The Wireless Winery
September 23, 2004
This experimental mesh network with RFID tracks the goings on at a California vineyard, but eschews use of Wi-Fi to keep the power requirements at a minimum.
Pickberry Vineyards, a 30-acre, family-run business in the Sonoma Valley in northern California, is not the usual sort of customer for what multinational technology consulting firm Accenture has to offer.
Pickberry was more than happy, though, to serve as a guinea pig for the innovative wireless viticulture system that Accenture associate partner Bill Westerman was developing at the company's technology lab in nearby Palo Alto.
The system does not use Wi-Fi for some intriguing reasons. Instead it uses proprietary 900MHz wireless technology from Millennial Networks. It collects data from electronic sensors — measuring soil moisture, leaf moisture and air temperature —sends it over a Millennial mesh network at the vineyard and then via a cellular network to a server at the Accenture lab. There it's turned into useful information that could eventually help the vineyard increase yields, cut costs, reduce dependence on chemicals and save on labor.
"One of our lab's reasons for existing is to look at emerging technologies we think are going to have an impact on our clients in the next zero to six years," Westerman explains. "We were interested in the whole idea of taking physical events and starting to track those in a digital realm."
"Part of it is RFID (Radio Frequency IDentification). Part of it is looking at sensor technologies that you attach to physical objects and that allow you to track conditions at a much higher level of detail than you ever could before. At the same time we were looking at ad hoc or mesh-style networks."
It all came together in the proof-of-concept project Westerman dreamed up and proposed to Pickberry's husband and wife owners Lorna and Cris Strotz who he knew slightly. It was a proposal they couldn't refuse given that Accenture was offering to develop the system and implement it at no charge to the Strotz's.
Accenture used the Millennial technology to build a mesh wireless network that covers Pickberry's entire 30 acres. It includes Endpoints attached to sensors, Routers that communicate with Endpoints and steer data from them through the self-healing mesh network, and Gateways that interface with other networks and systems.
Westerman's team developed ruggedized and water-proof sensor nodes the size of a small brick and placed 30 to 40 across the Pickberry acreage. Each one includes a Millennial Endpoint — radio, antenna, processor, input-output capability and a small amount of memory — connected to various sensors.
The soil moisture sensor, for example, is a 30-foot wire that goes into the ground. "On the first try, animals chewed them," Westerman says. "We had to come back and harden the wires."
The rainfall sensor is an ingenious device mounted on top of a pole. A tiny bucket collects the raindrops, they fall through a pin-hole at the bottom of the bucket on to a teeter-totter device. Each drop tips the teeter-totter. "So rainfall in effect is measured by tilts of the seesaw," Westerman explains.
The whole thing is powered by a couple of D-cell batteries that will last for six to 12 months. The Millennial technology is designed in the first place to run on extremely low power. Accenture architected the viticulture system so that the sensor nodes "wake up" periodically, capture data, store it briefly and then send it out over the network. Then they go back to sleep drawing hardly any power at all.
Therein lies the main reason for not using Wi-Fi, Westerman says. "If you look at Wi-fi and Bluetooth, there's a lot of [network] handshaking required and that takes a lot of power to do. These ad hoc, mesh networks require only very lightweight handshaking. There's a quick wake-up to collect data and send it and then it turns off. The radios are off as much as possible."
Using a Wi-Fi mesh network would have meant running power to the routers, something that would have been too intrusive and prohibitively costly. WiMAX with its greater range might eventually be useful in similar applications, Westerman says, but it lacks the mesh network capability of getting around line of sight obstacles.
The raw data from the sensors ends up at a Millennial Gateway attached to a laptop computer at the Pickberry vineyard. The laptop is also equipped with a cellular modem. The data is stored on it temporarily and then periodically posted over the cellular network to the Accenture server in Palo Alto.Accenture developed back-end systems for receiving the raw data stream, massaging it — converting 17 ticks on the water buckets to so many inches of rain, for example — and then applying business rules to produce useful information. If the system detects that a section has received a certain amount of rain, it generates an alert to the viticulturist that he can safely turn off his irrigation system, for example.
Accenture has refined the wireless sensor network and basic functions of the back-end system. The next step is further developing the business rules engine.
"You want a year's worth of history to get more advanced rules," Westerman explains. "When you've got more historical data in place, you can start comparing growing conditions versus the previous year. So you could say something like, 'It's been warmer in this area than it was last year, so you might want to modify your watering patterns.'"
The potential benefits to Pickberry and other viticulturists are enormous, although they are just potential at this point, the Strotz's say. Until the project collects a full year of data, they won't really know for sure if the technology can deliver the benefits Westerman is promising, though they're impressed so far.
"I think any additional information that you have is potentially useful," says Lorna Strotz. "The difference between doing something and doing it well is all in the information you have. So it's our challenge to figure out how to use this information."
The Strotz's rely now for the most part on their deep knowledge of the land, gained over 30 years, and regularly eyeballing their acreage to figure out if they need to irrigate or apply chemicals to combat the mildew. The 30 acres include a number of micro climates and "dramatically" different soil types with different moisture run-off characteristics, so it isn't just a question of making one decision for the whole vineyard.
At the simplest level, the soil moisture sensors can tell the Strotz's when particular sections need irrigating and, equally, when they don't. This can help keep moisture levels just right for optimum growing, but also help reduce the vineyard's reliance on scarce water resources.
Pickberry manages irrigation now using a "rudimentary" computerized system that lets them schedule turning on and off the water. "If you could input the need and not just a time sequence, that would be a very useful thing," Strotz says. "Water is a precious resource because there's a limited quantity in our area and it costs a lot to irrigate."
The leaf moisture sensors could alert them to the need in specific sections of the vineyard to apply chemicals, sulfur, to combat mildew. The potential benefit, again, is that the Strotz's would know exactly when and where the chemicals were needed and could avoid applying them unless it was absolutely necessary.
"We would always rather do less spraying than more both for ecological and economic reasons," Strotz points out.
The beauty of the wireless system Accenture developed, Westerman says, is that this information is delivered with great accuracy to any Web-connected computer. The Strotz's don't actually have to visit the vineyard to know what's going on. They can also download the data into a spread sheet for further processing.
"If you were to rank the benefits," Westerman says, "the first, and the one that will have most impact, is that it will help Pickberry produce better grapes and more of them. Second is the further reduction of water and chemical application. The third thing is reducing the amount of labor — although given the size of this vineyard, that's a fairly small factor."
Another potential benefit is that the system could bring a viticulturist up to speed on the growing characteristics of new acreage much more quickly than the usual trial-and-error process of planting vines and watching what happens. The Strotz's, however, who run Pickberry as a part-time business, are not likely to buy any new land. Since they bought their acreage in 1975, land prices have become prohibitive, Strotz says.
She also admits that she and her husband may not be knowledgeable enough in the science of viticulture to make full use of the information the Accenture system is generating, although there is clearly nothing wrong with their native skills. Pickberry sells its entire output to nearby Ravenswood Winery, which uses it to produce one of its top-rated "Meritage" wines.
A wine university in the region is very interested in the Pickberry experiment, as is a local soil analyst — and Accenture already has a much bigger wine growing operation interested. It is also applying what it has learned in the Pickberry project in some completely different applications for its more familiar big industrial clients.
In some of those, Westerman says, where power requirements and line of sight are not issues — monitoring machinery in a factory, for example — Wi-Fi would likely serve very well and be much less expensive.