I need to make Arduinos communicate over long distances (at least 0-15m, but it would be great if I could make it work on 0-100m) keeping the cost as low as possible. My speed requirements are not too high - a few KB every few seconds.
I was thinking about connecting Arduino Leonardo's with USB cables, but I am not sure if Arduino can supply enough power to transmit over such long distances. Also I am not sure if they can communicate in peer to peer mode (normally USB is master slave mode). I am also not sure if USB is the right choice here and if the legends about 25m long usb cables are true....
Any advice would be appreciated.