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Topic: RFID Timing system (Read 2021 times) previous topic - next topic

Hello Everyone

I am busy designing a timing system for mountain biking and track cycling. I have already got an MS Access database which does the timing and calculating of results.

I would like to automate the data entry because currently someone needs to sit and type numbers in manually.

The obvious solution would be an RFID antenna which sends the rider identification (RFID) through to the timing system.

The only antenna I've found which might be able to do what I need is the Poynting A-PATCH-0025 (http://www.poyntingcommercial.com/DirectoryListing/DisplayCommercial.aspx?name=169#prodlist=3).

It has a 2.3m range, so I should be able to mount it on a pole on the side of the mountain bike finish line and maybe mount two above the track finish line looking down.

Am I on the right track and would I be able to interface this with an Arduino UNO? The datasheet says it has a RG 58 cable with N(f) connector...

Thanks in advance.

Sheldon

PaulS

Have you gotten a quote from them? How much is that device?

Grumpy_Mike

As well at the antenna you will need an RFID reader that works at that frequency, that is 
860 - 960 MHz. This is not the normal RFID frequency used in many hobby projects and it is likely to cost you a lot of money.

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The datasheet says it has a RG 58 cable with N(f) connector...

That is like the sort of connector you get from your satellite dish. It needs plugging into your RFID reader and the output of the RFID reader needs to be connected to the arduino. Only when you know what reader you are using will you be anle to see what is needed at the arduino end.

Hi Paul, I can get it for about $80.

Hi Mike, thanks for the info, that's exactly what I was wondering and what I was looking for. So the problem is the frequency (I figure this, but wanted confirmation). I have found a Skyetek UHF reader (M10), but it costs $470! That's taking my project way out of budget!

Anyone know if it's possible to build a 125 khz antenna that will pick up at about a 2m range? Tag collision should not be a major issue...

Thanks

Sheldon

Grumpy_Mike

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but it costs $470! That's taking my project way out of budget!

I am rather surprised it is that cheap actually.

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if it's possible to build a 125 khz antenna that will pick up at about a 2m range

Well I used to work in RFID and I don't think you can get a passive RFID reader to that range. It takes about 250mS to read a tag so I don't know how fast they are going but that might put more of a stretch on the required range.

Before I was employed there I believe an engineer once made a 1 meter RFID reader for a show but it was a big coil and very heavily tweaked. And in the show it didn't work because the sales men mounted it against a metal pillar. You would also have an effect from the bike. I could imagine if you made a coil that they could drive through you might just get something but it would require you to break the law as to the permitted radiated power. And as I say it would be speculation as to if it could be made.

250mS should be doable. At 20km/h which is faster than I expect the riders to come through would give 1.4m.

The bike would definitely affect it, I know the professional timing systems used at the races are affected by the bike. The people from the timing companies alway wonder around and blast the riders when they've connected the tags directly to their carbon forks!

Building a coil the riders would have to ride through would work, but I'm not keen on breaking the law just to make my life a little simpler...

I wonder if the race organiser (my Dad) would have a problem with riders stopping at the finish line to swipe a card against a reader?? That might solve all my problems!

Otherwise I might need to put this off for a while until the hobby electronics have expanded a bit more...

Another option, but one which I think is far more complicated would be to use a webcam to take photos as the riders cross the line, then to use some sort of image processing to identify the riders from their number boards.

Simplest solution at this stage is to have the riders stop and swipe a card...hmmm

Grumpy_Mike

What about a laser bar code scanner?

I don't understand how a bar code scanner would be better than a RFID reader where riders swipe a tag as they come past. Would you mind explaining Mike?

Thanks!

Mike, sorry to be picking your brain like this. Would what I want to do be possible at 13.56Mhz? I've found a relatively cheap reader at that frequency!

Grumpy_Mike

The problem with RFID is the range, given sutiable optice the range should not be an issue with lasers.

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Would what I want to do be possible at 13.56Mhz

Possibly easier than 125KHz but still difficult.

Okay, thanks a million Mike! I'm now going to try sleep with this overactive brain! Tomorrow my research into lazer bar code scanner begins!

Once again, thanks for your help!

Sacman

A little late to this topic but I go with a friend who races hare scrambles (motocross style woods racing) to take pictures. They use an RFID system for timing and scoring. Each rider has a rather large 'tag' that they ziptie to their handle bars and as they pass the start/finish line they are scored and timed. I have never paid much attention to them but this might help steer you in the right direction.

Luck,

Wade

Grumpy_Mike

I suspect that these are active tags, they contain a battery and a transmitter which is why they are so large.

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