Are you low on I/O? No problem! The SX1509 can leverage your I2C interface for 16 extra channels of GPIO. And that's not all! This handy device also contains a fully programmable LED driver and a keypad scanning engine which enables continuous keypad monitoring of up to 64 keys! Since the I/O banks can operate between 1.2V and 3.6V (5.5V tolerant) independent of both the core and each other, this device can also work as a level-shifter. Project description, more information and ordering can be found at https://www.sparkfun.com/products/11502 Datasheet: http://dlnmh9ip6v2uc.cloudfront.net/datasheets/BreakoutBoards/sx1509.pdf Arduino Library: https://github.com/sparkfun/SX1509_IO-Expander/tree/master/Arduino/libraries/SX1509