What is AVR?
AVR is a line of microcontrollers produced by a company called Atmel. A microcontroller is a tiny self-contained computer in a chip, usually about the size of a stick of gum, a coin, or smaller. It contains all the elements needed to run a stripped-down computer system: a microprocessor (the number-crunching unit), memory (where running programs temporarily store information), flash storage (where programs themselves are stored), and peripherals that in some way affect the outside world.