Input/Output Expansion With An Arduino - Let's Make It - Episode 31 - -

So what do you do if the inputs and outputs on your Arduino are not enough for you and you need to add more.  In this episode we talk about just one of the ways.  We introduce you to a 16 bit I/O chip that runs over i2C.  You can put up to 8 of these chips on the i@c bus to add 112 I/O ports to your Arduino using just 2 pins on the Arduino itself.

The chip we demonstrate is a Microchip MCP23017.  You can get that chip from our online store at