Last month, Apple began prepping app developers and accessory makers on how to take advantage of the new Bluetooth 4.0 Smart technology in the iPhone 4S. Previously, Bluetooth was a fairly locked-down affair on the iPhone, with only officially supported Bluetooth profiles (like tethering and hands-free) available. Find My Car Smarter, an app for finding your vehicle in a crowded parking lot, was one of the first in the App Store to utilize the newly opened functionality of Bluetooth 4.0, so we decided to put it through its paces.

Find My Car Smarter is currently wrapping up a Kickstarter campaign, so you'll need to donate if you want to give it a shot. In exchange for an $25 donation, you'll receive a tiny USB Bluetooth tag and a download of the 99-cent app — with that plus an iPhone 4S, you'll have the necessary gear to retrieve your lost car. You'll also need a USB port in your car; if you have an older vehicle (like the 2002 Subaru WRX we used in testing), a USB charger that plugs into your cigarette lighter does the trick. To set everything up, just plug in the smart tag, turn on your car and fire up the app — it'll prompt you to pair the smart tag with your iPhone, at which point you're ready to go. In our testing, setup and paring worked flawlessly.

The app itself is very basic: aside from a spartan settings menu that lets you choose between metric and US distance measurements and an option to disable background processes, you're looking at the standard Google-powered map with a familiar blue dot marking your location. However, once you turn your car off, the Bluetooth connection with your iPhone is severed and the app drops a pin on the map with the last location your iPhone's GPS was able to track you at. When you have to venture out of the mall back to your vehicle, the app shows where you parked with that pin and tells you how far away the car is — if you're on the wrong side of the parking lot, it'll be obvious pretty quickly. When you turn the car back on, the iPhone and Bluetooth tag re-pair, so it can keep track of the location next time the connection is cut.

We tested this system out on a busy afternoon shopping around the Boston area, and it worked as advertised, with a few caveats. The system failed to to pair properly once, so the map showed our car a good 900 meters away from where it was actually parked. Also, due to the heavy reliance on Bluetooth and Location Services, you'll want to keep an eye on your battery life, though the drain didn't feel particularly heavy in our tests. Plus, once you're away from your car, you can turn those settings off to save battery if you're going to be away for a while.

Speaking of location services, it's worth noting that it appears that this app keeps the running constantly. We reached out to the developer, who confirmed that they do indeed stay on, but that the active GPS isn't always running. Apparently, the app uses a service called "Monitor Significant Location Change" — with it, the app uses cell tower location to note major changes in your location. Since it uses cell location, it doesn't drain any additional battery; this service also allows the app to resume working if its killed by iOS memory management. Still, if you're uptight about managing the services your phone uses, that persistent arrow in your menu bar might start to grate on your nerves.

Despite these few quirks, the app works well, though it's hard to say worth the price of entry unless you really have a hard time remembering where you park. As an example of what Bluetooth 4.0 Smart technology can do, however, it was more encouraging. Now that Apple has opened up the Bluetooth gates for the iPhone 4S, we're hoping to see more innovative marriages of apps and accessories.