It’s surprisingly easy to lose not only little things in life, like my keys in the bottom of my purse, but also more often than I’d like, just as easy to entirely lose my car. What if you could “tag” your car with your Android phone or iPhone and follow it back?

With the ToothTag app from NeuAer, currently available for Android phones, you can tag any device to find it and follow it, watching for that device to come into range or to otherwise, disconnect from it. The key feature of the app works by “tagging” a device in range, such as a friend’s phone. Devices are tagged via the Bluetooth MAC address broadcast by every active Bluetooth device. Anytime that Bluetooth device comes into range, you will receive a notification on your phone that the tagged device has come into range. This feature works great if you’re expecting friends to stop by at a bar – or if there are people you’d rather avoid. You can also opt to receive notifications if the tagged device has disconnected, which could work well for parents who want to know where their kids are.

ToothTag also features the option to track events that are API driven by linking with apps such as FourSquare. Using ToothTag, you can set your phone to automatically check in to places you have defined, as well as set parameters about how and when you check in. For those concerned with privacy (such as myself) this is beneficial for redeeming the benefits of geolocation services such as badges and mayorships by allowing you to delay the time of checkins and avoid unwanted disclosure of your whereabouts.

NeuAer was founded by Gnomedex alum Dave Mathews, who also invented the CueCat and holds a number of patents on the tagging of objects. In addition to the core tagging features of Toothtag, other applications have also been built on top of ToothTag to automatically help connect with others close to your location. ToothTag scans local devices for compatible Match.com and LinkedIn connections in range. The app also looks for reviews of nearby Yelp-reviewed businesses and Groupon offers.

Of course, this technology only works if devices you desire to tag are broadcasting Bluetooth. And if you don’t want to be tracked yourself, you can always disable Bluetooth on your devices. In fact, this might be a good reason to consider switching back to a wired headset. Of course, if you frequently lose your car you may want to leave Bluetooth on so you can find it again.