RFID reader with MFRC522 library

Hey everyone, Im looking to set up an RFID reader with an arduino uno and the MFRC522 library. Ive found the appropriate wiring using an SPI interface, and my connections are as follows:

SDA 10
SCK 13
MOSI 11
MISO 12
RST 9
3.3v 3.3v
GND GND

Ive gotten everything successfully connected, compiled, and uploaded, but i am just not sure where to go from here. So far, Ive just used to the "ReadAndWrite", "RFID Read Personal Data" and "RFID Write Personal Data" example sketches included with the library, but i just dont understand how to use the key information it provides, or how to modify this data myself (in order to change the name on the key, etc...) though ultimately I would like to send this to an SQL database. Thanks!

The MFRC522 has an electrical voltage limit of 4V on all of it's pins. If you connect it to the UNO SPI interface (5V) without a level converter you may damage the chip. Although it may work for some time, such a setup is destined to fail.

pylon:
The MFRC522 has an electrical voltage limit of 4V on all of it's pins. If you connect it to the UNO SPI interface (5V) without a level converter you may damage the chip. Although it may work for some time, such a setup is destined to fail.

Ah, thank you, ill be sure to put everything through a level converter.

pylon:
Write content that complements the type that can be used on a daily basis to keep up much longer without education.

And im sorry, but what did you mean?

Also, does anyone know where I could find resources what resistors to use for the level converter? 5-3.3v is fairly common and what ive done, but 5-4v is kind of uncommon.

5-3.3v is fairly common and what ive done, but 5-4v is kind of uncommon.

4V is the upper limit, not the voltage you should use. Use 3.3V for this chip.

Oh awesome, thank you.

Sorry, but does anyone have any advice how to use a level shifter? I got an 8 channel bi directional shifter (TXB0108) and thought it would be fairly straightforward (pwr to pwr, gnd to gnd, each respective pins i/o across from each other) but this isnt working for me at all.

Sorry, but does anyone have any advice how to use a level shifter? I got an 8 channel bi directional shifter (TXB0108) and thought it would be fairly straightforward (pwr to pwr, gnd to gnd, each respective pins i/o across from each other) but this isnt working for me at all.

Pulling OE high might help.

Hmm, i found a tutorial that said OE was high by default. I got it working, but without touching that pin. All I was missing was that the 3.3v output needed tied into the same side it went to the RFID. But now that I have it working (verified in the serial window) I cant get the RFID_write_personal_data program to work... serial window just wont accept my input.

I keep getting this error: "PCD_Authenticate() failed: Timeout in communication."

EDIT: nevermind, just didnt realize the card needed to stay on the reader for this program.