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The video isn’t exciting but it’s cool, showing the actual spoofing of an RFID signal — the maker’s antenna and an actual RFID tag, both scanning the same.

RFID tags are all over the place. They’re used in building access control systems, passports, inventory tracking…. This instructable will show how you can use an Arduino and a few simple components (wire coil, transistor, capacitor, resistor) to make a device that can spoof an 125 KHz (low frequency) RFID tag. This is version 1, so there are many enhancements that can be made, but this version is stupid simple, yet it works. I did this in a few hours without much previous knowledge of RFID and without any fancy equipment (like a radio tuning hardware or an oscilloscope).

John Baichtal

John Baichtal

My interests include writing, electronics, RPGs, scifi, hackers & hackerspaces, 3D printing, building sets & toys. @johnbaichtal


    Yeah… most people don’t realize how easy the average LF RFID tag is to spoof. It’s great to see more people demonstrating this :)

    I got interested in this a while ago while working on a DIY RFID reader project. I ended up finding some dirty tricks you can use to make passive RFID tags using just an AVR and a coil, no external power source:

    • sketch

      I actually read through your design as I was making mine. Your’s is awesome, it’s amazing what you did with the tiny microcontroller and a resistor. I added your site to the references section of the instructable, I knew I forgot something.

  • Ron Bean

    This is no different from duplicating a metal key– it’s easy to do if you’re motivated, and if you can “borrow” a working one to copy. If you’re worried about espionage, this is a concern. But a burglar is more likely to smash a window, because it’s easier and he’s not worried about hiding the fact that the building has been broken into.