RFID ( Radio Frequency Identification ) is the latest small-scale tracking technology that can be used to track and locate objects or people. Pay attention to this new technology and its increasing applications.
Here is a concise description of RFID from Wikipedia —
Radio Frequency Identification (RFID) is an automatic identification method, relying on storing and remotely retrieving data using devices called RFID tags or transponders. An RFID tag is a small object that can be attached to or incorporated into a product, animal, or person. RFID tags contain silicon chips and antennas to enable them to receive and respond to radio-frequency queries from an RFID transceiver. Passive tags require no internal power source, whereas active tags require a power source.