Matt Buys matt at MATIES.SUN.AC.ZA
Tue May 17 08:48:00 CDT 1994


 CSIR (South Africa) is the developer of the concept and is focusing on
 transferring their knowledge to applications providers.

 Just imagine if one could accurately "read" the entire contents of a
 herbarium shelf in less than a second without the need for unpacking;
 stock-taking could be a simple act of passing a scanner over the
 cupboards to document the entire contents within minutes....

 This, and much more, is no longer in the realm of science fiction.  The CSIR
 has developed a specialised, fully patented electronic tagging system with
 the vision of incorporating a minuscule radio transponder in the printed
 packaging of just about any item at very low cost.

 What makes the CSIR system totally unique, is that it includes protocols to
 allow for many tags to respond to "interrogation" by a reader at the same
 time.  Hitherto the ensuing multiple response signals interfere with one
 another confusing the signal.  To avoid the problem radio tagged items have
 had to be moved one at a time past a reader.  This is often impractical and
 sometimes impossible.

 The CSIR system, which is protected by patents and is being licensed
 internationally, allows tags to be read at the same time from readers with
 different polarisations to allow for "unfriendly" orientations of the tag
 antennas.  The protocols applied allow many items of the same type, with the
 same case or product number, e.g. a number of packets of soap powder, to be
 counted without the need for serial numbers.

 The tag comprises a single silicon chip that, for example, can be attached
 to a herbarium label or specimen, and is invisible to the user except for
 the benefits derived from it.  The tags are called passive because they do
 not need their own batteries.  Instead they extract energy from the radio
 frequency (RF) field used by the interrogating reader to "illuminate" the
 items to be identified.  The tags can be read from up to four metres away.
 The properties of radio allow the radio waves to penetrate paper and so read
 tags that are not visible.

 Key problems that prevented the implementation of such an approach in the
 past include the lack of simple, low-cost designs specifically targeted at
 this problem; the large physical size of currently available transponders;
 the non-uniform distribution of RF fields from the interrogator;
 interference caused by many tags all responding to the interrogator at the
 same time, thereby jamming the reader in the interrogator; the impossibility
 of electronic counting of many tags with exactly the same type number
 without depending on a system of serial numbers; the physical attachment of
 transponders to items; and a limited responding range for passive tags.

 The CSIR has solved most of these problems with its new system, and simulated
 field tests have proved the system to be highly accurate.

 While tagging of goods in supermarkets is the long term aim the new system
 has numerous other possible applications, especially owing to its capability
 of handling responses from many tags with different orientations.  Early
 applications could include checking the contents of a truck by simply opening
 the rear door, taking an inventory of a warehouse by means of a portable
 scanner, or examining a book case or pile of documents with a hand scanner to
 identify the presence of a sought article.  Other possible uses are in
 sorting luggage at airports; sorting parcels; asset control, people tracking,
 mail routing and animal tagging, and last but not least, for curatorial

* Matt Buys                    *                               *
* Dept. of Botany              * Tel: (021) 808 3604           *
* University of Stellenbosch   * Fax: (021) 808 4336           *
* Private Bag X5018            *                               *
* 7599  Stellenbosch           * E-Mail: matt at *
* South Africa                 *                               *

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