Scratch built RFID tags


[nmarquardt] has put up an interesting instructable that covers building RFID tags. Most of them are constructed using adhesive copper tape on cardstock. The first version just has a cap and a low power LED to prove that the antenna is receiving power. The next iteration uses tilt switches so the tag is only active in certain orientations. The conclusion shows several different variations: different antenna lengths, conductive paint, light activated and more.


  1. cirictech says:

    This is nifty, may actually be able to apply this.

  2. tony says:

    I don’t usually like what you guys find on instructables, but this is good stuff. Always wanted to experiment with rfid.

  3. fartface says:

    That’s parasitic power NOT rfid. call me when they have one reporting a serial number to a standard reader.

  4. asasdf says:

    a resonant circuit. wow, that’s novel!

  5. strider_mt2k says:

    It’s still cool, even if it isn’t up to the standards of the rest of the peanut gallery.

  6. epooch says:

    “call me when they have one reporting a serial number to a standard reader.”:
    That is exactly what it does:
    “This induced current activates the RFID chip that is connected to the tag’s antenna. This chip then modulates a response (usually the unique ID number) that is transmitted back to the reader.”

  7. static says:

    So it’s more of a RFID reader detector, not a RFID tag, correct?

  8. crimson says:

    @fartface: If you’d bother reading the article, you’d have realised that in step 4 he mentions that the capacitor and led can be replaced by an RFID ic, which will allow them to report a serial number to a reader. Next time, read before you comment shooting down someone else’s work.

  9. fartface says:

    I did not realize that Hack a day gives a free pass to anything by adding the line “Simply hook up X to here and it does this.

    Call me when he does it for real.

  10. jproach says:

    He did actually solder in a mifare 1k RFID chip in the last step (step 5).

    He didn’t mention if it actually worked or what the range was though.

  11. me says:

    geez you guys whine alot. I keep coming to the comments section for unique insight from the community, and what I get is a bunch of Techno-hipsters saying I’m leeter than thou.

    I think it worth noteing that while Instructables is amaturish, High end hacks don’t emerge from the vaccum. Every leet hacker started by goofing off in the garage.


  12. strider_mt2k says:

    word, me.

  13. agrajag9 says:

    Even if it is just a resonant circuit, it’s still a really nifty, quick+dirty hack that anybody can do with very little expertise.

  14. Nic says:

    Hi everyone, thanks for your comments on this project. I’m the author of the Instructable mentioned here, and so I wanted to reply to your comments.
    I agree: this is a really, really simple project, and nothing too sophisticated for anyone who has knowledge of RFID. However, it hopefully illustrates how easy it is for non-experts to still explore this usually invisible technology. It is intended as a starting point, that opens directions for more experiments.

    And to answer the raised question: yes, these tags work with Mifare chips, and yes: the reading distance is in fact very bad (around 2-4 cm). But, considering that we use simple copper tape and a simple antenna layout, it is still surprising that it works (at least for me). The Sonmicro reader receives the unique ID of the chip, and I can write data packages to it. I did many more experiments with RFID, and I hope I find the time to share more of them with everyone who is interested in it. So far, this includes a collection of over 25 various tags, many different sensors, active tags, custom readers, and PCB tags (which are much, much smaller).

  15. vsnine says:

    I’d LOVE to see RFID tags with a button on them so they only work while being squeezed by the user. Would help prevent ‘drive-by’ scans…

    Awesome work.

  16. YLS says:

    I haven’t looked through the work these guys did in detail but where did they get the RFID chips from or did they just take them out of another peice of hardware?

    I’ve been trying to do simular work but all the Tags I get my hands on the chip is usually covered in glue and near impossible to solder to.

  17. Nic says:

    @vsnine: you can see an example for such a tag on the last page of the instructable: the tag (third image) includes a switch that let’s the user manually activate the RFID chip. when the LED lights up, the user can decide if he/she wants to activate the chip.

    @yls: I agree, using RFID ICs from existing RFID tags does not really work because of the glue material around. however, you can easily order RFID chips directly, for instance at, order number 568-2219-1-ND. there are also many other RFID ICs available there.

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