According to Howstuffworks, there are two ARM7 32-bit processors which control the more complicated actions of Pleo. One processes the sensors around the head, while the other controls I/O, image processing and is "where Pleo's personality and behavior exist."

Here we see the SD card slot.

The board uses one of the four 48-pin Toshiba TMP86FH47AUG 8-bit microcontrollers.