Arduino is the 'family name' for a wide range of simple, affordable, single board computers, many featuring the ATmega328 8-bit AVR microchip. Introduced in 2005, the boards are one of the best ways for beginners to get to grips with programming simple code and building custom hardware devices.
Most of the boards are programmed via the free 'Arduino IDE' which runs on PC, Macs and Linux computers.
Need to expand the capabilities of your Arduino? With most boards you can fit on additional boards called 'shields'.