I guess my question is really simple. With a chip and a matt you can be pretty certain tht a "read" will occur near the actual finish line. With a directional attenna you hope to aim it to only pick up along your finish line. With omnidirectional (is that what you mean by circular?) antennas you have a blob of a pick-up pattern, really not a finish line at all. The RFID timing system manufacturers have tried many clever ways to combat this from placement and pickup patterns, to complicated signal algorythms they've put into their sofware. I just wanted to know how you will account for this?
Looks like the answer is, it's too early to tell?
I'm asking about accuracy, and I believe your answer above is about reliability. I have no doubt about the reliability of RFID. The largest retailer in the world (WalMart) pioneered RFID in their inventory control system. It's very reliable. But it would have difficulty determining whether a box of fruitloops is about to enter the warehouse, at the warehouse door, or has just crossed the threshold. That level of accuracy is irrelevant to them, but I think useful for a road race.
The antenna's project radio waves outward and form a cone shape exiting the antenna - the further away you go from the antenna the wider the read zone is. For example I can walk up behind an antenna with a UHF tag in my hand it it doesn't pick it up until I'm right on top of the antenna.
Circular just means that the UHF tag can be places horizontal or vertical on a surface - proving a more reliable system since the bib's will be bouncing all over the place coming though the finish line. The optional TR200 registration reader that can be used with my software is "Linear" - which means when I turn an inlay on it's side (so that it's vertical) the reader has trouble reading it.
Having the antenna's facing each other directly on the finish line instead of projecting out towards the runners should provide similar accuracy to the low frequency antenna's used in mats. Take a look at the "Orbiter" system shown here and you'll see how I anticipate mine working: http://www.youtube.com/watch?v=t8A33...layer_embedded
Of course the Orbiter system is like all other RFID timing systems currently on the market - VERY expensive!
I'll keep you posted as I do my testing. And again, I'll post videos and I even have a few people that are going to remote into my computer and watch me test it live.
I was just looking through some other posts in this forum and I found something that gave me an idea. You could also place the inlays on inexpensive disposable wristbands like these: http://www.tabband.com/TabBand-Stat-p/tabbandstat.htm
This would probably increase the reliability a lot, and you can use different colored wristbands to denote "Walker" or "Runner". Plus, runners would probably enjoy having something they can wear around as a conversation piece the rest of the day.
I get it. Makes a lot more sense than pointing the antennas down range.
Originally Posted by Brian_Agee
<$0.15 a band. That would great. Looking forward to see how your R&D goes!
Thanks! I'll keep everyone posted.
Also, if anyone thinks of anything they wanted added or improved simply let me know and I'll add it if it's a good idea.
I've used the orbiter system. Read rate in a critical situation was less than 90% with a $35 microwave tag.
Facing antennas at each other, with two cone shaped read areas, will still not create and accurate "line" for a finish line as csandy asks. The advantage of floor mounted mats that point the cone shaped antenna up is:
1. the cone shape and read height can be standardized VERTICALLY so it is reading all runners in roughly the same place.
2. All antennas are aligned similarly.
3. since all antennas are aligned in the same direction, you can get a much more precise "line".
For the above reasons (and a number of others) it will be good for races up to 500 people, but I wouldn't consider it "professional" level development.
Good luck, I do hope it works out, and just ask that you're honest with those you market/sell it too (unlike what Jaguar does).
I need to put you on my RFID mailing list, I haven't been posting on Runners World or on this website very often. If you'd like to be on this list PM me your email address. I'll post a quick update on here now.
My recommended setup has changed after further testing. You're right, the read rate is not as good as I would like with the antennas facing each other, and the inlays stuck on the bibs. So now I'm recommending shoe tags - you can buy dry inlays or wet inlays for $0.10 - $0.25 depending on the quantity you buy. It's easy to turn them into shoe tags that hang down on the side of the runners shoe when placed on a single lace before the shoe is tied. If you bought "wet" inlays (meaning they have are adhesive on the back) you can sacrifice a few bibs (or some other flexible waterproof material - even paper-thin plastic) and cut them so that the inlay has a 1/2 tab sticking out of the top (if you stood them up longways). You fold that 1/2 tab in half and cut a V notch in it to create the hole that the shoe lace is fed into.
As for Antennas: I'm recommending that the antennas be lining one side of the finish line, with the first directly on the finish line (this first one catches the tag nearly every time - if not every time in my testing), all other antennas are positioned about 3ft apart on the same side of the finish line - going into the finish line area. This provides multiple backup read zones, eliminates the need for running cords across the finish line (meaning no mats needed), and since the antennas are about 1ft off the ground the hardware required to mount the antennas is minimal (< $20 per mount)- and easy to set up and tear down. Again just for extra reliability I'm recommending that each athletes be given two shoe tags (each tag is programmed in my software to return the same bib number), if the antennas were on the right side of the finish line shoot (from the finishers perspective) they would have a shoe tag on the outside of their right shoe and on the inside of their left shoe. Two shoe tags would still be about 50% the cost of 1 Jaguar tag.
You may wonder "What if people don't put them on right or don't wear them at all". You'd have this same worry if people forgot to wear their bib or put their bib on the outside of the jacket and then took their jacket off during the race. Since it's such a critical component I plan on having volunteers helping them put them on.
I also found that the the small Thinkify TR200 can also attach to one of my large finish line antennas (each antenna cost $88 with cable). I tested it for over an hour sprinting by the single antenna attached to it. I had a shoe tag on each foot programmed to return different bib numbers. If I cross within 7ft in front of the antenna it read both tags 100% of the time, outside of 7ft it would sometimes only read one of the tags, but it never missed both tags. So I'm actually going to have 5 antenna on my finish line, if the FX7400 goes down I've got another chip timing system (the TR200) still processing tags. So pretty much I'll have two chip timing systems, with multiple read points, and multiple tags - all for WELL under what Jaguar cost in every angle you can look at. My goal with this system is absolutely no missed tags, I just want to sit back and watch as my camera takes a picture of every finisher automatically, and every now and then I'll reach over and hit the F11 button to print current results.
I have been posting videos of the testing and development of this project here:
Since this is a holiday weekend, I plan on creating and posting a lot more videos with this new setup.
Looks like development is going well. Can you post finish line pictures? My thinking is that because your chip triggers the camera, you'll be able to tell what kind of "read zone" you're getting by looking at where an array of pictures are taken in relation to the actual finish line.
Sure, I'll post the photos that were taken when I created the "Test TR200" videos I posted on YouTube: http://www.youtube.com/user/BrianAgee127
Originally Posted by csandy
In these videos the camera was set to Full Auto with Automatic Zooming and everything, so there was a slight delay on the camera end for each photo. On race day I have everything set to all Manaul settings so that the photo is captured immediately since the camera doesn't have to do any 'thinking' before it takes a picture.
You can see these photos here: http://ageeracetiming.com/events/9/photos.aspx
With the shoe tags I get reads the very second my foot hits the finish line, no sooner, no later. This weekend I'll try to post some videos where you can both the computer screen and the finish line so that you can see exactly where the finishing time is recorded each time. Thanks for the question, I'm happy to answer anyone's questions or put the system through any kind of test people would like to see.