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Linking, managing, calibrating: the latest developments of data-driven Connected Green

Green monitoring platform ConnectedGreen has evolved into a ‘serious company’ within a few years after their inception

Early 2017, René Voogt presented his green management app ConnectedGreen for the first time at the Green Sector Trade Fair in Hardenberg. He presented a prototype to the “great names” of the green sector – and the first pilot projects were agreed upon. A year later, the moisture monitoring system with wireless sensors was unveiled. During the 2020 edition of the fair, trade magazine Stad + Groen visited the ConnectedGreen booth again. We spoke to Voogt, now for the fourth time at the spacious fair, about the latest developments. “The conversations that we have, are very different now compared to previous years.”

Auteur: Karlijn Klei

The slogan that characterizes ConnectedGreen has not changed in those years: ‘It is not just about the sensor … but about what you do with the data.’ ‘You should see ConnectedGreen as a platform for interpretation and sharing information from sensors for (public) green’, is how Voogt starts our conversation on the exhibition floor. The system leverages expertise in the field of trees, plants and soil types. The smart monitoring helps to work more sustainably and to save both on water and on project visits. This reduces costs and provides some relief around the shortage of staff in the sector.

Water, light and temperature

‘We are reselling sensors from 3 suppliers,’ says Voogt. ‘Our most sold is a watering sensor that measures soil moisture.’ It is not without reason that these sensors more or less ‘sell themselves’: ‘Roughly 90 percent of plant failure is due to either too much or not enough water.’ In order to properly measure the soil moisture, it has to be measured at the depth of the roots. And because tree roots go deeper into the ground than, for example, roots of perennials, the sensors are available in different lengths.

One of the other available sensors measures soil moisture, temperature and light. ‘Some of them have been incorporated into the Climate Cube on Osdorpplein in Amsterdam,’ says Voogt. The cube is a “green-blue spot” where, among other things, the effects of plants on urban heat stress are investigated. The ConnectedGreen sensors, both in the green cube and in a piece of “gray” a little further away, visualize the temperature trend in both places, and provide insights the difference between green and gray.

A frequently asked question, Voogt notes in response to this story, is how such sensors can be invisibly built into public spaces, such as busy shopping streets. Can a passer-by not just pick them from the ground? Not according to Voogt: ‘Sensors like this one are easy to conceal, for example under drainage caps or even mulch. These elements are often used around urban plants anyway. Built-in between the stones, the sensors are safely disguised.’

Traffic light

But it is not necessarily only about the sensors, Voogt emphasizes, while he opens the ConnectedGreen web app on the screen behind him: this is what it is all about. The dashboard looks simple at first glance. One thing stands out: the fiery red background. ‘The background color is like a kind of traffic light linked to the worst performing project,’ Voogt explains. ‘Green stands for good, yellow for dry or wet, red for too dry or too wet. This gives you an immediate visual overview of the situation.’ The dashboard therefore already provides an interpretation of the measurements. Voogt: ‘The sensors are of course important and have to function properly, but this is ultimately what it’s all about.’ The start screen shows a to-do list of all projects/sensors that are operating at a municipality, landscaping company or sometimes even private gardens. ‘When something is wrong with one of those projects, the system generates an alarm or task. If a plant needs water (read: if a plant is too dry), the task will turn red.’ The traffic light will only turn green again when the sensor measures that the plant has had enough water.

How do you determine whether something is too wet or too dry? ‘That’s the black magic of ConnectedGreen,’ Voogt jokes. ‘The app uses, among other things, horticultural knowledge and insights.’ ConnectedGreen is using the digital data in the databases of Van den Berk nurseries and Griffioen Perennials. ‘The specific needs of the 2,400 most used perennials and trees, such as water and light requirements, frost sensitivity, etc., are all in the system,’ says Voogt. ‘Based on the combination of the plant and the soil type in which the sensor is placed, the monitoring thresholds are determined – what is” good “(green) and what is” bad “(red).’

More calibrations mean better measurements

The choice of soil types is one of the key features of ConnectedGreen. Recently, a series of new, commonly used types have been added to the system. Voogt: ‘Selecting the right soil calibration is very important for the accuracy of the measurements. Every soil type is different. One is much more porous than the other, which means for example that it retains water in a completely different way. Sand has very wide pores and can therefore provide moisture to a plant starting from a moisture value of around 3 to 4 percent. That is why the “traffic light” is green when the water content is between four and eight percent.’ If you look at clay, which has much smaller pores than sand, the values are completely different. Above ten percent, sand becomes too wet, and you want to avoid that too. Too much water is at the expense of the oxygen content in the soil. And if roots cannot breathe, they will start rotting. ‘Especially in winter, we see that plants and trees are often too wet for a long time,’ adds Voogt. ‘That is why it is important to keep monitoring all year.’

The perfect moisture level for each soil type was determined based on analyses conducted by ConnectedGreen in collaboration with Eurofins Agro and sensor supplier Sensoterra. Voogt: “We took a sample of several kilos from every soil type. Using a special process, we then determined per soil type how the measured sensor values relate to the soil moisture present in the various samples. In this way we know what the water percentage is from dry to wet soil and what the sensor indicates.’

