Everybody know there are several open-source operating systems and application software available. There are several advantages and disadvantages in using open source products. Nowadays if you carefully watch the trend, you will see there are several open source products developed to replace almost all the commercially available software products. Have you ever heard about open source hardware? To the best of my knowledge there are no other projects which became this much successful other than "Arduino".
Arduino is a popular open-source electronics development platform with easy to use hardware and software solution. Arduino hardware is powered by Atmel AVR processor with various input/output capabilities. Software consists of a standard programming language compiler and bootloader that runs on the board. This is developed mainly to help people create interactive objects with minimal electronics knowledge. That is to develop prototypes quickly and efficiently (with the huge amount of support available on the internet). There are significant amount of development going around the world everyday using Ardunio platform. Following image shows one of the Arduino boards called "Arduino Mega 2560".
There are several boards developed by Arduino team and they can be purchased pre-assembled or you can make them yourself (all the hardware design files are available for free). In addition there are several variations made to these boards and sold by third parties.
For you to get the glimpse of the potential of this initiative I have included the TEDGlobal talk given by Massimo Banzi, who says you can create little toys to satellite gear using Arduino platform.
Official Site: http://arduino.cc/