Arduino is an open-source hardware plat form based on easy-to-use hardware and software. You can tell your board what to do by sending a set of instructions to the microcontroller on the board. Arduino is an open-source platform used for building hardware related projects. Arduino consists of both a physical programmable circuit board often referred to as a microcontroller and a piece of software, or IDE Integrated Development Environment that runs on your computer, used to write and upload computer code to the physical board. Arduino Uno is one of the more popular boards in the Arduino family and a great choice for beginners.