Few examples of Raspberry Pi controls PCF8574, Remote 8-bit I/O expander for I2C-bus with Python
This example shows how to read and write to PCF8574 I/O expander, and lights up a LED when button is pressed.
Video avaible here: http://youtu.be/Xsl87MCWHjI
This example shows how to rotate lighted up LED to achive wandering light effect. Light speeds up when any button is pressed
Video avaible here: http://youtu.be/TQgOD2pfIVY