Parallax RFID Reader For Ten Bucks

We  received a tip about Radio Shack putting Parallax’s RFID reader on clearance for around $10. The only reference we could find that indicated Radio Shack sold the reader was a review page. The reader originally sold for around $50 in the stores, so getting it for $10 made it worth a curiosity trip to a local Radio Shack. The store we visited did not have the reader marked down in the drawer, but it rang up for $9.97. It is too bad that the reader was so expensive in the first place, otherwise Radio Shack might still be selling them at full price. This is by no means a promotion, we just though we would share the information in case you were interested in getting one yourself. If Radio Shack is out, you could always build your own reader.

The reader we purchased only came with one tag, perhaps that is why the they have been on clearance. Hooked up to an FTDI USB to serial cable, it would repeatedly send out the tag’s number whenever it was in range. We tried an HID-labeled card and a tag of the kind that can be found in books and DVD cases. Neither worked with the reader, but we’ll keep looking.

Thanks to [bluewraith] for the tip.

102 thoughts on “Parallax RFID Reader For Ten Bucks

  1. What tag type did yours come with? And where in the store did you find yours? If the part number is no good online, will i be able to call in to my local stores to check if they have any in stock?

  2. Hi!
    The one I bought some months ago was already on clearance. As it happens it was only half the regular price and with two RFID cards.

    I imagine there might be something to it.

    Incidentally the cards that you tried may have been set for other frequencies.

  3. Got a couple last week, both with some random tags. Fired it right up with a Bus Pirate since I only have 3.3V USB-to-serial converters. Works ok, but I noticed that it will spontaneously spit out bogus codes, maybe 1 every 10 minutes or so. I don’t know if it’s cell phone interference or just some quirk.

    Side note: the tag in books and DVD cases are not RFID. They’re tuned loops that are designed just to set off the detectors.

  4. Also, HID makes a TON of RFID stuff. Do you happen to know what model/line/classification of tag you were using?

    i have tags from them that work in both the 125 KHZ and the 13.95 MHZ bands, and based on a little research, this parallax reader works with 125 KHZ. If you look at the data sheet parallax provides, they mention ” The Parallax RFID Reader Module works exclusively with the EM Microelectronics-Marin SA EM4100-family
    of passive read-only transponder tags. ”

    Which, according to this data sheet :

    the em4100 series is 125KHz.

    I do not know if any/all 125KHz chips will work or if the reader is looking for a specific sequence or ID before it sends out the tag it receives.

    I am really looking to make one of the RFID beer fridges they featured on SYSTM a while back.

  5. Bought one at MakerFaire. Was really bummed that of all the tags i had in my room from various objects, it would only read the tags it came with. btw, the package i purchased had some disk tags, 2 cards, and a keychain tag. It cost well over 10$.

  6. “a tag of the kind that can be found in books and DVD cases. Neither worked with the reader, but we’ll keep looking.”

    The HaD editorial process is always amazing to me. How does the dude who doesn’t know what RFID is get assigned the RFID article?

    Anyway, I will have to go around the local Radio Shacks and see if they have any of these left. I have seen them on previous trips, but always dismissed them because of cost; though I am pretty sure I saw them for $30 and not $50, so perhaps this has been a steady price drop.

  7. I’ve seen elsewhere that they have been marked down for a few months. I picked mine up last week on a parts run. I noticed it hanging there with a sale tag on it and figured what the hell, its only $10. The package had already been opened, so I figured that was why. When I did some more research on it, I found a forum posting stating that all the stores had them on clearance. Some stores may have not updated the shelf talker, but it will still ring up at $9.97.

    I wish my local RS had more. I never messed with RFID before, but at a $10 entry cost I think I have some pretty good ideas on what to use them for. Defiantly going to be on the lookout for them when I travel though.

  8. I can verify this, the Parallax RFID reader and a few other things have gone on Clearance just recently. I remember putting out the tag for it. I’ll get some exact pricing on a couple things tomorrow during my shift.

  9. I’d love to get my hands on one of these for that price but there isn’t a radio shack for at least a hundred miles from here and there’s no listing for it on their website…

  10. @tripp
    I also heard about the TSL230R Light to Frequency Converter being marked down as well, but considering its only a couple of bucks to start with its not as great of a steal. What I’d like to see is the PING))) module come down. My local has about 5 or 6 of those in stock.

