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RFID Tag - 125kHz

Replacement:COM-08310. We're carrying the non-branded cards now, check 'em out! This page is for reference only

This is a basic RFID tag used for presence sensing, etc. Works in the 125kHz RF range. These tags come with a unique 32-bit ID and are not re-programmable. Card is blank on one side, smooth, and mildly flexible.

**Replaces: **COM-08310

  • EM4001 ISO based RFID IC
  • 125kHz Carrier
  • 2kbps ASK
  • Manchester encoding
  • 32-bit unique ID
  • 64-bit data stream [Header+ID+Data+Parity]
  • 2.13 x 3.35 x 0.03" (54 x 85.5 x 0.8mm)

RFID Tag - 125kHz Product Help and Resources

SparkFun RFID Starter Kit Hookup Guide

May 5, 2015

Learn the basics of how to get started with the SparkFun RFID Starter Kit.


Looking for answers to technical questions?

We welcome your comments and suggestions below. However, if you are looking for solutions to technical questions please see our Technical Assistance page.

  • Exactly why did you replace the perfect neutral all-white-on-both-sides cards with these? Who did request the printing?
    The all white ones was super useful. These are much less useful.
    PLEASE give us the neutral alternative back.
    And it must be cheaper for you without the extra printing.

    • I agree, it's fantastic to see your branding but in this case it just adds nothing more than problems. Please offer the neutral alternative.

    • Yep, somebody screwed up. I was planning to save myself some time, not worry about the cost, and just buy a bunch of these and issue them to our employees, use them as electronic travelers, etc. Now SparkFun's whacky decision to brand these has got me looking for alternate sources without the branding, and of course now I'm finding all sorts of cool, inexpensive rfid stuff from other vendors. If someone was thinking that the branding will generate more sales, I think they got it backwards.

    • As much as I love SparkFun swag, I must agree. I used to put them through an I.D. card printer, worked well. Cannot do that anymore...
      I would prefer to support you guys as opposed to whoever I can get the white ones from.

      • I agree. I used to buy these from Sparkfun as they were perfect for printing on for my own purposes. Now I have to resort to sourcing them elsewhere, I have absolutely no use for SparkFun branded RFID cards.

    • Agreed. Don't you have the white option anymore? I'm looking for a TAG for ID-20 reader, for a small size prototype, and I don't want the red stuff in my cards, I need to personalize it!

    • if you need an blank rfid card and you live in Australia take a look at this link


  • Is it possible to have spark fun print a custom (customer supplied) design to be printed on these tags?

  • So, the lingering question remains, will these be restocked as printed or plain vanilla?

  • Where do you have your tags printed? I've bought all my RFID stuff from you for a kegerator project at my office. Now I need to print up custom tags (unfortunately they can't be branded SparkFun, despite my wishes). If you could help I'd really appreciate it. Thanks so much.

  • Hello, i would like more than 3 inches, i need 4 meters. Can i use it ?What sould i use ?

  • does the card with the arduino shield (DEV-10162)

  • Does this work with HID miniprox readers?
    i'm worried about the data stream length.

    • I had got a few of these to try and work with my HID ProxPoint Plus reader, and so far no go. I do not see any information saying that the ProxPoint works with EM4001 cards. The MiniProx will fall into this category.

  • dear all i need your help. I reader the tag from the USB reader with serial 9600 and i get a value with 12 digits?
    are these 12 digits in HEXADECIMAL?
    so if i want to convert it to ASCII??
    I'm trying to make a simple program with pic16f628a in order to read the valid tags i have stored in EEPROM and the ones that are not on the EEPROM table to be rejected.
    But i get all the time an error and not accept any tag.
    Do i need to deocde the manchester encoding?

  • Are these going to be restocked anytime soon?

  • I recently used these with the ID-12; in case it's interesting, I found that if I shined a light through them I could see the antenna and chip layout inside, and also that I could trim off a fair portion and still have a working card.

  • I have an RFID reader which supports EM4100 compatible read only or read/write tags. What I want to know is that can these SF RFID tags be identified by the reader that I have?

  • is this read writable by any chance

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