Shift Registers

People often complain about the number of i/o pins available on the arduino microcontroller. There is a very simple solution for this that anybody readily using microcontrollers has probably considered: a parallel to serial shift register. This is probably one of the most useful tutorials I’ve seen started by Carlyn Maw and NYC Resistor’s own Tom Igoe on how to use them. This page is an excellent resource. shift register tutorial

Yes, I know what you are thinking: “that’s so obvious, its right on the arduino website.” I know right? Well good, then I won’t have tell you where to look the next time you are wondering how to read data from 8 switches while only using 3 pins on the arduino. This leaves you 10 i/o pins on your board.