View Full Version : Reading a pet's implanted RFID?

08-11-2006, 08:19 AM
From another post in this fourm, I gather that the RFID reader sold by Parallax won't work... so does anybody know of a good place to get one that will read those tags?


08-11-2006, 12:35 PM
well first of all you need to find out what frequency they are running on, once you do that you find a reader within that frequency to find it

08-12-2006, 12:50 AM
My googling indicates that they vary; but all are low-frequency. I'm particullarly interested in the HomeAgain chip; as that's the one that my local vet uses; and it's a 125khz chip, and I think it's an FDX-A.

From http://www.homeagainid.com/news/prs.cfm?action=article&prid=3:
" HomeAgain uses 125 kHz Full Duplex (FDX) microchips "

Other sources of info:


So... anybody have any ideas?


Chris Savage
08-12-2006, 11:19 AM
There are hermetically sealed RFID tags available for our reader. They are at the following website (manufacturer of our tags). I hope this helps. Take care.


Chris Savage
Parallax Tech Support
csavage@parallax.com (mailto:csavage@parallax.com)

08-12-2006, 03:03 PM

That site is a little hard to navigate... where do you actually BUY the product and can you buy just one? i was thinking about getting one of the sealed plastic ones for my dog on her collar and i wanted a keychain one for my newest project im working on.... hammerhead the reader is 125 KHZ so i dunno why it wouldnt work?

Beau Schwabe
08-12-2006, 03:19 PM

There are other factors than frequency that you must consider. A blanket statement such as your first reply to this thread is not necessarily correct.

Consider for a moment IR TV remotes..... MANY of those operate at the same frequency (38kHz) BUT you will be hard pressed trying to get a SONY remote
to turn on a MAGNAVOX television. The reason is that not only does the frequency need to match, but also the way that the signal is modulated. <--- And there
are a billion ways to do that.

The reason that the 'CYNTAG' sensors will work, is because they speak the same language as the Parallax RFID reader (i.e. the signals are modulated the same)

Beau Schwabe (mailto:bschwabe@parallax.com)

IC Layout Engineer
Parallax, Inc.

John R.
08-13-2006, 12:10 AM
I think this may have gotten a bit off track.

I believe the initial poster is trying to read the tag already embedded in his pet, not necessarly trying to find a capsule for his pet that the Parallax reader can read.

Keep in mind that if you're after tagging your pet, there is more to it than just putting a capsule into the pet. The tag needs to be read by "someone" (e.g. animal control, a vet, humane society, etc.) and then has to have a way of correlating the data from the tag to data about the animal.

The systems used all involve having the tags embedded, and then havin the animal registered with a "central" database. "Central" being a less than ideal situation at present.

Without getting into the legal and political issues too deeply, there are some issues with what "standard" to use, law suits, counter law suits, etc. Each company has its own point of view, and like the TV remotes, uses different methods and standard (or non-standard) ways of encoding and reading the data. They also do not share a "central" database, but each have thier own.

It's been a little while since I was really digging into this, so some of the issues may (or may not) have been resolved.

In direct answer to hammerhead's original post, your best bet is to start with the company that manufactures your tag, in this case "Home Again" and go from there. If you can confirm that the FDX-A standard is used, that "might" open the door to other vendors. The 'Might" factor coming into play if any kind of "encryption" were used on the data.

Trying to google for "RFID" readers may get you frustrated. Most of the "RFID" vendors are targeting "commercial" applications, and getting data is hard enough, products in low quantities can be challenging.

In this applicaiton, try googling the end application, RFID Pet TAGS, and variations on that. You'll find some vendor information, and also find references to all the fun stuff I was talking about earlier. There are also a number of blogs you'll run into, and some of them talk about "self readers".

Good luck!

John R.

8 + 8 = 10

08-13-2006, 02:46 AM
Have you tried to read the tag? Even if the data is encrypted you should get something. (he says, not having a tagged animal to test it on)

- Stephen

John R.
08-13-2006, 04:12 AM
I don't think the "tag type" will be able to be read by the Parallax reader. That reader is set up for "EM4100" series tags, and I don't think that any of the pet tagging is being done with those tags. There is an FDX-A and FDX-B, as well as other "protocols" or standards. I believe what would happen is that the Parallax reader may trigger the tag, but any return would be discarded by the reader as bad data, "noise" or just plain ignored.

John R.

8 + 8 = 10

08-13-2006, 04:20 AM
I haven't gotten Maria tagged yet (I just got her from the feline rescue folks); but intend to do so when I take her up to the vet for her first "well-cat" visit. I would like to only have one tag in her (both for interference reasons and for not-turning-her-into-a-feline-pincushion reasons http://forums.parallax.com/images/smilies/freaked.gif ), and consequently would like a reader that would read one of the recovery tags that have a broad support infrastructure at shelters and vets. The HomeAgain tag is supposed to not be encrypted; but the AVID tag is... which is one of the factors influencing my (current) prefrence of the HomeAgain tag.

Supposidly, both HomeAgain and AVID now have "universal" readers that read each other's tags... how widespread these are in the field, I don't know.

I don't have a Parallax reader, nor (as mentioned above) do I have a tag in Maria yet, so I haven't been able to just try it yet (but, as the Parallax reader works with HDX chips, and I am under the impression - based on several citations on several websites, including HomeAgain's official site - that the pet chips are FDX-A; I think I'm not going to be able to use the Parallax reader. Bummer, dude... http://forums.parallax.com/images/smilies/sad.gif )

So, what I was hoping for is somebody who could say "Sure, I've got an XYZ reader, and every time Fluffy walks by the workbench, it goes off!!!" But, short of that; even somebody who could say "Check out XYZ's website, you can order a module there that should work" would be helpfull...

>> And there are a billion ways to do that
Beau; you underestimate the cleverness of those rascally RFID engineers! I'm sure that they could figure out MORE than a billion ways! http://forums.parallax.com/images/smilies/smilewinkgrin.gif http://forums.parallax.com/images/smilies/freaked.gif http://forums.parallax.com/images/smilies/smilewinkgrin.gif


08-13-2006, 09:40 AM
OK -- I now have in my hot little paws an "Allflex P/N 860007-001 Sterile Injector Needle with FDX-A (FECAVA) Transponder" that apparently came with my adoption fees (along with an enrollment into the 24PetWatch tracking service). When it comes to finding a reader, I'm still striking out with google though... I might have to breakdown and build one even (I wonder if an SX is up to the task?)

So....anybody have any of these? ---->>> http://forums.parallax.com/images/smilies/idea.gif

Or any good book recomendations should I have to go the DIY route?