them in series at 13.4v at 350mA. Either way should work, but parallel is probably the better way to do.

I dont know any of those products listed, so I cant really advise you on that.

There are many different arduinos out there, some can handle quite a bit of power (like the mega), but Im pretty sure that none will do 1.4A. They do have 3.3v and 5v power sources, but not enough current to run those LEDs directly.
10  Using Arduino / LEDs and Multiplexing / Re: Driver recommendation on: April 10, 2013, 12:59:46 pm
That will be too much current for any arduino, you will need an external power supply.

You will also probably want some transistors, and resistors. Assuming you want to turn them all on and off at the same time, and not individually, you could use one big transistor, and one big current limiting transistor (and probably another  couple resistors on the transistor.)

If you try to hook even one of those up to your arduino, and run it at full current, it will most likely damage or break it.
11  Using Arduino / LEDs and Multiplexing / Re: 4 x 4 x 4 LED Cube with Shift Registers on: April 09, 2013, 10:08:34 am
I couldnt download the schematic to see how that cube is built, but from the description, it sounds like how most cubes are made in planar fashion, but each plane is split in half (8 groups of 8 LEDs).

Its not as hard to build as you might think. My transistor cube breaks up plane into 4 lines, if you did the same thing, only connected 2 lines together on each side, you have the same thing as he is describing (2 lines of 4 LEDs is 1/2 plane).

In the picture below you can see 16 LEDs that are made up of 4 lines of 4 LEDs. 4 of these make one 4x4x4 cube. Im using RGB LEDs, but you could do the same thing with single color LEDs.

If you connect 2 of these lines together, you make 1/2 plane. You could connect them horizontally, or vertically, either way should work.
12  Using Arduino / LEDs and Multiplexing / Re: RGB SMT LED Cube, resistors, drivers, and shift registers. on: April 08, 2013, 04:56:59 pm
Thanks for your help, its a big improvement. Im sorry for any hassle.
13  Using Arduino / LEDs and Multiplexing / Re: RGB SMT LED Cube, resistors, drivers, and shift registers. on: April 08, 2013, 03:31:59 pm
Thanks for removing those offensive posts.

I am curious about the claims of vitriol though, but whatever, its probably not important.
I dont really see any value in the posts after I posted my calculations. Those are mostly just a bunch of incorrect assumptions and of little or no educational value.
14  Using Arduino / LEDs and Multiplexing / Re: RGB Lamp based on Monitor dominant color on: April 08, 2013, 11:44:39 am

This is a similar project, you can probably glean enough info from this to build your own. This one does many points around the monitor, but you could simplify it to one.
15  Using Arduino / LEDs and Multiplexing / Re: 4 x 4 x 4 LED Cube with Shift Registers on: April 08, 2013, 10:48:53 am
Thats prettymuch how I did mine. After I converted mine to use shift registers (it was originally directly connected, and only used one resistor per plane. It was very few parts, but it used all the io pins.

Converting it to shift registers mean that I went from lighting 1 led at a time, to lighting 16 LEDs at a time. which means you really need to add 4 transistors (one for each plane) to handle the current from 16 LEDs.

I think that the original program that I used was modified from a 3x3x3 code to 4x4x4 before I got it. When i upgraded the cube to use shift registers, I modified that program to use stuff from shift out.

Ive since modified that program to work on my new cube (transistor cube), but its still a bit buggy.

I've attached the program, you are welcome to do whatever you like with it. I think this version is setup for common cathode, you may need to modify a few things for it to work with your cube.
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