If you could see your swing and know what you did wrong, you’d improve it on the next hole, wouldn’t you? Golfsense allows you to do just that, calculating a 3D view of your swing so you can play it back on your smartphone.
How it works: The little gadget attaches to the back of your glove (at .6 ounces, you’ll hardly notice), and its sensors track and analyze the club’s speed and position, as well as your swing’s tempo and path. At the same time, your iOS or Android device—when kept in your pocket—will read your hip rotation, too. Then, once the data is all on your phone, you can zoom in and out, rotating the image to see your swing from any angle. ($130; golfsense.me)