There are easy ways of getting more I/O pins for any ... output pins of two Arduinos with the same ease as a single Arduino. The hardware setup is fairly simple – just connect A4, A5, power ...

Although there are other ways to do this, [Rod] has decided to write up his method of using two Arduinos and ... IO would be to buy an Arduino Mega with 54 digital IO pins or the Muxshield which ...