Feb 11, 2007
Read RFID Tags
You can use Parallax RFID reader module to identify object from a large set by hiding RFID card inside it. Basically reader has two signal pins, one out and one in. First is used to enable/disable reading, second is used for reading the card identification number.
We had some issues, as we did not know how to connect RFID reader to Arduino, so we connected it to Basic Stamp board. However, as we needed Arduino for our project also, we had problems connecting two boards to Mac laptop. This was solved by putting wires from Basic Stamp digital outs to Arduino digital inputs, thus reading the RFID through Arduino.
However we still were left with some noise problems (maybe because of long wires between Stamp and Arduino), triggering the card read even though the reader itself was not firing. We achieved to get it to smaller levels by using battery instead of electrical outlet. Some of noise was there still in the end, so we probably should inspect using noise-removal algorithms in the code.
We added this kind of behaviour to Parallax example RFID code (see product page) for rerouting RFID readings (as tag numbers) to Arduino:
Show_Name:
DEBUG DEC tagNum, CR
' send digital 1 to pin corresponding the card number
IF tagNum = 1 THEN
HIGH 11
PAUSE 1000
LOW 11
ENDIF
IF tagNum = 2 THEN
HIGH 12
PAUSE 1000
LOW 12
ENDIF
...
Of course the amount of pins limits the amount of cards, so probably it would be wiser to use variation of voltage in analog signal to separate between different cards. Then again, this might suffer from noise signal, so what to do…
More info from the product Internet pages
Kalle Mäntsälä & Tuomo Tarkiainen
