The Port Expander Shield allows you to easily add more digital outputs to your Arduino. In version 0.4 there are 24 digital outputs all controlled via I2C so it only uses 2 pins of your Arduino.
- 24 digital input/outputs
- Address pins are pinned out
- Up to 3 shields may be used for a total of 64 digital pins
Information including Schematics/Usage can be found here
You can also find additional posts about this shield here: posts tagged with port expander shield