Fritzing

How to connect a 16x2 display (Fritzing Super Upgrade Kit) and a RC522 to an Arduino using a breadboard and read the ID of a tag or card (in decimal numbers)

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I used an Arduino Uno V1, took the RFID-code from here: http://www.electrodragon.com/w/File:Rfid-master.zip and copied it into my libraries folder

(follow the path to your arduino.exe and look for the libraries folder, in this create a new folder, maybe RFID and copy all files from the Zip into it, you have to restart the IDE after that)

and combined it with the code for the 16x2 Display (mine is blue, but it's all the same). You'll also need a 10kOhm poti and a 220Ohm resistor and of course lots of wires :)

The RFID-RC522 is the non-expensive version "Made in China" from Ebay. It seems it can only read V1 tags.

Pin connections: RFID (you can read "RFID-RC522, pins from left to right) - 3.3V (to Arduino 3.3V) - RST (to Arduino 9) - GND (just a minus) - IRQ (left free) - MISO (to Arduino 12) - MOSI (to Arduino 11) - SCK (to Arduino 13) - SDA (to Arduino 10) (and don't ask me why they are cross-wired, I don't know if any of these needs a PWM, didn't look into the library because I wouldn't understand anything and the code doesn't have much comments in it for this.)

Display From 1 to 16 - GND (to potentiometer - one of the side with two legs, or, if yours has only three legs on one side, use one on the outside) - VCC (to potentiometer - the outside one that isn't used now or the free one of the two legs) - Vo (to the slider of the poti, that's the lonely one or the one in the middle) - RS (to Arduino 7) - R/W (to poti, where you put the GND wire of the display) - E (to Arduino 6) - DB0 (left free) - DB1 (left free) - DB2 (left free) - DB3 (left free) - DB4 (to Arduino 5) - DB5 (to Arduino 4) - DB6 (to Arduino 3) - DB7 (to Arduino 2) - LED+ (Background illumination, use 220Ohm resistor and wire to +5V) - LED- (j-a-m; just another minus, I love jam g)

After loading the ino into the Arduino IDE (only tested 1.0.5 r-2) the display shows in German words that the RFID reader is ready. Hold a tag to it and see the serial number in decimal numbers for 10 seconds. When the number vanishes, you can try the next (or the same) tag.

Do what you want with it, I did never try to understand licenses. But have a look into the original code, I didn't find something nasty but maybe it is hidden somewhere?!