Collecting data about everything we do has become an obsession for iPhone owners. This golf swing analyser is a great example of when it works well.
The GolfSense 3D Golf Swing Analyzer is a plastic pebble that straps to your golf glove and collects speed and direction information about your swing, which it then sends to your iOS device. It weighs just 17g, so having it on your glove really won't slow you down at all (though we did find it a pain to fit securely).
The sensor connects to your iPhone through Bluetooth, sending the data it collects over to it immediately, which you can then browse on the accompanying app (the app beeps when it captures a swing successfully). The information it grabs is enough to produce nicely comprehensive results.
Initially, it uses the speed and direction data to show you a 3D representation of your swing, which you can rotate and zoom in on, and is particularly useful for comparing how well you matched your backswing and downswing (and is also good for seeing how skimming the ground of other mis-hits skewed your arc).
Tap the "Analysis" section at the top and you get a series of screens, each giving information about different areas of your swing, from club head speed to hand speed, wrist rotation and hip rotation (the latter of which is detected using your iPhone itself, if it's in your pocket), and from backswing posture to predicted distance (which didn't seem too accurate to us). Some of these just give you the information, while others will actually tell you if you're doing well or not.
For the most part, you don't need to interact much with the app when playing - before your swing, just hold your club still with the head next to the ball for one second and the app will prime itself - but you do need to manually identify which club you're going to use before each swing. When you interact with it (at the end of the round or after every swing) is up to you; either's fine as far as the app goes, and if you'd rather review everything on the larger iPad screen, all your data syncs to it over the cloud.
While out on the course, we found ourselves only reaching for it after a particularly good shot, checking whether it was a fluke or whether we'd nailed the technique. As with most of these types of things, the issue with using the GolfSense system properly is that there's only so much you can do with it on its own - you really need to combine it with some coaching.
We're not criticising the Swing Analyzer for that, mind, but it's important to remember that an analysis of what you're doing with your club is only half the story - you need someone to tell you what to do with your body, too.
The biggest disadvantage of the GolfSense sensor is that it really eats your battery life - you'll need a battery pack for your iPhone when doing a round of 18.
It isn't cheap, but it produces a wealth of useful information from a tiny package. Not a perfect hole in one, then, but if you're serious about improving your swing, it definitely makes the cut.