How far of a wire can I attach rc522 RFID module?

I need one reader on each side of the gate, probably about a 20' span. I'm not sure what kind of issues i'm going to run into with this one.

thank you

Please don't open multiple threads.

I'm guessing you use the SPI interface, so just look up "SPI maximum cable length" or something like that

couka: Please don't open multiple threads.

I'm guessing you use the SPI interface, so just look up "SPI maximum cable length" or something like that

google says 10' so this might be an issue for me. what would your recommended fix be?

The fix would be not to piss people off by starting multiple threads on the same topic.

You started 27 threads in less than 2 months.

There's no way you seriously tried to solve all these problems yourself.

I guess an arduino on each rfid board and one with a rs485 board connecting the 3 to control the gate, is my solution

To get a signal over the distance you want you could use a differential buffer like the MAX485 at each end. Like they did here:- https://www.oshpark.com/profiles/PaulStoffregen\

Grumpy_Mike:
To get a signal over the distance you want you could use a differential buffer like the MAX485 at each end. Like they did here:-
https://www.oshpark.com/profiles/PaulStoffregen\

thanks. ill probably be giving that one a try first.