Arduino and Raspberry Pi are both highly developed and large systems. Thanks to the ARPI600 card, these two platforms are gathered under a single roof. This card is used with Arduino Shields and hardware / software resources Raspberry.
The card is connected to the Raspberry Pie + / B + / 2/3 models via GPIO pins and you can start using thousands of Arduino Shields with Raspberry without the need for extra connections. You can also get Raspberry-XBee connection practically thanks to the XBee socket on the card.