I am doing a little project ( mainly to learn electronic ) where i have RFID reader and i only read the id of the card.However they are a bit too bar from each other ( up to 5 m ) and the I2C communication did not really support really well the long cable. So i am intend to add a Atmega328 to each antenna and send this information to a central Atmega328 that will send the information ( either to a computer or directly to internet with a SIM800L ). So my question what will be the best approach to send message from N arduino ( up to 10 ) to a central arduino over 5 m cable distance. The message is 40 character but is send really often.
All the best