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Wireless mesh networked sensors have invaded the wine country of Northern California, USA. Pickberry Vineyards, a 30-acre premium grape grower, is a family-run business in the Sonoma Valley. Pickberry serves as the field-testing ground for an innovative wireless remote sensor network.
Accenture, a global management consulting, technology services and outsourcing company, used a proprietary 900 MHz wireless technology based on Millennial Net's mesh technology. It collects data from electronic sensors - measuring soil moisture, leaf moisture and air temperature - sends it over the Millennial Net mesh network at the vineyard and then via a cellular network to a server at the Accenture Technology Labs, the technology research and development organisation within Accenture. There it is turned into useful information that could eventually help the vineyard increase yields, cut costs, reduce dependence on chemicals and save on labour.
One of Accenture Technology Lab's reasons for existing is to look at emerging technologies expected to have an impact on businesses in the next five to six years. Accenture is interested in the whole idea of taking physical events and starting to track those in a digital realm.
For this field-test, Accenture pulled together radio frequency technology; sensor technologies, that are attached to physical objects and that allow tracking of conditions at a much higher level of detail than could ever be done before; and, ad hoc or mesh-style network technology. It all came together in the proof-of-concept project dreamed up by Accenture Technology Labs and proposed to Pickberry's owners. It was a proposal that could not be refused given that Accenture was offering to develop the system and implement it at no charge.
Mesh network
To cover Pickberry's entire 30 acres, Accenture used the Millennial Net technology to build a mesh wireless network that 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. Because the network is self-organising, adding new nodes, with no configuration work required, means it can easily be expanded.
The Accenture team developed ruggedised and waterproofed sensor nodes the size of a small brick and placed 30 to 40 across the Pickberry acreage. Each one includes a Millennial Net Endpoint - low power radio transceiver, 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. So Accenture 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 pinhole at the bottom of the bucket tipping a 'teeter-totter' device below, measuring rainfall by tilts of the seesaw.
The Millennial Net technology is designed to run on extremely low power. The whole system is powered by a couple of D-cell batteries that will last for six to 12 months. Accenture designed and developed 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.
Low power requirements and long battery life are the main reason for not using Wi-Fi. If you look at Wi-Fi and Bluetooth, complex network handshaking is required and that takes a lot of power to do. Millennial Net's ad hoc mesh networks require only very lightweight handshaking. There is a quick wake-up to collect data and send it and then it turns off. The radio transceivers 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.
The raw data from the sensors ends up at a Millennial Net 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 and then applying business rules to produce useful information. For example, 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.
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.
Benefits
At least a year's worth of history is needed to get more advanced rules. With more historical data in place, comparisons of growing conditions versus the previous year can be made. Comparing the data for example, 'it has been warmer in this area than it was last year, so watering patterns might need to be modified'.
The potential benefits to Pickberry and other viticulturists are enormous, although they are just potential at this point. Until the project collects a full year of data, it will not really be known for sure if the technology can deliver the benefits promised, though they are impressive so far.
The wireless mesh networked sensors provide Pickberry with the ability to:
* Make calculated decisions - almost vine-by-vine - thanks to the granular level of the data obtained in near realtime. For example, Pickberry can use the data to adjust watering schedules for a specific area.
* Combine vineyard data with other data sources. This enables Pickberry to manage operations and resources, such as water usage, more scientifically. Live data on soil moisture and air humidity can be correlated with weather forecast data to match estimated water demand with well supply.
* Detect potentially devastating events such as frost, disease and pests early on. Armed with insight provided from sensor applications, Pickberry can take immediate action. These capabilities lead to more effective crop management, lowering costs while raising product quality.
Any additional information made available to the viticulturists is potentially useful. The difference between doing something and doing it well is all in the information one has. So it is a challenge to figure out how to use this information.
The owners of Pickberry Vineyard historically have relied 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 microclimates and 'dramatically' different soil types with different moisture run-off characteristics, so it is not just a question of making one decision for the whole vineyard.
At the simplest level, the soil moisture sensors can tell the viticulturists when particular sections need irrigating and, just as important, when they do not. 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 simple computerised system that lets them schedule turning on and off the water. If data on specific area needs could be loaded into the system and not just a time sequence that would be a very useful thing. Water is a precious resource because there is a limited quantity in Sonoma County and it costs a lot to irrigate.
The leaf moisture sensors could alert the viticulturist to the need in specific sections of the vineyard to apply chemicals, sulphur, to combat mildew. The potential benefit, again, is that the viticulturist would know exactly when and where the chemicals were needed and avoid application unless it was absolutely necessary. Viticulturists would always rather do less spraying than more both for ecological and economic reasons.
Remote analysis
In the wireless system Accenture developed, this information is delivered with great accuracy to any Web-connected computer. The viticulturists do not actually have to visit the vineyard to know what is going on. They can also download the data into a spreadsheet for further processing.
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.
RF Monolithics is a primary provider of low power, long battery life Virtual Wire transceivers in the 900 MHz frequency range for mesh networked sensors like Millennial Net's Endpoints, Routers and Gateways. Mutronics are the agents for RF Monolithics in South Africa.
For more information contact Mutronics, +27 (0)11 608 1460, [email protected]
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