Most people have never seen an accelerometer—a device that measures change in velocity—and wouldn’t know where to look. Yet accelerometers have become essential to modern life, from controlling automobile airbags, to earthquake monitoring, inertial navigation for spaceflight, aircraft, and autonomous vehicles, and keeping the screen image rotated the right way on cell phones and tablets, among other uses. Not surprisingly, demand is rising for inexpensive, high-precision instruments that can be embedded in ever-smaller locations.