redletterdave writes: "Despite the accelerometer's regular use for games, videos, and other smartphone activities, few people know how the gadget actually works, or how engineers were able to cramp such a small but important piece of technology, which can detect motion in three directions, into a millimeters-thick smartphone. That's where Bill Hammack comes in. Hammack, a.k.a. "The Engineer Guy," is a professor at the Department of Chemical & Biomolecular Engineering at the University of Illinois at Urbana-Champaign, but the 50-year-old college professor also has a second life on YouTube, breaking down how various components of everyday technology work, from digital cameras to fiber optic cables. On Tuesday, Hammack released his newest video, which describes not only how accelerometers work, but also how engineers translate the three-dimensional technology to work inside a tiny chip."