I can't find my bank card and its times like this when I think about a device that should be ubiquitous in this day and age. Could you not get a pack of cheap active RFID tags and use a receiver tuned into the particular frequencies emitted by them to tell you the objects distance from where you are now? Imagine how much easier that would make life. You put a tag on all your essential items such as car keys, wallets, bank cards etc. and write down the frequency for each tag then when you lose something, you tune your receiver into the frequency assigned to the item then track it down. Can you buy a device like this that you can use to track down active RFID tags?