RFID Tag Specs?

jtrz

Hi all,

I want to start using the RFID reader for something.· But I don't want to use the tags available from Parallax for anything other than testing.· No offense.· But they're not suitable for my purposes.

I have a Zebra label printer/encoder available to me so I can create my own tags and they would be the same tags that you see on objects in pharmacies, etc.

My question is...If I'm going to print my own tags, what are the label specs I should be looking for in RFID tags?·

Is there a reference I can look at for these specs?

Has anyone done this and are there any pitfalls to watch out for?

Thanks,

John

Franklin

I'm pretty sure the frequency is 25khz but I don't know the coding. Try googling the forum as this has been addressed before.

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- Stephen

Mike Green

Current RFID tags are much more than just a printed tuned circuit. They include a chip that rectifies the 125KHz (or other frequency) carrier to produce power used to transmit a specific binary code (and checksum) back to the RFID reader. Do a web search for "wiki rfid" to find an excellent summary article on RFID.

Kyle L.

Zebra manufactures RFID label printers in both HF and UHF frequencies. So, the specs of the tags would depend on the model you have access to.

Something else to be aware are the different tag standards. There are a lot - you need to check which standards are supported by the printer, then check which standards are supported by the RFID reader-unit. If you are using HF tags, then the standard would probably be the basic ISO15693 (many companies manufacture tags that meet this standard). For UHF, there are a slew of different popular standards; so you would have to check the printer and the reader to be certain.

As far as I know, Zebra manufactures its own labels especially for their printers, but only in UHF (SmartTags, I think their called).

I don't have experience with RFID label printers, so I can't recommend specific tags or whatnot. But, basically, all tags that follow a specific standard are pretty much identical. But, you can really only buy tags that are made from reputable companies, so I don't think of quality as an issue.

Also, RFID tags tend not to do well around metal or water, so you need to be careful about what you're tagging. In addition, the tags need to be oriented parallel to the reader in order to get a good read - which means you have to make certain that the tags are oriented properly on the tagged objects.

As for what Parallax offers - I believe the reader module utilizes the 125 Khz frequency. So, it doesn't support writing data to tags and the reader must be fairly close to the tag to get a read (unless you buy/make a powered external antenna).

There are a number of 13.56 Mhz tag reader/writer units available that interface serially with a computer (or via TTL to a BASIC Stamp). I don't have experience with UHF, so I can't really say much about that, other than the antenna design on UHF tags is something else to look into, if that is what you'd be using.

Obviously there is tons of literature available on the Internet - just do a Google search. There is the RFID Journal (www.rfidjournal.com/) with a lot of resources, and there are many books too. The expensive books are mainly textbooks - something like "RFID for Dummies" is a good enough introductory read for HF+UHF RFID technology. There is also "RFID Toys" (which can be purchased with a 125 Khz reader and a selection of tags); this is pretty interesting and the BASIC Stamp is used in some of the projects in the book.

That about sums it up - but RFID is a really deep and technical subject, so I'd really recommend reading a book or two, if you want optimal results.

Larry

Kyle L. said...
Also, RFID tags tend not to do well around metal or water, so you need to be careful about what you're tagging.

Well that depends a lot on the tag and the reader. A friend of mine here in Oregon is making a VERY lucrative living selling tags and equipment to fisheries researchers. a pretty good percentage of hacheries-bred salmon in the NW are getting tagged and their travels documented pretty well.

They've even put tags on rocks in mountain streams to see how they are carried downstream.

Kyle L.

Larry said...
Well that depends a lot on the tag and the reader. A friend of mine here in Oregon is making a VERY lucrative living selling tags and equipment to fisheries researchers. a pretty good percentage of hacheries-bred salmon in the NW are getting tagged and their travels documented pretty well.

They've even put tags on rocks in mountain streams to see how they are carried downstream.

Right - it depends on the frequency of the tags, if they are passive or active, the reader antenna, tag orientation, and other factors. But, for small scale applications, particularly when proper testing isn't done, metal and water containing objects can cause real problems.

