I recently built a sensor using the code listed above and everything seems to work fine. However, I do have a problem with it recognizing one of my RFID tags as being valid. When I scan the tag it comes back with the key 0x33, 0x92, 0x94, 0x0, 0x00, 0x00, 0x00. I have included this key in the code for valid keys but the tag will not activate the lock since it's not being recognized as valid. I suspect the issue is with the 4th part of the key being 0x0 rather than 4 bytes. While I understand some programming, Arduino code is new to me and I'm also not fluent in hex codes.

Wondering if anyone can offer a simple solution.

Thanks.