If you are heading down to Burning Man this year make sure you wander over to the More Carrot theme camp at 5:30 and Baghdad to have a look at this Illuminatrix which is a one metre square LED matrix.
“The system is contructed of 16 custom built PCBs, each containing a PIC16F1827 microcontroller which receives data via I2C from a master board and controls 3 MAX6964 LED Drivers via I2C – one each for red, green and blue components. Each board then runs two ribbon cables of 8 RGB LEDs.
The master board is running on a PIC18F26J50, a very powerful little PIC with an awful lot of I/O capability. Its reading the animations from an SD Card formatted with FAT32 using an SPI interface, it then chunks this data up, and sends it via the main I2C bus to the slave boards.”