security system using RFID

navychief · 2011-04-03 10:22

I found the attached code from one of the forums and planning to apply it; however it won't activate the RFID to read tags. My tag serial number is 0133C2DD. Help please....

Franklin · 2011-04-03 11:13

So, when you "LOW Enable" it does not activate the reader? Check your wiring and add a few debug statements to see where the program fails.

navychief · 2011-04-03 12:41

I connected RFID pin (Sin) to P0 and (Sout) to P1. Is it correct? Thank you. I'll check the debug.

navychief · 2011-04-03 12:47

I just did the debug and it seems like the program won't pass this command
SERIN RX, T2400, [WAIT($0A), STR buf\10] ' wait for hdr + ID

Unsoundcode · 2011-04-03 14:04

My tag serial number is 0133C2DD

There is something wrong there , the tag number should be a 10 character string.

Jeff T.

navychief · 2011-04-03 14:12

I used this code to get the tag number. Could you please take a look if I did it right? Thank you.

'

[ I/O Definitions ]

RFID_TX PIN 0 ' Connects to RFID R/W Module SIN
RFID_RX PIN 1 ' Connects to RFID R/W Module SOUT

'

[ Constants ]

#SELECT $STAMP
#CASE BS2
T9600 CON 84
#ENDSELECT

Baud CON T9600

' RFID R/W Module Commands
' Number of bytes returned in ()
RFID_Read CON $01 ' Read data from specified address, valid locations 1 to 33 (5)
RFID_Write CON $02 ' Write data to specified address, valid locations 3 to 31 (1)
RFID_Login CON $03 ' Login to tag with password (1)
RFID_SetPass CON $04 ' Change tag's password from old to new (1)
RFID_Protect CON $05 ' Enable/disable password protection (1)
RFID_Reset CON $06 ' Reset tag (1)
RFID_ReadLegacy CON $0F ' Read unique ID from EM4102 read-only tag (for backwards compatibility with Parallax RFID Card Reader, #28140 and #28340) (12)

' Memory map/address locations for EM4x50 tag
' Each address holds/returns a 32-bit (4 byte) value
' ADDR 3-31 are User EEPROM area
ADDR_Serial CON 32 ' Device Serial Number
ADDR_DeviceID CON 33 ' Device Identification

' Status/error return codes
ERR_OK CON $01 ' No errors
ERR_LIW CON $02 ' Did not find a listen window
ERR_NAK CON $03 ' Received a NAK, could be invalid command
ERR_NAK_OLDPW CON $04 ' Received a NAK sending old password (RFID_SetPass), could be incorrect password
ERR_NAK_NEWPW CON $05 ' Received a NAK sending new password (RFID_SetPass)
ERR_LIW_NEWPW CON $06 ' Did not find a listen window after sending old password (RFID_SetPass)
ERR_PARITY CON $07 ' Parity error when reading data

'

[ Variables ]

buf VAR BYTE(12) ' data buffer

idx VAR BYTE ' index
idy VAR BYTE
counter VAR WORD

'

[ EEPROM Data ]

'

[ Initialization ]

Initialize:
PAUSE 250 ' let DEBUG open
DEBUG CLS ' clear the screen
DEBUG "Parallax RFID Read/Write Module Test Application", CR,
"

", CR, CR

'

[ Program Code ]

Main:
DEBUG "Reading tag's unique serial number..."
Read_Tag:
SEROUT RFID_TX, Baud, ["!RW", RFID_Read, ADDR_Serial] ' Read tag's serial number
SERIN RFID_RX, Baud, [STR buf\5] ' Get status byte and data bytes
IF buf(0) <> ERR_OK THEN Read_Tag ' If we get an error, keep trying until the read is successful
FOR idx = 1 TO 4 ' Print data
DEBUG HEX2 buf(idx)
NEXT
DEBUG CR

PJAllen · 2011-04-03 14:28

Are you using 28140 or 28440 ?

navychief · 2011-04-03 14:37

I'm using 28440 reader. Thank you for checking my post.

