PORTLAND, Ore. — Ultra-low power followed by ultra-small size are the two most important aspects of microelectromechanical system (MEMS) sensors used in wearables. MEMS manufacturer mCube Inc. (San Jose, California) discovered this in its research and has set out to meet that not-so-tiny goal. Since mCube already had the industry’s smallest MEMS+CMOS die at 1-by-1 millimeters — allowing room for larger batteries in wearables — they decided to concentrate on technologies that would help extend the battery life of fitness, health monitoring and activity tracking wearables from hours or days, to weeks or months, according to chief executive officer (CEO) of mCube, Ben Lee.