Arduino is an open-source electronics prototyping platform based on
flexible, easy-to-use hardware and software. It's intended for artists,
designers, hobbyists, and anyone interested in creating interactive
objects or environments.

Arduino can sense the environment by receiving input from a variety of
sensors and can affect its surroundings by controlling lights, motors,
and other actuators. The microcontroller on the board is programmed
using the Arduino programming language (based on Wiring) and the Arduino
development environment (based on Processing). Arduino projects can be
stand-alone or they can communicate with software on running on a
computer (e.g. Flash, Processing, MaxMSP).

The open-source Arduino environment makes it easy to write code and
upload it to the i/o board. It runs on Windows, Mac OS X, and Linux. The
environment is written in Java and based on Processing, avr-gcc, and
other open source software.