The Device Chronicle interviews Alwin Meenderwink, Software Architect at smart agriculture OEM Rometron, with its innovative product Weed-IT.
IoT connectivity, embedded software, and algorithms redefine agricultural processes, leading to significant outcomes in productivity and production. A great example is Weed-IT from Rometron, which promises a 90% reduction in pesticide use in the extermination of weeds in shallow, out-of-crop fields.
Developed by Rometron, Weed-IT combines a detection system and a spraying system. Alwin Meenderwink leads the development of the current and new software solutions for Rometron. Alwin starts by describing the Weed-IT sensor: It is a sensor that detects active chlorophyll. There is an active light source which shines on the field. The plants give a little response as they start photosynthesis, and the sensor catches this response. The response gets multiplied by a hundred thousand times, and an infrared signal within 660 nanometers helps determine if it is active chlorophyll, which means fresh green plant material, and decides if a weed needs to receive herbicide spray droplets.
Background on technology
The technology behind Weed-IT was first developed 25 years ago during a research project at the University of Wageningen in the Netherlands. The original use case was for spraying weeds on pavements, and it was used this way for a few years. However, in 2005, new regulations forbade spraying pesticides on pavements. By then, the system had become widespread, iterated upwards of 15 times, and it found applications in agriculture. Alwin explains, “A student was doing an internship in Australia, and they were looking for a method to detect weeds in agriculture. In Australia, the agriculture methods differ from those in Europe because they use no-tillage. They keep the ground as quiet as possible because moisture is lost when tilling it. So, the no-tillage method is necessary in Australia's dry climate because you do the harvest, and after the harvest, the first thing that comes up is to weed. Everything that comes up is green, and you have to attack it. And if you do, then you can save almost 98% of the pesticide. The sensor technology is necessary in these agricultural conditions because the fields are vast, and you can achieve considerable savings.”
How Weed-IT works
Weed-IT’s prime function is to analyze and kill weeds after the harvest. The primary offering is getting weeds 90% reduced, so the system's return on investment is one to two years. The end customer buys a sensor and four PWM spray nozzles for every meter. Every sensor has spray nozzles, a console, a screen, and a power unit to manage the system voltage. Alwin explains, “There is a pulsating nozzle that works with frequencies up to 50 Hertz. So we can also keep the spray rate consistent. You can imagine when the spray boom is driving through a corner, the outside of the boom is traveling much faster than the nozzles on the inside. With the Pulse Width Modulating (PWM) technology, you can keep the rate consistent over the whole boom." The devices are produced in the Netherlands, and currently, there are an estimated 2,000 systems in the world. The company has distributors in Australia, North and South America, and South Africa. The distribution network is both retrofitting the technology to existing sprayer platforms and integrating new sprayers as an OEM solution.
Embedded design of Weed-IT
The WEED-IT team is also developing a dashboard portal called Dash; This includes an Advanced Controller and a new HMI screen for control by the operator. AWS is used for cloud services and application telemetry. The project was to create an online system to track system information and perform embedded software updates over the phone. “So, due to it taking four to eight hours of driving, especially in the wide Agricultural markets where WEED-IT is used to send a service technician to the devices, we decided to make the system remote. This means the system can be monitored remotely, and the farmer can also create maps of the chlorophyll detection levels. The Mender OTA update manager is used for online updates and remote updates. Alwin says, “So, if a new firmware version is needed, we can update it and send it to the machine where the Advanced Controller and the HMI screen are updated.” The Rometron team developed their own carrier board for both the HMI screen and the Advanced Controller. Yocto was used to make the board support package, and they are distributing the whole BSP and its applications. This update has the size of a couple of hundred megabytes because it contains the complete operation systems and applications. “And when hardware and software are stable at the end of next year, we can only deploy the applications self; Then an update will only have the size of a few megabytes."
Software management and dashboards
The Dash system will be introduced in the spring of 2025. The dashboard portal communicates with the Advanced Controller. The dashboard portal is designed for the distributor to monitor the systems and for the farmer to download their spray maps, biomass maps and other data from the system. The Dash portal communicates with the Mender OTA update manager using APIs. “So, all the firmware is put in Mender, and we can put a machine in our dashboard. The whole package is sent to the Advanced Controller, and he is doing the distribution of the separate software applications. It is a Linux platform with multiple applications running on it.”
The HMI screen is also Linux-based, with applications installed on it. And then all the sensors have their own operating systems. Alwin explains, “The sensors are very light, and all decisions are made by the sensor. So, that is why we have an extremely fast detection algorithm. There is no communication or heavy procession involved. We do not have any processors in between or inter-machine communication, so we can make real-time decisions. That is the reason a driver can drive up to 30 km an hour, also with systems up to 48 meters. Even at that speed, WEED-IT can detect weeds with a size of one-by-one centimeter.”
Next developments
In the future, Rometron may look to add Delta updates to compress the size of the artifact images over cellular connectivity. They also use Rollback in Mender to prevent device bricking and Mender’s State Machine and update modules to control the update flows carefully. Automatic retries on software updates are used after 24 hours.
The Rometron team also believes that although all configurations are tested in the field, uncertainties may still occur, and unexpected challenges must be faced.
Alwin remarks, “Although the software package to be deployed is tested at all known platforms and configurations, when you go to the customer in the field, all kinds of different unexpected things can happen. You must be prepared for this, and that is why we always want to update the system as smooth and seamless as possible
Besides this, Rometron is putting a lot of effort into (cyber)security. All communication must be secured with secured APIs, certificates, and encryption.