Tiny motion-sensing and data-processing chips from STMicroelectronics have enabled the ultimate activity tracker designed for swimmers by swimmers with positioning accuracy and real-time audio feedback from XMetrics, an innovative wearable-tech maker.   The ergonomic and lightweight device, which shares the company’s name, clips onto the goggles’ band at the back of the swimmer’s head. ST’s 9-axis MEMS inertial module senses the body movements and provides precise data analyzed by the XMetrics...