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
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
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.
Knowledge Hunter - An
example of a simple mobile game.
to some RFID web sites