Project “Spoorzone” in the municipality of Tilburg. ConnectedGreen sensors monitor the trees and plants.

Calibration is essential

“Just ‘calibrating’ all the eleven types of soil we have available in our app, has taken sixty-six weeks of lab work,” explains Voogt. But it is worth it, he emphasizes. “If you, as a sensor supplier, don’t do that, the measurements won’t tell you anything.” That is no exaggeration, explains Voogt. “We see from many suppliers that their sensor has no calibration or only supports two or three soil types. But in Landscaping, there is much more than just sandy soil, loam and clay.”

Eleven calibrated soil types are quite a number. Yet the exact soil in which the sensor will be placed might differ slightly from the chosen soil type in ConnectedGreen. In that case, users can easily fine-tune the percentages manually. “Suppose the sensor is set to 8 percent for tree soil and indicates that the soil is dry. But when you feel the ground, you notice that it is not. Then you can fine-tune it manually in the system. “That option is essential, Voogt emphasizes. “After all, not all tree soil is the same. And putting a thousand different soil types in the system is of course also not an option. So, you can adjust manually based on observation. “


The API module is also new, says Voogt. “We see that municipalities that are using other computer systems attach great importance to linking those systems. Cities often have a smart city-like asset management environment, in which assets from different disciplines are managed. Integrate these with ConnectedGreen gives the municipality an opportunity to view sensor information in their tree management software platform in real time. “

“If a municipality has installed a number of sensors and a landscaping company has also installed a number of sensors in that municipality, then both parties can view the data of the combined sensors on their own ConnectedGreen dashboard (with the same login).” However, this is only possible if the sensor suppliers cooperate, Voogt adds. “If a sensor supplier is not willing to integrate their sensor in the ConnectedGreen platform, separate logins for each sensor brand/type are necessary. From a customer perspective, this is not desirable.”

ConnectedGreen at the Green Sector Trade Fair in Hardenberg

Hardware independent

That is inconvenient and unnecessary, says Voogt. “That’s one of the reasons we want to be hardware independent. If additional sensors, sensor types or suppliers are available, we are happy to add them to the system. That way, we will follow the hardware developments and enrich our platform over time. “In practice, some sensor suppliers are still somewhat reluctant. A shame, because the more sensors are integrated in the ConnectedGreen platform, the more the focus can be on what to do with the data. “We actually see te sensor hardware as a ‘hygiene factor’. It must just do its job – really well. For example, it must be able to stand outside in all kinds of weather, sometimes also be buried – and it should not corrode. The sensor tips have to be just as new after two years in the field; otherwise the quality of the measurements will deteriorate. “

It should also not be necessary to replace the batteries every six months or every year, especially in remote locations. All this will cost extra manpower, work and time, and this is just what ConnectedGreen wants to prevent with the platform.

It is not easy to build this kind of hardware, Voogt admits. And sometimes a sensor fails: “In such cases, of course we replace it immediately, but still, it can be annoying.” You cannot escape those start-up problems, according to Voogt. “A new technology is never completely flawless.” The most sold sensors from ConnectedGreen are getting better every year. “The customer doesn’t see that, but new elements are added to the sensors every year. This spring, for example, there will be an update for the antenna, the battery and the control software (the firmware). “Those adjustments were made based on the results of the predecessors, which have been in the field for more than two years. “The updates are based on experiences,” Voogt concludes. “This makes these sensors even better, and so do the measurements.”

The Golden Watering Can for the best solution for climate adaptation

The fact that ConnectedGreen is doing well was also evident last year when René Voogt took home our Golden Watering Can for the Best Product at the Climate Trade Fair. This competition was created in 2019 to find the best practical solutions against the effects of climate change.

The members of the professional jury, including Egbert Roozen, director of the VHG, Ben van Ooijen, director and owner of the Gardens of Appeltern and TV gardener Lodewijk Hoekstra, founder of NL Greenlabel, were impressed by the way how ConnectedGreen makes smart and modern techniques easily available for landscapers and governments.

Egbert Roozen: “Smart technology is entering the landscaping industry. Robotic mowers are increasingly being used and more and more techniques with app and home automation are now on the market. ConnectedGreen provides such a smart solution. Sensors in the garden monitor the watering; as a result, fewer project visits and less money are required. As far as I am concerned, we will be connecting green and smart technology even more in the future.

Ben van Ooijen: “It is an already existing system that has already proven to be right. Insight into the water requirement and improvement of the growing place to improve watering are matters that directly lead to savings, on water, but also on time. Garden owners, but also many landscapers and park managers have no idea what their plants actually need.”

Lodewijk Hoekstra: “What really appeals to me is the way in which ConnectedGreen provides simple insight into the condition of the soil using modern techniques. This results in more adequate management, which means that, among other things, water and energy are saved and the professional can better respond to issues such as climate change. “

Source: Stad+Groen https://www.stad-en-groen.nl/article/32374/koppelen-beheren-kalibreren-de-nieuwste-stappen-van-data-driven-connected-green

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