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Parallax RFID 28440 Rev. A — Parallax Forums

Parallax RFID 28440 Rev. A

winduxwindux Posts: 7
edited 2012-08-15 14:57 in General Discussion
Hi guys,


Can you tell if i can use the Parallax RFID Read Write module with USB2SER connected on computer?

I have purchaged both products but i am not able to communicate with the RFID from the terminal software.

:nerd:


best regards,
Windux

Comments

  • FranklinFranklin Posts: 4,747
    edited 2012-08-15 08:15
    How do you have the two devices connected?
  • skylightskylight Posts: 1,915
    edited 2012-08-15 09:41
    Is it a direct connection or are you going via a Basic Stamp? if the latter there will be a signal incompatibility as the stamp needs an inverted signal
  • Mike GreenMike Green Posts: 23,101
    edited 2012-08-15 10:22
    It looks like you should be able to connect the RFID Read/Write module to the USB2SER module. Remember that Tx should connect to Sin and Rx to Sout since Tx and Rx are relative to the USB2SER module. You also have to set your USB serial port to 9600 Baud. The grounds of the two modules have to be connected together.
  • winduxwindux Posts: 7
    edited 2012-08-15 13:39
    Franklin wrote: »
    How do you have the two devices connected?



    Yes, i am trying to connect the RFID with USB2SER directly to a USB port from my computer using Putty as Terminal.
    When i press any key from the keyboard, a blue light blinks on the USB2SER device but no input or output from RFID module.


    best regards,
    Windux
  • winduxwindux Posts: 7
    edited 2012-08-15 13:42
    Hi Mike,

    I have tried from many ways connecting both devices without success.

    My connections are like this:
    COMPUTER USB PORT -> USB2SER -> RFID

    No luck with this hardware :(


    best regards,
    Windux
  • winduxwindux Posts: 7
    edited 2012-08-15 13:44
    Hi Franklin,

    The two devices are connected directly: RFID=>USB2SER=>USB COMPUTER PORT

    THe Baud Rate are correct 9600-8n1


    best regards,
    Windux
  • PublisonPublison Posts: 12,366
    edited 2012-08-15 14:02
    I guess, what is being asked is, which particular pins on the RFID are connected to the USB2SER.

    Can you provide a picture?
  • winduxwindux Posts: 7
    edited 2012-08-15 14:15
    Publison wrote: »
    I guess, what is being asked is, which particular pins on the RFID are connected to the USB2SER.

    Can you provide a picture?

    The connections is:

    RFID <-> USB2SER
    VCC<->VSS
    SIN<->RX
    SOUT<->TX
    GND<->RES

    I have already inverted the connection and the result is that RFID Led is always ON.


    best regards,
    Windux
  • Mike GreenMike Green Posts: 23,101
    edited 2012-08-15 14:28
    You have them connected incorrectly and may have damaged the RFID reader. As I mentioned earlier, SIN - TX, SOUT - RX and GND - VSS are the proper connections. RES is not connected. You will need a power supply for the RFID module that supplies regulated +5V with at least 200mA available current. You'll connect +5V to VCC and the power supply ground to both GND and VSS.

    There are other USB to serial adapters that provide regulated +5V from the USB bus, but the USB2SER adapter does not do this. Many such USB adapters will only provide up to 100mA which is not enough for the RFID module. You'd need an adapter designed to provide at least 200mA.
  • winduxwindux Posts: 7
    edited 2012-08-15 14:48
    Hi Mike,


    Can you suggest me one adapter to connect my RFID?

    best regards,
    Windux
  • Mike GreenMike Green Posts: 23,101
    edited 2012-08-15 14:57
    I use this FTDI cable (TTL-232RG-VSW5V-WE) for this sort of thing. The cable has a built-in USB to serial adapter for +5V devices and supply +5V at up to 450mA. You can order it directly from FTDI or from their distributors. Digikey, Mouser, and others carry it.
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