I ran across this 4x4x4 LED cube today:
and reminded me that Christmas is coming; something like this would make a really nice present for one of my nieces or nephews. ( My daughter isn't as impressed with 'blinkenlights' stuff. ). Oh, and for _next_ year, not this one.
This is not the first such "LED cube" I've seen, but it reminded me that all the "cubes" I've seen so far look like they would require a lot of time and patience to construct. Since "time" these days always seems short, and, as best I can recall, I left my "patience" in a checkout line some years back, I started wondering about how one might construct one of these, perhaps even a 5x5x5 or a 6x6x6, _without_ having to bend a lot of wires and then re-wire the LEDs I managed to link up backwards. ( There always seems to be one or two ).
The best approach I could come up with was an adaptation of something I assembled as an SMT LED display a year or so back: a row of header pins cemented to the edge of a small (1.5"x1.5"?) square of transparent acrylic(?) and strips of hand-thinned copper foil tape
1/16" wide ( plus or minus 60% ) running off the pins, with breaks in the strips where I then tack-soldered the LEDs (Mouser 604-APTL3216CGCK - 570nm, 120mcd@20mA). It was ugly, but it worked.There are a few drawbacks to this approach. First, I'd want LEDs with a wider viewing angle (these are only 70deg) or some sort of diffuser. Perhaps a second layer of acrylic-or-whatever with scour-frosted "dimples" laid on top of them?
Second, I'd want to use thinner copper foil, since it's opaque and would obscure the LEDs below it. I'd need to check the current capacity of bare copper, but it might be easier to glue the LEDs down, verify their polarity and fix as needed, then lay a cross-grid of thin copper wires across the LEDs and solder those to the LEDs. It's still a lot of soldering, but it feels like it would be easier to work on a bit at a time than a 3D "wire skelton" arrangement like the ones I've seen for other LED cubes.
Now, there's still probably some sort of "useful" upper limit on such displays -- unless I could find some way to automate the place-and- wire steps -- but even with hand-soldering the 216 LEDs required by a
6x6x6 cube isn't out of the questions as long a I could do a few at a time and then put the assembly away without losing track of what had been done and what was yet to be done.And even with my fumble-fingers skills, soldering (say) 125 SMT LEDs on five separate boards feels like it would be easier to do than building a 5x5x5 cube of supported-by-their-leads LEDs.
The ideal might be 360deg-viewing LEDs on thin, clear acrylic wired with transparent conductors, but I'm not sure if I can achieve that. This year, anyway.
Hm. It might just be simpler to build a POV display "cylinder":
1) Attach two off-the-shelf 8x8 LED panels back-to-back, 2) Mount an edge of that assembly on a motor shaft, and 3) Come up with a _lot_ of teeny slip rings.Then again... 2x6x6 slip rings, assuming row-and-column addressing? Maybe not so simple.
I did find some other efforts along the same lines:
This suggests a way of laying non-transparent copper onto glass:
Oh, and the company that sells this:
is working on an 8x8x8 cube.
Well, this is a GedankenExperiment(*) for now, but perhaps next year? I can always hope.
(*) German for "They cut our research budget again."
Frank McKenney