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RFID No-read BS2 — Parallax Forums

RFID No-read BS2

Luke TYLuke TY Posts: 11
edited 2008-03-31 21:59 in BASIC Stamp
Hey all,

I am having problems getting my RFID reader to read RFID tags. I absolutely definitely have things hooked up properly. Every once in a while when I run the code it detects a tag and displays the info but refuses to do so consistently. I had it up and running perfectly for a couple of times before where it did what it was supposed to do so I know (hopefully) that it works. I am currently using a parallax-brand USB to Serial converter.... I am using sample code directly from the parallax website so I don't think there are any errors there? Anyone else had an RFID work sporadically for them?


Edit: The RFID light is red.

I am currently using this code:

' =========================================================================
'
'   File....... RFID_basic.BS2
'   Purpose.... RFID Tag Reader
'   Author..... (c) Parallax, Inc. -- All Rights Reserved
'   E-mail..... support@parallax.com
'   Started....
'   Updated.... 02 Mar 2005
'
'   {$STAMP BS2}
'   {$PBASIC 2.5}
'
' =========================================================================


' -----[noparse][[/noparse] Program Description ]---------------------------------------------
'
' Reads tags from a Parallax RFID reader and displays ID to debug screen


' -----[noparse][[/noparse] Revision History ]------------------------------------------------


' -----[noparse][[/noparse] I/O Definitions ]-------------------------------------------------

Enable          PIN     0                       ' low = reader on
RX              PIN     1                       ' serial from reader



' -----[noparse][[/noparse] Constants ]-------------------------------------------------------

#SELECT $STAMP
  #CASE BS2, BS2E, BS2PE
    T2400       CON     396
  #CASE BS2SX, BS2P
    T2400       CON     1021
  #CASE BS2PX
    T2400       CON     1646
#ENDSELECT

Baud            CON     T2400

LastTag         CON     3


#DEFINE __No_SPRAM = ($STAMP < BS2P)            ' does module have SPRAM?


' -----[noparse][[/noparse] Variables ]-------------------------------------------------------

#IF __No_SPRAM #THEN
  buf           VAR     Byte(10)                ' RFID bytes buffer
#ELSE
  Char       VAR     Byte                    ' character to test
#ENDIF

tagNum          VAR     Nib                     ' from EEPROM table
idx             VAR     Byte                    ' tag byte index



' -----[noparse][[/noparse] Initialization ]--------------------------------------------------

Reset:
  HIGH Enable                                   ' turn of RFID reader



' -----[noparse][[/noparse] Program Code ]----------------------------------------------------

Main:
  LOW Enable                                    ' activate the reader
  #IF __No_SPRAM #THEN
    SERIN RX, T2400, [noparse][[/noparse]WAIT($0A), STR buf\10]    ' wait for hdr + ID
  #ELSE
    SERIN RX, T2400, [noparse][[/noparse]WAIT($0A), SPSTR 10]
  #ENDIF
  HIGH Enable                                   ' deactivate reader

Display_Tag:
  DEBUG "Tag Identification number is: ", CR
    FOR idx = 0 TO 9                            ' scan bytes in tag

      #IF __No_SPRAM #THEN
        DEBUG buf(idx)
      #ELSE
        GET idx, Char                        ' read char from SPRAM
        DEBUG Char
      #ENDIF
    NEXT
  DEBUG CR
  PAUSE 500
  GOTO main                              ' repeats code



I appreciate any response,
Luke TY

Post Edited (Luke TY) : 3/28/2008 12:28:25 AM GMT

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2008-03-28 16:32
    Running our code (that you have pasted in the message) the LED should turn Green briefly when a tag has been read. Is this happening? Is there anything between the tag and the reader (such as a metal panel)?

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    Chris Savage
    Parallax Tech Support
  • sam_sam_samsam_sam_sam Posts: 2,286
    edited 2008-03-28 17:40
    Luke TY

    How are running RFID Card Reader Board
    (1) are you running the reader off of·the regulator of the Basic Stamp Board
    If this is the case you maybe taxing regulator by over heating it
    (2) You should be Running it on it own regulator with a heat sink if
    you are using 7.2 volts or more
    (3) If you are not using a regulator·for the RFID Card Reader Board·or
    ·The on board regulator on the·Basic Stamp Board to power the RFID Card Reader Board·
    ·That is the vdd termanl then you have fried the·· RFID Card Reader Board which i hope is not the case

    Parameter Symbol Conditions Min. Typ. Max.
    Supply Voltage VCC --- 4.5 5.0 5.5 V
    Supply Current, Idle IIDLE --- --- 10 --- mA
    Supply Current, Active ICC --- --- 90 --- mA
    ·

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    ··Thanks for any·idea.gif·that you may have and all of your time finding them

    ·
    ·
    ·
    ·
    Sam

    Post Edited (sam_sam_sam) : 3/28/2008 5:45:12 PM GMT
  • Luke TYLuke TY Posts: 11
    edited 2008-03-29 06:32
    The RFID reader VCC pin is hooked up directly to VDD and Ground to VSS. I was pretty sure that the RFID reader didn't call for any type of resistor. I'm relatively new in the field of electronics and am not definitive about anything.

    Chris, The light does turn green when a tag is read. It does detect tags but very rare and sporadically.
  • sam_sam_samsam_sam_sam Posts: 2,286
    edited 2008-03-29 07:55
    Luke TY

    How are you placing the card to the reader

    ·Are you putting the card to the center of the cut out on the RFID Card Reader Board·if not try this

    ·Are you using the round disk or the card type with round ones put·at where you see the traces·around ·the cut out· and move to the top off
    the card reader until it reads the card and then leave it until it reads it couple of times

    If you are using the card type just set the card on top of the card reader a Little·more to the top of the card reader this is the end of the card reader that dose not have the pins

    You will know if you have the card in the right place because it keep reading the same number for that card

    It will read a card or disk ·about one every second or so


    Also did you use the pin that are list on the DEMO Code· which would be pin 0 and pin 1 on the board that you are using

    One other thing are you using the plug in part on the white plastic pro-to board if this is the case your connection may not be very good
    a connector that is made for the pins on the board

    One more thing make sure that the card or disk are·as close to the·RFID Card Reader Board as you can and only use one card or Disk·one·at time

    I hope this help·you get the reader to work right

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    ··Thanks for any·idea.gif·that you may have and all of your time finding them

    ·
    ·
    ·
    ·
    Sam

    Post Edited (sam_sam_sam) : 3/29/2008 8:12:40 AM GMT
  • skylightskylight Posts: 1,915
    edited 2008-03-29 09:23
    Are you being patient with the reading of the tags? ie with the id tags we use at work it can take a second or two of holding the tag in place before it successfully reads them.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2008-03-31 15:51
    I’m still curious if the VCC is connected to the BASIC Stamp’s on-board regulator or to the VDD on a development board such as the Board of Education?

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    Chris Savage
    Parallax Tech Support
  • Luke TYLuke TY Posts: 11
    edited 2008-03-31 20:19
    VCC is connected to the VDD on my Homework Board. Did I hook this up incorrectly?

    Followed all suggestions and am still having the same problem.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2008-03-31 21:59
    Luke,

    Please contact Tech Support directly to send the device in for testing. support@parallax.com



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    Chris Savage
    Parallax Tech Support
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