The results I achieved are great, but if I ever do it again, or try a 16x16x16, I would keep the following things in mind...
1) LEDs...
Connections: The legs of the LEDs are actually fairly substantial and there may be a better (thinner) way to connect 3 vertical wires than simply using the existing legs. Consider cutting them off and using stretched wire (as per the "bracing").
Spacing: Not sure if I'd want them much further apart, but using another method of doing the interconnections would allow the LED spacing to be altered.
Transparency: I used clear LEDs and the higher up LEDs ended up refracting light from a lower LEDs (if on), thus looking partially on. Would be interesting to know if diffused LEDs have less of this behaviour. I may try applying some paint to the base of the LEDs to block the light from shining through.
2) Ribbon cable...
I got a multi-colour cable to help simplify the connections, but as the ribbon stays flat, it was never an issue, so using single colour ribbon would also be fine. However, If I did it again, I'd get single core ribbon cable! That would makes it easier to strip (no cut strands), easier to connect (no twisting strands together) and less susceptible to wires breaking (a single strand is stiffer & stronger).
3) Think about the current required...
As each LED should use 20mA to get full brightness, the Latch chips need to supply 20mA per output (which mine did), but the entire chip must be able to supply 8x20mA (160mA), which was possibly a bit beyond the latch chip I used. While I was happy with the result I achieved, if I was to do it again I'd get one where the entire chip could supply > 160mA (ie: try a different model from a different manufacturer) or I'd use twice as many Latches with the inputs & outputs doubled up on each!
6) Think about the wiring effort...
Connecting the wires and the resistors was tedious given the angles and the need to keep them clear. If doing it again, I'd consider doing a PCB that allowed me the fully seat the Latch without bending the pins, fully seat the resistors and connect the wires without needing to be as careful of shorts or breaks! [edit: I've since done the a small PCB to do just that - if anyone is interested, contact me]
7) Precision...
Worth repeating and repeating and repeating again... When you start, make sure your LED Jig is as accurate as you can to get so that the final matrix is nicely aligned, so that you get the best possible result!
Programming reference...
- Micro-controller
- Pattern Design
- LED_Cube.xls [note: it has a macro that colours the cells to make it more usable]
Parts reference...
- 512 x RGB LEDs [+ a few extra in case some are faulty or break]
- Clear 5mm RGB LED from < $250 = contact me
- Possibly better = Diffused 5mm RGB LED < $250 = contact me
- 1 x Micro-Controller
- Digilent ChipKit Uno32 from element14
- Possibly cheaper = Digilent ChipKit Uno32 from Digikey
- 1 x Strip Board
- XXX from element14
- 24 x Latch chips
- 74HC??? from Digikey
- Possibly better = 74HC??? from Digikey
- 2 x Logic chips
- 74HC??? from Digikey
- Possibly better = 74HC??? from Digikey
- 8 x MOSFETs
- XXX from element14
- Possibly better = XXX from Digikey
- ~15m of Ribbon Cable
- XXX from Digikey
- Possibly better = XXX from Digikey
Other minor items to consider...
- Tools
- Soldering iron
- Solder assist
- Solder sucker
- Long nose pliers
- Side cutters
- Extra pair of hands
- Hot melt glue gun
- Consumables
- Solder
- Hot melt glue
- Hookup wire
- Masonite
- Small timber board for the Jig
- Miscellaneous
- 5V DC socket
- Header pins
- Ruler
- Drill & Bit