Unsoundcode · 2011-04-03 14:48

Try this and see if you can retrieve the number

buf VAR Byte(10)
x VAR Nib

main:

LOW 0

FOR x=0 TO 9
buf(x)="-"
NEXT

SERIN 1,396,[WAIT($0A), STR buf\10]

DEBUG STR buf\10,CR

PAUSE 500

GOTO main

Jeff T.

EDIT forget the above and excuse me for jumping to conclusions . The above deals with a different reader.

PJAllen · 2011-04-03 14:48

Then you should be using the sample/source code for that unit --
http://www.parallax.com/Portals/0/Downloads/docs/prod/rf/28440-RFID-RW-BS2code.zip

navychief · 2011-04-03 14:59

The RFID reader remains inactive green indication. Tell me, connecting Sin pin to P0 is the proper way. I might have wrong wiring here. Thank you

navychief · 2011-04-03 15:52

This is what I got using the File...... rfid_rw_test.bs2:

Parallax RFID Read/Write Module Test Application

Reading tag's unique serial number...01E762A1

PJAllen · 2011-04-03 17:02

Then it's "working"?
In post #1 you stated, "My tag serial number is 0133C2DD" and the source app
bounced back that it's "01E782A1".

I bought a bunch of tags from Parallax, but there was no notation as to their #s,
so how do you know that yours is "...DD"?

PE -- Oh, and, yes
RFID_TX PIN 0 ' Connects to RFID R/W Module SIN
RFID_RX PIN 1 ' Connects to RFID R/W Module SOUT

navychief · 2011-04-03 17:07

My bad, the 0133C2DD is my first tag then I tried different one 01E782A1. How come that Low Enable or Low RFID_TX code is not working; the RFID won't activate.

navychief · 2011-04-03 17:10

Attached is the wiring setup.

PJAllen · 2011-04-03 17:13

The "$FEEDBEEF" thing?
That's where it's going to reprogram your tag to = $FEEDBEEF.
You have to be using a writable, R/W, RFID tag, a 'read-only' cannot be changed.

PE -- http://www.parallax.com/Store/Accessories/CommunicationRF/tabid/161/txtSearch/rfid/List/0/SortField/4/ProductID/689/Default.aspx

navychief · 2011-04-03 17:17

Yes, is that what I supposed to use in EEPROM table? Thanks for supporting me on this one.

PJAllen · 2011-04-03 17:20

The "eeprom" is (is in) the R/W tag.
Please confirm that you definitely have an R/W tag.

navychief · 2011-04-03 17:23

Yes. I have R/W tag

navychief · 2011-04-03 17:26

Attached is the print out after the source app read/write on the tag.

PJAllen · 2011-04-03 17:26

So, the program is not getting to where the DEBUG prints: "Writing and verifying data to tag..." ?

navychief · 2011-04-03 17:32

It gets to that point I just deleted that part on the second run.

PJAllen · 2011-04-03 17:34

Then what's the problem?
You want to do another number or what?
Help me help you, Chief.

navychief · 2011-04-03 17:38

I can't make this program code to activate RFID to scan tags.

navychief · 2011-04-03 17:40

I would like to use the RFID to control lock/unlock of door lock using a designated tag.

PJAllen · 2011-04-03 17:50

OK, I think that is going to work only with the other/read-only/legacy RFIDs.
They have 5 bytes, but the R/Ws have 4 bytes.

I modified the prior program (attached.) It will look for $EF in buf(4).
If you didn't re-write your tag then change the test byte to look for $A1 (or whichever tag you're waving in front of it.)

PJAllen · 2011-04-03 17:56

Crumbs, slight error.
Try this one (it should look for the hex $EF, not "EF")

navychief · 2011-04-03 17:56

I'm just getting Expected THEN on this section:
Check:
IF buf(4) = "EF" THEN Unlock
DEBUG "Go Away!", CR

PJAllen · 2011-04-03 17:58

See #27, I Edited while you were posting

PJAllen · 2011-04-03 18:01

forgot those hex2's

PE -- Please post a screen shot of your results. You're a nice guy, Chief, but I'm reluctant to open RTFs (etc.)

navychief · 2011-04-03 18:23

Thanks PJ, you're the best.

security system using RFID

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