The RDM630 library enables the Arduino to easily read EM4100-compatible RFID-tags using the RDM630 RFID reader module.
Needed hardware for this demo
- Arduino compatible board
- RDM630 RFID reader
- EM4100 compatible tag
How to connect
- Connect 5V & GND of the module to the corresponding pins of the Arduino
- Connect the TX pin of the module to pin 6 of the Arduino.
- You could use another pin of the Arduino, but then you'll have to change the initialisation of the rfid object in the demo code below.
- If you're using a 3V3 Arduino, you'll have to use extra level shifting. A pull-up resistor between the 3V3 and the Arduino-pin, together with a diode between the Arduino-pin (anode) and the RDM630-TX pin (cathode) will do the trick.
How to program
The library can be downloaded from here.
- Create a folder named "RDM630" (without the parentheses) in your Arduino-libraries folder.
- Copy rdm630.h & rdm630.cpp to that folder.
- Create a new Arduino-sketch
- Import the "RDM630"-library into your sketch.
- Copy/paste the following demo application to your sketch
- Upload & run
rdm630 rfid(6, 0); //TX-pin of RDM630 connected to Arduino pin 6
Serial.begin(9600); // start serial to PC
//concatenate the bytes in the data array to one long which can be
//rendered as a decimal number
unsigned long result =
((unsigned long int)data<<24) +
((unsigned long int)data<<16) +
((unsigned long int)data<<8) +
Serial.print("decimal CardID: ");
The first output is actually the CardID encoded in hex.
So e.g. for a CardID (printed on the card) of 0007616525, you will get the following output:
2 0 74 38 D 0
- The leading 2 is the STX symbol (0x2) denoting the beginning of an ID.
- The three leading 0s are reduced to one single 0
- 7438D is the decimal number 7616525 encoded in hex
- the trailing 0 is proof that the checksum that was transmitted by the module matches the XOR operation performed by the RDM630 library on the received data.
The second output is the CardID as a decimal number (as printed on the card).