Am I right in thinking that for each plane you have a sepreate cathode connection and that all the cathodes are not connected together on each plane? Otherwise it would never work would it.Have you done any tests to see how these LEDs look when they are on, if you need diffusers or what current you need to run them at.Once you know the current for each LED you can then work out how much current to sink with the cathode sinks, you might need a FET here.You then can look into how to provide that current at the anodes.
but all the cathodes per plane are connected (thats 48 cathodes tied together per plane as the LEDs have 6 leads)
my lack of parts is making it hard
I've been reading about MAX7219/7221 chips, they are common cathode drivers, Is there a good reason why I shouldnt try to find some of those?
Quotebut all the cathodes per plane are connected (thats 48 cathodes tied together per plane as the LEDs have 6 leads)You mean anodes here don't you. It is the cathodes that are negative that are connected together.The LEDs are capable of 60mA so you intend to run them at 20mA, is that right.Do you know when you start multiplexing them they will look dimmer because they will only be on for one quarter of the time. One way round that is to boost the current.If you are using resistors then there is no point in running the shift registers at a reduced voltage, you just alter the value of the resistor.So given a 5V feed what values do you come up with for a 20mA current?Quotemy lack of parts is making it hardResistors are less than a penny each unless you pay vastly inflated prices. QuoteI've been reading about MAX7219/7221 chips, they are common cathode drivers, Is there a good reason why I shouldnt try to find some of those?The reason is that you cannot control the brightness of each individual LEDs. Also they will not work with the way you have wired it up.
Resistors around here are about 25 cents each,
It could be my dividers are not working right,
I will need 100ohm for red, and 150 for blue and green.
the forward voltage on the red is 2.15
and really really dim when all the LEDs on a plane are lit.
I couldnt even buy shift registers locally,
My old cube uses 4 resistors, one for each plane,
QuoteMy old cube uses 4 resistors, one for each plane,Well that explains it, very poor design that.