Connect several RFID-RC522 to one arduino, nano, mega, uno available. How?

Question

Arduino

I need to create an rfid network at a short distance from each other, how best to organize it? There is no possibility to take rs485. It is possible to use a separate nano for each rfid, but infa must come to one device, which will then send it to the server.

Answer 1

As far as I know, connecting several RFID-RC522 to one arduino is a problem. So the arduino is not a reader. further options:
1. The serial port per meter is likely to work. Therefore, we connect the arduins with a star, TX first to the RX of the others, TX of the rest through diodes to the RX of the first, arduins 2-5 transmit their number and, due to possible collisions, must receive a confirmation of receipt. Another option is a ring. 1-2-3-4-5-1, with packet relay, but without additional. details.
2. The I2C bus for some of them even started up to 5 meters, although formally its limit is several tens of centimeters. The first master, the rest are slaves. You need 2 pull-up resistors.
3. 1Wire protocol. It takes ten meters, you need 1 pull-up resistor. I once met the slave's 1Wire libraries on the net.