The Duemilanove Arduino was a microcontroller board released in 2009. Like all other Arduino boards, the Duemilanove had open source hardware, meaning that it could legally be produced by any manufacturer without paying any licensing fees. The board was then paired with similarly licensed software to ensure compatibility with computer software and other microcontrollers. Arduino is a microcontroller platform designed to allow professionals and hobbyists to rapidly create electronic device prototypes.
As the main entry level board, the Duemilanove Arduino was quite popular. It used a USB interface to connect to computers and could handle a variety of sensors and controllers. Additionally, the Duemilanove Arduino sported 32 kilobytes of on-board storage, twice the capacity of the Diecimila, which it replaced. Like its predecessor, the Duemilanove could be extended through the use of shield boards, which added additional functionality such as wireless communications, GPS devices, or specialized connections like Musical Instrument Device Interface (MIDI).
This board is more limited than advanced models and its successors, but developers have used it to create some very interesting projects. One of the most common uses for the Duemilanove was robotics. Even without a specialized shield, it could easily control motors and sensors could allow a robot to perform simple tasks like following a light.
By early 2011, the Duemilanove Arduino had largely been replaced by the Uno Arduino. The Uno has many of the same features as the Duemilanove, but adds a considerably faster processor and an upgraded USB interface. Another significant change is increased uniformity in manufacturing; the Duemilanove Arduino had several swappable components, where a faster or slower component could be used. The Uno eliminated this variability, in order to make the board easier to create programs that would be guaranteed to execute at the same speed on any Uno board.
Even though it is now officially retired, many older Arduino building plans still mention the Duemilanove Arduino. In most cases, these plans can be easily adapted to work with the Uno instead. The only times when the Uno would not easily replace the Duemilanove are times when a programmer used the limitations of the processor in the Duemilanove to control execution speed. In those cases, software must be artificially slowed in order to run properly on the new platform. The open source nature of the Arduino platform also means that, despite being officially replaced by the Uno, the board may be available from manufacturers who choose to continue to produce the cheaper Dueminanove board.