RFID (Radio Frequency Identification) uses electromagnetic fields to automatically identify and track tags attached to objects. Tags contain electronically stored information. Passive tags collect energy from the radio signals of an adjacent RFID reader. Active tags have a local power source (for example, a battery) and can work hundreds of meters from a reader. Unlike a barcode, the tag should not be within the scope of the device, so it can be embedded in the monitored object. RFID is one of the methods of automatic identification and data collection.
Application
RFID tags are used in many industries. For example, an RFID reader attached to a vehicle during production can be used to track progress on a conveyor line. Labeled pharmaceuticals can be tracked through warehouses. Implantation of RFID microchips into livestock allows the identification of animals.
Because RFID tags can be attached to money, clothing, and property, or implanted in animals and people, the ability to read personal information without the consent of the user poses a serious privacy problem. These risks have led to the development of standard specifications regarding personal data security. Tags can also be used in stores to speed up checkout and prevent theft.
History
In 1945, Leon Theremin invented a tapping device for the Soviet Union, which retransmitted radio waves with added audio information. Sound vibrations during vibration affected the diaphragm, which slightly changed the shape of the resonator, which modulated the reflected radio frequency. Despite the fact that this device was a hidden device for listening, and not an identification tag, it is considered the predecessor of a USB RFID reader, as it was activated by audio waves from an external source. Transponders are still used by most operating aircraft. Earlier, similar technology, such as an RFID tag reader, was regularly used by the Allies and Germany in World War II to identify aircraft.
Mario Cardullo's device, patented on January 23, 1973, was the first true predecessor of modern RFID, as it was a passive memory radio. The original device was passive, powered by a polling signal. It was demonstrated in 1971 by the New York administration and other potential users and consisted of a transponder with 16-bit memory for use as a paid device. Cardullo's core patent covers the use of radio frequencies, sound, and light as transmission media.
Area of use
The initial business plan, presented to investors in 1969, demonstrated the following areas of application for the RFID reader:
- use in transport (identification of automobile vehicles, automatic payment system, electronic license plate, electronic manifest, vehicle routing, monitoring vehicle performance);
- banking (electronic checkbook, electronic credit card);
- security ( personnel identification , automatic gates, surveillance); medical industry (identification, patient history).
An early demonstration of the reflected power (modulated backscatter) of RFID tags, both passive and semi-passive, was done by Stephen Depp, Alfred Coelle and Robert Freiman at the Los Alamos National Laboratory in 1973. The portable system ran at 915 MHz and used 12-bit tags. This method is used by most modern UHFID and microwave RFID readers. In modern life, such devices are very in demand.
Specification
The RFID system uses tags affixed to identifiable objects. When making a DIY RFID reader, it should be borne in mind that two-way radio transmitters, called interrogators or readers, send a signal to a tag and read its response. RFID tags can be passive, active or passive. The active tag has a built-in battery and periodically transmits its ID signal. The passive battery (BAP) has a small battery on board and is activated with an RFID reader. Passive tag is cheaper and less because it does not have a battery. Instead, the tag uses the radio wave transmitted by the reader. However, for the passive tag to work, it must be illuminated with a power level about a thousand times stronger than for signal transmission. This affects interference and radiation.