Arduino gets piggyback from Raspberry Pi
The AlaMode board makes it possible to build a bridge between the Raspberry Pi mini-computer and the Arduino prototyping platform and the many shields available for it. Although the Arduino-compatible board connects to the Pi's GPIO header, the two boards operate independently, sharing data via the GPIO connectors. The AlaMode board is able to connect standard Arduino shields.
This makes it easy to record information such as sensor data from an Arduino and process it on the Raspberry Pi in the programming language of a user's choice. If required, the AlaMode board can also be programmed from the Raspberry Pi. The board is priced at $44.95, but distributor SeeedStudio has currently sold out.