I am fairly new to this, having worked only a bit with Arduinos. I would like to know if it would be possible to connect multiple Arduinos to a raspberry, just to transmit a signal.
Description: A factory has 10 machines, I would like to connect an Arduino to each machine so that when the machines are on it would send a signal to the Raspberry Pi (or even another Arduino), and then it light up a tiny led lamp connected to the Raspberry Pi. Whenever the machines are turned off, the led would turn off. Essentially, the Arduinos would probably be directly connected to the machines power supply in a way.
Would this be possible with multiple Arduinos and transmitters? I would say distances between the Arduinos and the Raspberry Pi would be between 20 to 70 meters.