What is the best protocol for transferring data between multiple Arduinos?

Question

Arduino

I'm thinking of using i2c, but I'm not sure how well it works with a cable length of say 10-15 meters, who can advise what? The task is to send simple commands to devices (I think 4-6 bytes per second maximum) and receive simple statuses from them (4 byte is also enough). There should be about 20-30 devices in the system, each should have its own "address" in order to communicate with it. A minimum of hardcore is desirable, so that there are libraries for duina, because after designing the system will still be accompanied, and perhaps not by me, everything needs to be simpler.

Answer 1

RS485 out of the box fully satisfies your requirements. You only need to attach a TTL<-> RS485 level converter to Rx/Tx.