Perhaps you have seen the Arduino at a local retailer, heard about it from a friend who purchased one, or just saw a cool project on the Internet that piqued your interest. What is the Arduino? Most simply, it is an affordable, small-scale, simple computer that focuses on interaction with the outside world (Figure 1-1).
Most of the computers you are familiar with are controlled almost exclusively through the keyboard and mouse, touchscreen, or trackpad. An Arduino allows you to take information from the outside world with sensors that measure temperature, light and sound levels, or even the vibrations underneath your feet, and convert these measurements into motion, sound, light, and more.