A Wearable Dehydration Detector

It’s tough for open-water swimmers to cut through waves in a straight line. OnCourse Goggles keep them on track, no surfacing necessary. To set a route, a swimmer sights a way-point and clicks a button to lock it into an electronic compass and shore up the path. Green, yellow and red LEDs in the corner of each eye provide direction. Green in both means on course, red in the right eye means veer left, and vice versa. $200 (est.)