I am an electornics hobbyist. A friend of mine, who is building an organics farm, wants to wirelessly automate some devices in his property, and asked for ideas.
His problem is to "talk" to remote devices, namely the front driveway sliding door (around 100m away from home) and water pump (200m away from home in the opposite direction). This "talk", that is, sending and receiving commands and data, would be handled by some sort of dashbord or "control center" yet to be devised.
At first, he expressed the desire to use WiFi, but as far as I know, at least the water pump would be too far from the control center.
I am pretty sure this type of scenario is pretty common, but could not find an obvious protocol for the "100+ meters" range, up to, say, 500m or 1km.
What are the protocols commonly used for this, specially in rural areas?
UPDATE: At first, we would not like to depend on third-parties, such as cell-phone operators or similar paid services.