UHF Timing System

How many times have you run a race and given any thought to all the effort that must go into timing your race (and everyone else’s)?

According to today’s patent, the previous systems required a time-consuming association process – i.e., associating each bib number with an identification (ID) number of a radio frequency identification (RFID) in the bib or chip.

For example, the patent states that previous chips were read-only memory (ROM) based RFID tags or chips which operate in the LF or low frequency (e.g., <135 kHz) or HF or high frequency (e.g., 13.56 MHz) bands.  Each ROM chip would have an associated identifier (e.g., a serial number).  The ROM chips would have be arranged on a wire or line in order to maintain their sequence.  And one at a time, each identifier would be then associated with a bib  number for the event.  Of course, the bib  numbers would also have be later associated with the identity of the participant too.  All this information would be kept in a spreadsheet or lookup table or other suitable database, and all the chips would have to be kept in the proper order.  Problems might arise when a human error was made in this association process; after which considerable efforts must then be made (e.g., by event organizers and managers) to reprocess the tags and bib numbers – essentially repeating the entire association process.

Generally, RFID tags operate by a reader (e.g., at the start and finish lines) emitting radio frequency (RF) energy in a region proximate to the chip or the bib (having a chip).  This energy is absorbed by the chip or tag and provided the amount of energy is sufficient, a current is induced in a coil in the tag which in turn activates an integrated circuit (IC) which transmits the tag’s identification back to the reader (e.g., at the start and finish lines).

US Patent 8,179,233 teaches that Class 1 Gen 2 tags require ultra high frequencies (UHF) and include writable memory into which data can be wirelessly encoded (rather than ROM memory).  Writable memory eliminates the more lengthy process of association – instead, the bib number can be written directly into the tag as its unique identifier.

The UHF range is approximately 900 MHz – 928 MHz.  The patent states that in the past, UHF was thought to be unreliable in applications such a race bib numbers, because too much radio frequency (RF) energy would be absorbed by the human body.  However, according to the patent, the inventor discovered that any absorption losses could be minimized by separating the tag from the human body by at least one inch or providing proper shielding.  The inventor further went on to prove that UHF was feasible using empirical data.

The inventor studied and tested various configurations of antennas and tags and conducted pilot testing in actual races – pilot locations included the Chicago and Detroit Marathons of 2007 where the primary timing chip was the ChampionChip and his chip was the pilot chip.

Today’s patent (U.S. Pat. 8,179,233) was issued on May 15, 2012. The full text may be found here (last visited May 23, 2012).  The patent appears to be owned by the inventor Arash Kia of Portland, OR.

I write this blog without taking a position as to the usefulness, desirability, novelty, aesthetics, functionality, etc. of the products or processes discussed in my posts.  Naturally, readers are free to take any position they prefer and comment accordingly, provided it is in good taste.  However, if I am silent with respect to your comment, such silence should not be construed as any agreement or disagreement to the comment; I hope you can appreciate that I simply prefer to remain neutral in such matters and merely report Patent Office and triathlon-related news.  Thanks!  🙂

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