RFID stands for Radio Frequency Identification. It basically encompasses all electronic components that can transmit a unique code to a electronic reader using a particular carrier frequency. A typical RFID system consists of a reader, and antenna and a transponder. In sports timing the transponder stays with the athlete and the reader + antenna combination are stationed at a timing point. There are several frequency bands devoted to RFID and we use several different technologies to capture the time of an athlete as they cross the timing point.
Pictured to the right is a low frequency (134 kHz), transponder used in our HDD and Dual Antenna Systems. The transponder consists of an IC, a copper coil and a capacitor to store energy coupled from a reader antenna. These transponders have no moving parts or batteries and are quite low in cost from a couple of dollars.
We use Texas Instruments (TIRIS) RFID modules and transponders in the HDD system. These components have a proven track record and are used extensively in other sports timing systems around the globe. Many IAAF events use the TIRIS system to time the major marathons and fun-runs of the world. The 134kHz frequency transponders are particularly well suited to sports timing since their read range is very good (up to 1.2 metres above the mats) and the antennas are well focused so that accurate times can be recorded to within 0.1 seconds resolution. The TIRIS components have almost remained unchanged since their introduction in 1994 which demonstrates the longevity of the TIRIS system.
The latest development in RFID technology have certainly focused on UHF technology because of the big reductions in manufacturing cost and improved performance where many tags must be interrogated rapidly in close proximity. Pictured to the left is an Alien Squiggle tag which costs less than 15 cents, can be read from up to 15 metres away and be read together with hundreds more within one second by a single reader. Such performance was unheard of even 5 years ago. The UHF tag uses a tiny chip the size of a grain of sand and an antenna microns thick that makes it ideal for mass production. These tags are truly disposable and therefore it is not surprising that this technology is proving revolutionary for mass participation event timing.
The past 5 years have seen big improvements in reader and tag sensitivity as well as novel designs to counter the effect of metal and water on performance. Research has clearly demonstrated that by using a simple 3mm foam spacer on the tag, read performance is boosted dramatically when the tag is placed on the back of the runners bib. This technology is now readily available using our Ultra disposable tag system.