Radio frequency identification devices

Radio Frequency Identification (RFID) is evolving as a major technology with a growing number of uses. Initially it has been used to track goods and assets in retail, manufacturing, hospitals and storage systems, but it has evolved to have many applications outside of these areas. RFID is the technology behind car key-fobs, public transport access (such as the London Transport Oyster card), ski resort lift passes and security badges for access control into buildings.

RFID is a contactless technology that transmits the identity of an object, such as a unique serial number, using radio waves. A typical RFID system is made up of three components: tags, readers and the host computer system.

A RFID tag is a tiny radio device that contains a microchip attached to a small flat aerial. This can be encapsulated in different materials, such as plastic, dependent upon its intended use. A tag can be attached to an object. This object can be read remotely to ascertain its identity, position or state.

The reader, or scanner, sends and receives radio frequency data to and from the tag via antennas. A reader may have multiple antennas that are responsible for sending and receiving radio waves.

The host computer is linked to the reader and can have specialist software designed to process the received data.

When RFID systems are used in conjunction with allied technologies they can remotely sense objects of all types to determine their identity and track their position. They can also be designed to detect other properties.

Because radio waves are used, a RFID tag does not need lineof-sight to operate. The tag can be hidden inside an item or carried on a card or ticket and still be read. A tag can also be fixed to a wall or embedded in a floor. It can then be read automatically as it is passed.

A RFID system can also read many tags together at once. All tags within the range of the reader can be read almost simultaneously as they pass the reader.

There are a range of different radio frequencies in use for RFID tags. An active tag, which incorporates a power source such as a battery, can be read at a far greater range for a given transmitter power. Typically, a passive tag can be read at distances of less than a metre but active tags can have a range in excess of 10 metres.

An important feature of RFID is that data can be written to the tag. The tags can be made with different memory capacities; with extra memory there is the possibility to store extra information. For instance, it could store a list of ingredients. This could be useful for someone with a nut allergy since a simple device could warn them of hazardous products.

Many people, even those with good eyesight, find it difficult to read labels on such things as medicine bottles. With RFID it would be possible for instructions to be transmitted onto a screen so that they can be read using a larger typeface.

Another possibility would be for the washing machine to incorporate a tag reader, and for the tags on clothes to include information about the washing temperature required; then the washing machine could automatically select the correct washing programme.

RFID tags are already used by some blind people to label their possessions (e.g. CDs), and they have a reader with speech output to help them select the correct item. However, there are many more potential applications of benefit to people with disabilities. For instance, active RFID tags could be used to label shops in a shopping centre or exhibits in a museum so that users could obtain audio information about exhibits in a choice of languages.

RFID tags could be embedded in the pavement to give information in audio form to a blind pedestrian. The tags could be part of a painted line, with the blind person using a cane with a transceiver aerial in the tip. The information stored could be the names of shops, bus stops or information about a choice of directions to various destinations.

This illustration shows how a blind person could follow a route that gave them information and options to follow. RFID tags could be embedded in the floor. The reader, in the blind person's cane, would relay audible information.

Go to RFID Guidelines

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