Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software.
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 running on a computer (e.g. Flash, Processing, MaxMSP).
The hardware reference designs (CAD files) are available under an open-source license, you are free to adapt them to your needs.