As a follow-up question to your answer concerning the impracticality of utilizing an RFID-enabled smartphone to locate a golf ball (see Could a Smartphone Track a Miniature RFID Tag Placed on a Golf Ball?), is the technology suitable for locating an item that is, say, 50 feet away?
Near Field Communication (NFC) readers currently used in smartphones are designed for short-range reading only. Even if you were to place an ultrahigh-frequency (UHF) reader in a smartphone, there would not be enough energy available to locate a tag from that distance, because the phone manufacturers limit the amount of power available to peripherals in order to prevent a peripheral from draining the battery. Even if those restrictions were lifted, you would still not be able to read a passive tag from that range.
It might be possible to create a proprietary phone add-on that could interrogate an active (battery-powered) tag. That way, the tag would broadcast a signal and the phone reader would be able to pick it up. But that would also raise tag cost to around the $50-per-tag range, which would make it useless for most consumer applications.
—Mark Roberti, Founder and Editor, RFID Journal
Previous Post Where Can I Find a Fixed HF Reader for Use Outdoors? »