lock. You’ll need to move it in this case.
If the RFID doesn’t work, check the connections and
make sure no metal is blocking the signal. If you are using
the protoboard, make sure that you change one of the tag
numbers that are represented at the bottom of the
program to match your own tag. Otherwise, it will not
work. Use the object here to get the tag number:
http://obex.parallax.com/objects/332/.
After changing the pins to comply
with the ones you are using, run the
program on the Propeller chip. You
will have to remove the Access
Granted/Access Denied section of the code so the RFID
code will show on the display. If you have any other
trouble with construction/coding issues, feel free to
email me.
on soldering the board to the
bottom of the LCD. This is not
recommended, however.
• If there’s a fault in your
LCD or board, you won‘t be able
to remove the LCD very easily. So,
before you solder, make sure that
the components fit. Also, the
RFID reader MUST be facing out.
If the RFID reader fits over the top
of the circuit board and faces
down into the box, it will not
work properly. Remember that
RFID readers are blocked by
anything metal (EMI suppressant).
This means that the circuit board
you are using will block the
signals. The RFID reader should
hang over the side of the board. If
the box is too short for this, have
the RFID reader on the bottom of
the board and mount it about 3/4
inches off the underside of the lid.
• Remember if sheet metal is
used, keep it out of the path of
the RFID reader. The RFID reader
must not be more than 1-1/2 in
( 3 cm) away from the scanning
area, since the type of reader we
are using here has a maximum
scanning distance of 2-1/2 in
( 5 cm).
• If you are using your own
micro and/or writing your own
program, use a standard servo. A
continuous rotation was all I had,
so I made do.
• Check for project updates
at http://designedbymemicros
. blogspot.com/. I hope you enjoy
it as much as I do.
July 2010 33
