Background

RFID or Radio Frequency Identification is a rapidly growing technology in industry. It is frequently used for such tasks as stock management and tracking, personnel access control etc. In its most basic form RFID consists of two elements a read/writer and a tag. The read/writer uses radio frequencies to query a tag which is attached to an object. A large range of different frequencies can be used for RFID, varying from 100s of KHz to several GHz. The choice depends on such factors as the required read range and the type of tag etc.

Examples of tags of different shapes and sizes

There are two broad categories of tags, namely:

a) Passive - the tag has no power supply of its own, but rather derives its power from the signal picked up by its aerial which has been transmitted from the read/writer. This has the advantage that the tags tend to be cheap, and need no maintenance, but they have the disadvantage of generally only having a small read range.

b) Active - the tag has its own power supply. The advantage is more complex functionality and longer read ranges, but tend to be more expensive.

Like barcodes, RFID tags allow for the unique identification of an object, but additionally (depending on the type of tag) they can store data and also in some cases contain small amounts of executable code and even sensors. RFID also has the advantage of not requiring a line of sight to function.

• CNM Knowledge Hunter - An example of a simple mobile game.

• Links to some RFID web sites

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