the nodes in the network will figure out how to transmit the data to your gateway computer. If a node breaks or loses contact, the rest of the network will adapt.
There are sensors that keep track of the water pressure in the irrigation system and sensors for wind, humidity and temperature. And most important of all, sensors measuring the “soil water tension”, which can be described as how hard the plant’s roots have to suck to draw moisture from the earth.
The soil moisture tension corresponds to the leaf water potential. (The drier the earth, the thirstier the plants.) The sensor measurements give Holler a way to keep his vines at just the right level of thirstiness, without using too much water, and without worrying that they might wilt.
Holler’s main goal is to conserve water. A neighbor who bought the system reported that he saved 60 per cent on irrigation water the first year.
But it also helps improve quality. “Monitoring raises your awareness of what’s happening in the vineyards,” says Holler. “Most of the problems I’ve seen in vineyards comes from negligence.”
He first started monitoring the vineyard with a wireless weather station. “It was some help, but not enough, he says. “The vineyard has four blocks and I only had one weather station. I needed more data.”
Holler built the first generation of the system with some raw technology from Crossbow. The current nodes—the yellow containers—are called eKo, and are the invention of Crossbow’s chief technology officer, Alan Broad. They are also used in other sensor networks applications, like environmental research. And of course, a very logical step would be to use them for control as well as monitoring—jobs like opening irrigation valves or starting and stopping pumps.
[Editor’s Note: A longer version of this article originally appeared in Mellgren’s publication Ny Teknik. This abridged translation is published by permission.]
