One time, I spent hours wandering the parking lot after a concert. I really wish I had marked the location of my car and not relied on my memory to navigate. Next time I find myself in that situation, I'm going to use Find My Car Smarter. It's a Kickstarter project from FMC Smart which automatically marks your location every time you park your car.
The system uses a low-power Bluetooth Smart device (shown below), an iOS app and a Bluetooth 4.0 compatible phone like the iPhone 4S. The Bluetooth Smart device is a small USB dongle that fits in a standard car charger. It plugs into your car's 12V accessory charging port and stays there. The iOS app, Find My Car Smarter, connects to the Bluetooth Smart device and runs in the background. The app stays connected to the dongle until you power down the device by turning off your car. If your car doesn't power down the accessory port, then the app will disconnect when you walk away and get outside the dongle's 10-foot range.
It's this disconnection that triggers the app to mark your location. This all happens in the background automatically. You don't have to open the app or remove the Bluetooth device. You just stop your car and walk away knowing that your location has been pinned. If you're away on vacation and don't need your car, you can turn off these background processes. This stops the app from automatically saving your car's location, so you'll have to remember to turn it back on when you get home.
When you're ready to return home, just fire up the app, and it'll show both your current location and your car's location on a map. The app calculates how far away you are from your car, and how long its been parked in that place. It'll even use your phone's compass to help you walk in the right direction.
I tested out the system for a few weeks, and I highly recommend it to anyone who regularly parks in a large parking lot. It's so convenient. You only have to set it up once and then you can forget about it. In practice, I found it to be accurate within 10-20 feet. The app brought me close enough to my car that I could easily find it with a quick scan.
The system is easy to use, accurate and reasonably priced. I also like the fact that it uses cutting edge technology like Bluetooth Smart. The only drawback I found was the size of the Bluetooth Smart dongle. It's so small that it's very easy to lose. If you keep stored in a USB car charger, you'll do ok, but if you carry it around loose in your bag, there's a good chance you will lose it.
The Find My Car Smarter system is available as a Kickstarter project. It's reached its funding goal, and the first round of devices shipped this week. When the Kickstarter part of the project ends next week, the devices will be available for purchase from the company's website. The basic package includes a Bluetooth Smart dongle and the iOS app for US$25. For an extra $5, you can add in a USB car charger if you don't already have one.