Hello to everyone on this forum. This is my first post and I'm gonna ask you for help with my new project. I have 5 Arduinos UNO (one is a MASTER, the rest four are SLAVEs).
There are one RC522 RFID reader connected to each other of the slaves. Each slave has to read the UID number, decode it and send proper message to the master. Message will look like "C1S1". It will be a String.
Solution has to be very stable. Messages will be send once/twice a day so I think that there won't be colissions [u]but first I have to send any message[/u] between three Arduinos. I tried with UART but It works only with one slave. When I connect next slave messages don't come to the master. I suppose that It doesn't work because you just can't connect two wires to one RX pin in master Arduino.
What is the best way to send messages like "C1S1" from one Arduino to each other? Please give me advice how to start with this project.