    Get buddy-buddy with someone on a forum somewhere?

  11. As stated above, the reader is limited to reading ASK Manchester encoded EM4100/4102 tags only. If you need to read (or clone) HID type access cards then you would need an RFID FSK device like is described at

  12. Sure they are $10. Sure they are cheap. But really, how useful is this thing? If it can only read one thing at a time, at very close range, I don’t see why you couldn’t just use say, an analog pin and resistor ladder.

    I am very tempted at $10 but I see no use for RFID.

  13. @chango,
    a lot of books and dvds do just have tattle-tape, but more and more libraries are using true RFID (13.56Mhz). Those ones won’t work with this 125Khz reader.

  14. Anyone have the clearance item number for this thing? The reader no longer turns up in a product search since it’s on clearance. They didn’t have any at my local store and employees need the clearance item number to point you to a nearby store that does have it.

  15. Just picked up two of these at the 2nd RadShack I visited. I’m hoping to eventually build a reader/spoofer to get free parking in one of the many overpriced garages near me in Atlanta (or at least clone my roommate’s $68/month pass). I know i’ll need different hardware but these should provide a good starting point.

  16. Here’s the clearance item number. Call ahead to make sure they have some in stock first, or to find another location that does.

    RFID Sendor Module ($9.97) 2760032

    And yeah, the light-to-frequency converter is on clearance too. Not a huge deal but still cool.

    Light to Frequency Converter ($1.97) 2760034

  17. I also picked one up. Thought about buying the other one they had, but I figured there must be another hack a day reader in my area who could use one. The price was still marked as $50 and I can confirm the markdown will be taken at the register automatically.

    Thanks bluewraith and hack a day!

  18. Just picked up one…got it working in <10 mins on a bread board w/ usb to serial converter… It has good range as documented…it does occasionally spit out garbage IDs though… generally with a lot of zeroes…but not too often.

    0F03039100 – good
    C00000C000 – garbage
    F000F00000 – garbage
    F0000F0000 – garbage
    F000000001 – garbage

    Don't have a use for it yet… but at $10 it's nice to have in the parts box. Came with credit card style and disk/token style tags (one of each).

  19. Went to Cookeville, TN radioshack – can confirm that it does ring up as ~$10.00 (it was more like $9.90)

    The manager was confused and called up another radioshack to verify. Came out with 2 readers for 25 bucks :)

  20. I picked up one in queen ann seattle. rang up 9.97USD and the guy working there was really confused as to why they’ve sold so many of them lately. Was asking me if there was some weird competition or something going on.

  21. Got it working with the Arduino as an auth device. Seems like it has a noticeable read delay but that might just be a quirk in my code. There’s some example code in the Arduino playground, but that wouldn’t have been fun, so I decided to reinvent the wheel. The garbage data hasn’t been an issue since the key transmission is encapsulated by start and end constant bytes. Just have to read the key twice to be sure we’re not authenticating a monkey at a typewriter.

    I’m thinking I’ll throw this into a motorcycle with a push-button starter that only works if I’m sitting on the bike. That should confuse people enough for a little entertainment. I’ll have to make sure that’s legal in my area (or not). Also, I agree with previous posts that the range might be a concern.

  22. I have been wanting to play with Arduino and RFID, but didn’t think about using them together. This price markdown got me excited, and somehow left the Radio Shack with 7 of the little buggers.

  23. Forgot to mention I only got one tag with mine. Static bag was ripped, though RadioSlack packaging was still intact.


    It would appear the aux chip (EM4095) is capable of writeback via an extra I/O pin that’s currently grounded. And the rest of the unit runs on a PIC16F627A. Interesting.

  24. I grabbed the last two from my former store.
    As soon as I read the article I grabbed the wife and shot out there to say hi ho to my former boss and grab those things.

    Might be fun in the future.

  25. i got it the other day, i went to radioshack, got one, brought it hoe, it didnt work, returned it, that one didnt work, returned that one, got a new one, didnt work. RETURNED IT AGAIN, got one with a chip resistor missing, and i finally complained to the manager, he would not refund me because it was supposedly my fault that the chip resistor was not there. i pointed out that this thing looks wave soldered, and there was no solder on the contact pads of the board, he rudely gave me a credit card, with a $3 restocking fee. I will never go back.

    I will never go back their because the service is crap, prices are marked up terribly high, and thier products are failures!

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