Interface with RFID module not working

I am building an automated cat feeder from these instructions at

I have just started reading a book on programming the Arduino, so a programmer I am not. Not yet.

The author of the instructable has provided sketches for testing various systems prior to final assembly. I have run 4 of them successfully, but I have a problem with the fifth sketch, which tests the Seeed Studio RDM6300 RFID module. Here’s the sketch:

And here’s the data sheet on the RDM6300:

The sketch compiles nicely but on upload I get this error message:

Binary sketch size: 5,280 bytes (of a 30,720 byte maximum)
avrdude: stk500_getsync(): not in sync: resp=0x00

I did the wiring of the RDM6300 per the author’s instructions:

If you use a Seeed studio RDM630:
Connect the TX pin of the RDM630 to the RX (pin 0) of the Arduino
Connect the +5V pin of the RDM630 to the +5V of the Arduino
Connect the GND to the GND of the Arduino

Although the author specifies the model RDM630, I am using an RDM6300, which is an improved model, plug-in replaceable.

What does this error message say about what’s going on?

I suspected that the RDM6300 was not working, so I bought another one but got the same result. Don’t be afraid to tell me that I have TWO bad RDM6300s. I can always take a stress pill : ))

While uploading, disconnect the RFID module from the Tx/Rx pins.


Please email for confirming the RDM6300 doubts. Please send along with this post link for reference. Thanks!

Best regards,


The RDM6300 is now a discontinued product.