RFID = Radio Frequency IDentification. An ADC (Automated Data Collection) technology that: – uses radio-frequency waves to transfer data between a reader and a movable item to identify, categorize, track.. – Is fast and does not require physical sight or contact between reader/scanner and the tagged item. – Attempts to provide unique identification and backend integration that allows for wide range of applications
Mario W. Cardullo claims to have received the first U.S. patent for an active RFID tag with rewritable memory on January 23, 1973. That same year, Charles Walton, a California entrepreneur, received a patent for a passive transponder used to unlock a door without a key. A card with an embedded transponder communicated a signal to a reader near the door
A transponder is a wireless communications, monitoring, or control device that picks up and automatically responds to an incoming signal. Transponders can be either passive or active. A passive transponder allows a computer or robot to identify an object. Magnetic labels, such as those on credit cards and store items, are common examples. Simple active transponders are employed in location, identification, and navigation systems for commercial and private aircraft.
A Radio-Frequency IDentification system has three pArts: A scanning antenna A transceiver with a decoder to interpret the data A transponder - the RFID tag - that has been programmed with information. RFID tag may be of one of two types: Active RFID tags Passive RFID tags
STEP 1 IC or microprocessor Transceiver RFID Tag Reader Tag antenna antenna
STEP 2 Transceiver RFID Tag Reader Tag antenna antenna
No on-board power source (for example, a battery) Uses the power emitted from the reader to energize itself and transmit its stored data to the reader. Reader always communicates first, followed by the tag.
ACTIVE RFID TAGS Has on-board power source (for example, a battery; other sources of power, such as solar, are also possible). Own on-board power supply to transmit its data to a reader. No need for readers emitted power for data transmission.
Read-only tags Tag ID is assigned at the factory during manufacturing Can never be changed No additional data can be assigned to the tag Write once, read many (WORM) tags Data written once, e.g., during packing or manufacturing Tag is locked once data is written Similar to a compact disc or DVD Read/Write Tag data can be changed over time Part or all of the data section can be locked
Reader functions: Remotely power tags Establish a bidirectional data link Inventory tags, filter results Communicate with networked server(s) Can read 100-300 tags per second Readers (interrogators) can be at a fixed point such as Entrance/exit Point of sale Readers can also be mobile/hand-held.
RFID tags do not require line-of-sight. They can be read through cardboard, plastic, wood and even the human body. RFID tags are less susceptible to damage. An RFID tag is securely placed within an object or embedded in plastic, enabling the system to be used in a variety of harsh environments, such as areas of high temperature or moisture. RFID Eliminates human errors, reduces labor and provides quick access to a wealth of information. The data of a read-write (RW) RFID tag can be rewritten a large number of times.
Add an RFID tag to all items in the grocery. As the cart leaves the store, it passes through an RFID transceiver. The cart is rung up in seconds.
No line of sight required for reading Multiple items can be read with a single scan Each tag can carry a lot of data (read/write) Individual items identified and not just the category Passive tags have a virtually unlimited lifetime Active tags can be read from great distances Can be combined with barcode technology
RFID systems are typically more expensive than alternatives such as barcode systems. Tag collision and reader collision are common problems with RFID. Tag collision occurs when numerous tags are present in a confined area. RFID technology gives rise to numerous security concerns. Since the system is not limited to line-of-sight, external (and malicious) high-intensity directional antennas could be used to scan sensitive tags.