I've been reading different threads about shift registers, and drivers etc... but I'm still having a hard time understanding what the best options are for different ways to increase IO pin for my scenario... Any advice?
I have a Uno with Ethernet Shield (so as I understand I can't use Digital 10,11,12,13 for normal I.O and also 4?, is this correct? )
My set up is,
Digital 0 - Unused (so far)
Digital 1 - Unused (so far)
Digital 2 - Input_Pullup for a N.O switch
Digital 3 - Input_PUllup for a N.O switch
Digital 4 - Unused
Digital 5 - Input_Pullup for a N.O switch
Digital 6 - Output 5v to a relay
Digital 7 - Output 5v to a relay
Digital 8 - Output 5v to a relay
Digital 9 - Unused (so far)
So I have 3 pins left to use as I understand. 0,1,9.
I would like to add a couple 7 segment LED's, and in the future 1 or 2 more Input_Pullup for switches and 1 or 2 more output to relays.
Ah ok, I didn't realize that I could use the Analog pins as digital as well. Thank you.
I am only using 2 of the analog pins at the moment, so that frees up some pins for me.... I will also have a look at your sketch that your referenced, and will look at the board you sent from Crossroads... are they easy to use and code ?
Alternative way is using an input/output port expander IC like MCP23008 or MCP23017 via I2C protocol. You will lost 2 pins for I2C connection but can get many more I/O pins.