Wow, i love this community.
You have surpassed my expectations 1000%.
Thanks heaps for the extensive reply, all the numbers are now starting to make sense (datasheets are more easier to read now)
I made a mistake in the subject, should have been 20 not 30.
I plan on making a proof on concept in the weekend, so for that ill attempt to wire up 8x8 leds and get the software started.
Here is alittle schematic i made up for the proof of concept.
With 8 leds on each row lighting up at one time, that works out to be a 82 ohm resistor on every led/ column.
If im reading your post correctly i need a 560ohm resistor between the base pins (of the row transistors) and their relative bitshifter pin?
Also if i do choose later to try to light all 50 leds) do you have a type of MOSFET in mind? My searching isn't proving so successful.. noone has thought to create a mosfet calculator
If i use the parallel 2n3904 approach, how do you think i should power such an application? I intend on using a cell phone charger wall wart i have lying around for the test, but from it's readings i can (i assume its a max reading) draw up to 450mA from it.
So 450/20 = 22.5 -> so 20 leds.
In which case if i need to light 50 at a time, then i need 10v for 40 (two strings paralleled, running 20 in series).. and thats where my knowledge on power supply breaks down..
Thanks so much for your time.