Idea: A parking lot compass
Maybe this idea is obvious enough that somebody is already developing it, but I did a quick search and didn’t see anything. So I submit the following.
Why doesn’t someone make a compass to help you find your car in the parking lot? This should be an optional accessory for every GPS-enabled car. You should be able to get a keychain or purse-sized device that will point to your car so you can find it when you come out of the mall, grocery store, etc.
Obviously, this presents a small problem because if someone finds your keys they can find your car and drive away with it. So maybe there’s a keypad on the device so you can type in a password. Or, if it can be done cheaply enough, there can be a thumbprint scanner attached, to make identification even simpler.