So just what exactly is Arduino? At first sight, Arduino is a small microcontroller board with a USB port that comes in several models. There are even ‘daisy’-shaped boards (Lilypads) intended for wearable applications, i.e. to be incorporated into garments. The Arduino board is programmed in a language very similar to C using Open Source tools available for Windows, Mac, and Linux. The hardware is also Open and anyone can make their own Arduino – the circuit diagrams and PCB photo masks are available free over the Internet.