The problem, I tend to bite off more than I can chew and I know very little about electronics, programming or pcb design
• individually is certainly not a option! • is multiplexing the way to go?
• are there other options available?
• Is it possible to light all 15^3 at once?
I have commenced research on multiplexing and the concepts behind it and how it works and why it is used
* What components are required to make that happen?
* What are the power requirements of such a cube and how would I meet them?
Does the ability to light up all LEDs simultaneously require multiple multiplexes (such as 7 x 83), which would physically operate separately, but visually as one?
I am really going to need help/advice to realise this project. I hope a few of you take pity on this fool and help him on his way.
Then I would really suggest you build something else first. How about a 3 x 3 x 3 cube, that way you will get a little acquainted with LED's, soldering/building, IC's that might be handy for multiplexing and programming the thing (even if a 15^3 is another beast than a 3^3).
Also, you would only need 27 LED's (or 30, a couple of extras is nice to have), and don't have to buy 3500-ish as the first thing you do. A mere 1% of cost and work for a test run. Even if including an Arduino, I think - 3500 LEDs isn't cheap?
One important thing, if you really go through with this I would suggest choosing diffused LEDs, not LEDs with clear lenses. Reason being the diffused ones are more visible from a broader viewing angle. I couldn't find any reference to whether or not the ones you found are diffuse or not. Would be a bummer buying all those LEDs and having to sandpaper 3375 LEDs by hand....
Btw, have you seen this 16^3 cube? Really awesome! But I don't know whats powering it (page wouldn't load atm):http://www.youtube.com/watch?v=Aj3_v7xCyJ0
Also I don't know how feasible a 15^3 cube is with an arduino.. maybe one of the bigger ones, like the Mega, or a Sanguino. Or use two or more arduinos maybe. Just some loose suggestions.
Also you'd need to decide if you want PWM ("grayscales") and/or RGB But given the size I think not!
Power requirements for just the cube will depend on what multiplexing scheme you choose.Lets say you manage to lit an entire layer (15x15) at once, then this is the power requirement (+ logic circuitry and the microcontroller etc). This multiplexing would then light each layer in the cube for 1/15th of a frame time. Since each LED is also lit like that, you could overdrive them somewhat to get it brighter.Lets say one LED use 20 mA as standard, but you drive them with 50mA (this is for 1/15th of a time - btw I choose this as an arbitrary example). Then one layer (and also the hole cube sans logic circuitry) would require 225LEDs * 50mA = 11.25 Amperes, at whatever voltage you use for the LEDs.Not necessarily, but maybe in your case because of the size. If you do, take care that they are syncronized and have the same frequency, or else you might see flicker. Shouldn't be a problem if you control it all from the same microcontroller.Btw with multiplexing not all of the LEDs light up simultaneously, but if done fast enought, the eyes wont notice (POV again).
There are some really nice and talented people here, which usually answer specific questions, but nobody will write the program for you (for free, anyway. Unless you are really lucky But whats the fun in that?)
o what you are saying is that as only some of the LEDs will be lit only some of the time, the power supply does not necessarily need to possess the ability to power all LEDs.
I will listen to your advice and make a 3^3 cube as a warm up.
If I was to continue down the path of a 15^3 cube and 1 cycle consisted of 1000 milli seconds, the number of LEDs to be lit in one second would be 1000 (i.e. one LED for each milli second in a cycle), is that correct? If that is true, is it possible to manipulate the timing in a cycle, for example 2000 milli seconds?
The problem, I tend to bite off more than I can chew and I know very little about electronics, programming or pcb design.
whether I need common cathode or common anode LEDs, or if in fact it matters at all
What Constant Current Sink Output actually means
whether I need something (not sure what) between the Arduino and the TLC5947's to supply power to the LEDs
whether I need something (not sure what) between the TLC5947's and the LEDs to power the LEDs
My advice:-If you are having to ask such fundamental questions you are not yet up for tackling such a large project. Do some smaller stuff first.