A library along with an arduino sketch to use an Arduino board as a port expander.
Usage : Everything is pretty much the same as using pinMode/digitalWrite/digitalRead functions in standard arduino.You just add an ST before that. For example: you are initiating the library this way
#define ADDRESS 0x08 Ardu_expander ard_IO(ADDRESS);
Then when you want to set pinMode: ardIO.STpinMode(10,OUTPUT);
same goes for analogRead etc. Currently many functions are unavailable such as interrupts etc which would be added as soon as possible