Arduino is an open-source electronics platform, based on easy-to-use hardware and software. Arduino boards are able to read inputs: light on a sensor, a finger on a button, or a Twitter message. And turn it into an output: activating a motor, turning on an LED, publishing something online. Thanks to its simple and accessible user experience, Arduino has been used in thousands of different projects and applications. The Arduino software is easy-to-use for beginners, yet flexible enough for advanced users. Arduino is open-source hardware. Therefore, many cheap, Arduino compatible microcontrollers exist. The hardware reference designs are distributed under a Creative Commons Attribution Share-Alike 2.5 license and are available on the Arduino website.
The name Arduino comes from a bar in Ivrea, Italy, where some of the founders of the project used to meet. The bar was named after Arduin of Ivrea, who was the margrave of the March of Ivrea and King of Italy from 1002 to 1014.