Lazy Man’s USB RFID Reader

c_674_usbrfid5 (Custom)

[Don] had some Serial RFID readers that he needed to work and be powered by USB. He went out and purchased a simple serial to USB converter, but was left with the problem of the operating voltage. He supplies the schematics on his site for his solution. Basically he gutted the converter and integrated it all with the appropriate voltage broken out. The final project is nice, using the serial to USB convert as the project box and even including a nice LED to show when an RFID tag has been read.

12 thoughts on “Lazy Man’s USB RFID Reader

  1. Nice to know I am not the only cheap bastard de- soldering/RECYCLING IC’S opposed to purchasing them.
    This is why GOD invented solider wick.
    One of the most “realistic” projects recently posted.
    Thankx ☆CABLE KRAFT☆

  2. even easier solution is to use a off-the-shelf USB-TTL cable, and forget worrying about the UART-TTL conversion at all:
    $13 from here:
    or $20 from here:

    both of these are already at the TTL level, so no max232 is required, and they alrady provide both 3.3v and 5v easily accesaable on their connector pins ( as well as tx,rx,dtr, and gnd). connect just three wires: 5v,rx,gnd to the rfid reader, and you’re done.

  3. On the subject of RFID, does anyone know how to sense RFID chips from a distance and tell the signal strength? don’t need to read the information from an RFID tag but just sense that there’s one in a vague area.
    Much like how the system works, but much cheaper.

  4. @mem.namefix: yeah I thought that was kinda idiotic too, until I also figured out he has a jar of dirt and nobody could guess what’s inside it.

    @guy with all the stars in his name(unicorn sissy style): A lot of people do, just decent chips only come in expensive devices.

  5. Takes one to know…;)
    I have not seen any correlation between device cost and “chip quality”.

    All of my chips are extremely indecent.

    Just how do you define a “decent chip”?
    It’s either w.a.d. or not.
    When comparing datasheets of identical ic’s from different manufactures there are very few differences.
    Mr. ☆ hooker ☆
    ☆☆sikdidit☆☆ :*)

  6. @SIKDIDIT: A chip that has no application in planned designs. Good voltage controller, application processors, dsps, dacs etc aren’t in cheap devices you get from dollar stores or a good will..

    Passive components are usually all that’s used around an epoxy covered die.

    I also recycle components unless I’m doing work with expensive application processors or something.

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