I'm looking to build a large LED matrix (approximately 10 X 70) and wanted some ideas on what hardware would be the easiest and cheapest.
Description of project: i'm looking to make a stock ticker from scratch. i'd like it to be 5 pixels high (bi-color: Red and Green) and about 70 wide to scroll stock market information.
i think the easiest configuration is to treat this as two matrices each 5 x 70, one on top of the other. hence the 10 x 70 quoted above.
i don't have bi-color LEDs, i'll instead be using about 350 red and 350 green LEDs in a grid as pictured here: http://cooolest.50megs.com/LEDmatrixgrid.jpg (black lines are just grid lines)
so on to the hardware:
my first thought was to use about five 16-bit constant current source drivers daisy chained. do these parts even exist? i've seen constant current sinks with shift registers that can be chained together, does this exist for current sources? 5 of them would get me 80 columns, and i could connect the rows straight to the arduino (is it easier to use an IC for this?) my only concern is dissipation of that much electricity. there could be as many as 80 LEDs on at a time, is that a problem?
my second idea was to use a setup similar to the Lightuino with two 8 channel, or one 16 channel LED driver for the rows and a couple M5451 chips to provide 70 constant current sinks for the columns. anyone have good suggestions for power driver chips?
is one approach better than the other? is there an easier way to do this?
any advice/suggestions would be great