Hi. Starting up my 1st Arduino project with the Mega. Planning to make a dart scoreboard and looking for advice as to what LED driver option I should take.
The project will have 6pcs of 3x7seg displays and 42 additional LEDs. This totals 168 LEDs. Also for context there will be 9 push button switches and one 4 throw switch.
I have a pretty good idea how to build it but im not so sure the best and easiest way to interface with all these LEDs. Ive seen a few different options and would appreciate if anyone with experience here has some feedback. Keep in mind I'd like to keep cost down and would also like this to run on the Duemilanove besides the Mega I have now. [1.] Use shift registers as described here: Link1. It seems like using shift registers rather than a serial protocol like SPI or I2C would require much more programming, right? Also i guess I'd need to use 21pcs of 595 chip. that would also get a bit pricey with so many IC's. [2.] There's the MAX7219 (Link2), an SPI interface chip that supports 8pcs 7seg displays. I'd need 3 of these but they are pricey (~$10ea). Also im not sure, can i use 3 of them on the serial bus? how easy is it to progam these using SPI? [3.]I really like the SAA1064 (Link3). It controls 4pcs 7seg displays, is affordable (~$1.5ea), and uses I2C which seems pretty easy to program. Unfortunately I'd need to use 6pcs of these but apparently you can only address up to 4pc on the I2C bus (so says the datasheet). Anyone know of a way to get a couple more on there?
So Im not sure what the best route to go is for all these LEDs. Are there viable choices other than the ones above? perhaps a combination? Is it possible to do I2C and SPI? Any help is much appreciated.