finding your arrows in the rough

[rusty]

These look interesting...

http://www.phidgetsusa.com/cat/viewproduct.asp?category=3000&subcategory=3200&SKU =RFTGAXSM


http://www.phidgetsusa.com/cat/viewproduct.asp?category=3000&subcategory=3100&SKU =1023
From the FAQ
4" range I like your RFID but I need it to read tags up to 1 meter or more? Can you change it? Can I?
Our RFID Reader is a great low cost solution for building interesting projects and prototyping. There is nothing else like it on the market. One of the reasons it is a quick low cost solution is that it is NOT an industrial/retail level RFID reader. It cannot be modified to read further and we have no plans to build a stronger version. To increase the reader to 1 meter or more would boost the cost far beyond what people would be willing to pay due to engineering costs, construction costs, and FCC licensing costs. While we wish we could produce such an RFID reader for our customers it just isn't in the cards.

And another
What's the read range of these chips? Can they be tracked by satellite?
A: There are two types of tags: "passive" (no independent power source) and "active" (containing a battery or attached to one). Depending on a number of factors (antenna size, RF frequency, environmental conditions etc.) a passive tag can have a range of anywhere from 1 inch to 40 feet. Active tags can have a read range of miles or more. Most tags being considered for use in consumer products are passive

[alanesq]

I have posted a question on an RFID forum to see what they think of the idea - I will let you know if I get a reply
I have also emailed a couple of RFID companies to see if I can get a response from them?

Most of the electronics in RFID are to do with transmitting/receiving information where as we just need to detect it is there, so there may be something more basic which can be used ?

[LineCutter]

RFID cresting? 0.5*2" surface area, but wrapped around a shaft with a metal core?

[Mufti]

Would have to be very very light in order not to change the balacne of the arrow if you are thinking of cresting and would have to wrap all around the arrow (i imagine) for detection and balance again.

I would favour internal to the arrow to prevent damage.
I would favour pile of arrow for flight.
I would favour fixed, not shaking around inside the arrow for consistency in flight.
I would doubt it would work from inside the aluminium core of the arrow so we are left with it being outside the arrow - being subjected to all the wear and tear of plunging into the boss


Still, it was fun thinking about it for a while.

[alanesq]

You forget, some of us use wooden arrows ;-)

Some of the rfids are very thin and small and being solid state (i.e. no moving parts) should be able to withstand the pounding an arrow takes?
I have not yet found out if these can have the desired range or if these small devices only have a couple of inch range (if they do have a decent range I suspect the cost of the detector will turn out to be the biggest problem)?

Maybe piles or nocks could be manufactured with them built in (with a plastic section with the RFID encapsulated in it)

[Steppenwolf]

Originally Posted by Steppenwolf

Tried to get onto your web site to check out the proffered score spreadsheet and was stopped - you have a problem.

Everythings o.k. now - thanks

[alanesq]

Still not managed to find much info on rfid tags but it looks like the small tags only have a range of a around 1"
to get a decent range you need a big tag which is no use to us :-(

I still wonder if there is some way of doing this with some kind of tag which re radiates radio waves or a di pole in the arrow (i.e. length of wire) which can be detected by radio ????

This is much more advanced electronics/physics than I am capable of though

[gwynn]

Some of the rfids are very thin and small and being solid state (i.e. no moving parts) should be able to withstand the pounding an arrow takes?

I reckon the technology is out there. Slightly different I know, but I saw an American (God bless 'em) web site that had a nock that lit up when it left the bow, just like a tracer round. It goes out when it stops but if you could keep it energised for a while..........

[Cimbian]

Originally Posted by gwynn

I saw an American (God bless 'em) web site that had a nock that lit up when it left the bow, just like a tracer round. It goes out when it stops but if you could keep it energised for a while..........

I know the guy that holds the patent on these... Seemed like a good idea when he told me about it five or six years ago, but then I didn't know one end of an arrow from the other at that time.

[Rik]

Originally Posted by alanesq

I still wonder if there is some way of doing this with some kind of tag which re radiates radio waves or a di pole in the arrow (i.e. length of wire) which can be detected by radio ????

Would you need a wire? You've got a dirty great ali tube to attach it to (in most shafts)...