LF can penetrate non-metal object pretty well, so they are often used with water-containing objects (produce, meat, etc.), HF can penetrate metal (to a degree) and the RF waves go around water-containing objects (but objects with high water content can still significantly interfere if the tags are not positioned and oriented properly), and UHF has some trouble penetrating both (which is made up for with the longer read range). There are different tags solutions available to overcome these difficulties, of course.

Each of these frequencies also has different read-ranges (basically, the higher the frequency, the greater the read-range) - depending on the antenna configuration and whether or not the tags are active/passive.

jtrz

Hi all,

Thanks for the speedy and thorough replies. To clarify...

"If I'm going to print my own tags, what are the label specs I should be looking for in RFID tags...for them to work with the Parallax RFID Reader?"

Thanks for the RFID tech references. Not new to RFID. Just to using the Parallax RFID reader.

Thanks,

John

Chris Savage

John,

The specifications for the Parallax RFID Reader are included in the documentation, so I am guessing there is additional information outside of what is provided that you need? If so, what information are you lacking?

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Chris Savage
Parallax Tech Support

jtrz

Hi Chris,

Yes, I read them. That's why I posted here. Just a little confused as to what types of tags it can read.

Page 4 has "RFID Tags Available From Parallax." Page 5 has "Optional Tag Information"

But I was not able to find anything like "...but the Parallax RFID reader is capable of reading any RFID tag with the following specs..."

Buried in the "RFID Technology Overview" page 5-6, I did find the following sentence fragment: "...the Parallax RFID Reader Module's antenna was designed with a specific inductance and 'Q' factor for 125 kHz RFID operation at a tag read distance of up to 1¾” - 3” inches." (pg 6 top)

If I want to encode my own tags, is this the only info I need to know (a) about the reader and (b) about the tags it can read to obtain my own tags?

Thanks,

John

Kyle L.

jtrz said...
Hi Chris,

Yes, I read them. That's why I posted here. Just a little confused as to what types of tags it can read.

Page 4 has "RFID Tags Available From Parallax." Page 5 has "Optional Tag Information"

But I was not able to find anything like "...but the Parallax RFID reader is capable of reading any RFID tag with the following specs..."

Buried in the "RFID Technology Overview" page 5-6, I did find the following sentence fragment: "...the Parallax RFID Reader Module's antenna was designed with a specific inductance and 'Q' factor for 125 kHz RFID operation at a tag read distance of up to 1¾” - 3” inches." (pg 6 top)

If I want to encode my own tags, is this the only info I need to know (a) about the reader and (b) about the tags it can read to obtain my own tags?

Thanks,

John

As I said in my post - the Parallax reader operates at 125 Khz, whereas the Zebra label printers operate at either 13.56 Mhz or the UHF frequencies.

So, you will not be able to print tags with a Zebra printer and read them with the Parallax reader. You would need a reader that works at the same frequency as your printer.

If your printer operates at 13.56 Mhz, then you will need to purchase a 13.56 Mhz reader and tags. For embedded HF reader/writers, I'd recommend the SkyeTek M1-Mini - they cost $80 and do everything you would ever need to. SkyeTek also offers UHF reader/writers.

I've never seen a 125 Khz programmable tag - that frequency is just too low to provide enough power to actually write anything. For that frequency, all you would be able to do is read the unique tag ID pre-encoded in the tag. To encode your own tags, you need to use HF or UHF reader/writers plus the matching HF or UHF tags.

The books I recommended cover all of this, too.

Franklin

Something like this?

[list][*]EM4001 ISO based RFID IC 
[*]125kHz Carrier [*]2kbps ASK [*]Manchester encoding [*]32-bit unique ID [*]64-bit data stream [noparse][[/noparse]Header+ID+Data+Parity]
[/list]

from the SparkFun site.

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- Stephen

Chris Savage

Hello,

The information was located at the top of page 2...As follows:

The Parallax RFID Reader Module works exclusively with the EM Microelectronics-Marin SA EM4100-family
of passive read-only transponder tags. A variety of different tag types and styles exist with the most
popular made available from Parallax.

The following company manufactures the tags we use.· Perhaps you can find more information there.· Take care.

http://www.cyntag.com/

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Chris Savage
Parallax Tech Support