HSBI students develop a dartboard that guarantees a bullseye
Author: Ulrike Heitholt
In a work-related project, students on the work-integrated Bachelor’s degree course in Mechatronics/Automation at the Gütersloh campus of Bielefeld University of Applied Sciences and Arts (HSBI) have developed a dartboard that moves by itself so that a dart thrown at it always hits the bullseye. This is made possible by a sophisticated combination of high-resolution cameras, dynamic and precise drives, exact image processing, and programming. Numerous cooperating companies were involved in the project as sponsors – including, first and foremost, Beckhoff Automation.

Even the slightest wobble can throw a dart off-course. “Not a problem,” says Felix Lütkebohle. He’s right – because the dart hits the bullseye after all. But how? The dartboard itself has moved, shifting within a split second to ensure the dart lands exactly in its center. Felix is delighted: “It’s all thanks to mechatronics!”
Mechatronics/Automation also happens to be the name of the Bachelor’s degree course that Felix completed at the Gütersloh campus of Bielefeld University of Applied Sciences and Arts (HSBI). Over the course of seven semesters, students learn to combine knowledge from mechanical engineering, electrical engineering, and computer science, and to develop sophisticated technical systems. This course's special feature is that it is work-integrated, with students alternating between academic terms at the university and work terms at a cooperating company where they are also employed. Felix is employed at Beckhoff Automation, a global specialist in automation technology based in Verl.
Work-integrated studies – seamlessly integrating theory and practice
“Integrating theory and practice is very important to us in both phases of the work-integrated study program,” explains Prof. Dr.-Ing. Thomas Freund, who teaches electrical engineering and automation in the Faculty of Engineering and Mathematics at HSBI. Students are always working on practical projects during their time at the university. The most challenging is the compulsory mechatronics project at the end of the course, which takes place during the last two semesters. The bullseye project is one of these. Felix looks at the dartboard and describes it as “a real challenge”. The project requires various technologies, such as drive technology and image processing, to be combined and perfectly coordinated. “When will we ever get the chance to work on an amazing project like this again?” asks Felix, who took on the challenge together with a group of his fellow students.

However, it is only the subject matter of the bullseye project that makes it different from tasks with comparable requirements in an industry setting. “Our projects always revolve around simulating industrial working methods, so to speak,” explains Thomas Freund. This means working independently and as part of a team, using industrial components, and working through all stages of project management, from planning – including specifications, risk analysis, and time and budget planning – to execution, documentation, and acceptance measures such as CE markings and declarations of conformity.
Image processing, programming, project management, documentation – just like the real world of industry
The student team working on the bullseye project assembled itself quickly: Felix was joined by Louis-Pierre Detemble, Linus Bröker, and Jule Brede, all of whom were enthusiastic about the task. With the exception of Jule, who completed her work-integrated HSBI studies at Schüco International KG, all the students in the bullseye team are also Beckhoff staff – just like the members of the teams who came before them. Jule expressed a particular interest in the interplay between the different areas within the project: “They build on each other and shouldn’t be viewed as separate components. To implement proper image processing, for example, the mechanics have to be in place first.” Jule concentrated on the mechanical aspects, Louis-Pierre and Linus took care of programming, and Felix was responsible for image processing and project management. The team did not start from scratch, however: “Some projects, like the bullseye one, are so complex and comprehensive that several groups end up working on them over multiple semesters,” says Thomas Freund, explaining the approach.
The four students in this case were the third team to work on the bullseye project. “The preliminary groups had already done a great job and prepared an incredibly helpful project handover,” says project manager Felix. His team’s goal was “to increase the hit rate and make the system even faster.” This meant improving the speed by increments even smaller than seconds. Linus picks up a dart and demonstrates a throw: “According to the rules, the distance between the dartboard and the person throwing the dart must be 2.37 meters. From the time the dart is thrown, it takes only 140 to 150 milliseconds until it hits the target.” That’s not much time to calculate the trajectory and position the dartboard accordingly.

Beckhoff and other companies lend their support to the bullseye project
The students focused on image processing and were able to use newly developed industrial cameras with a higher recording rate so that more images could be taken to calculate the trajectory. “When we took over the project, the components were still prototypes,֨” says Felix. Thomas Freund is pleased about the new cameras: “We usually try to use advanced methods and the latest hardware in our projects.” However, he admits that none of this would be possible without sponsors. “It makes us all the more grateful for our cooperation partners’ willingness to provide us with the components we need.”
For Beckhoff, getting involved was a no-brainer; the company was happy to provide the mechatronic components. “We’re delighted to support our work-integrated students with their study projects. After all, Beckhoff benefits from employees who have received outstanding training,” explains Dr. Ursula Frank, who manages R&D collaborations at Beckhoff Automation. She adds: “Prototypes such as the image processing components used in this case undergo an additional practical test. We’re thrilled that we can use the findings from the study projects to optimize and further develop our own solutions.”
For Felix, the introduction of new cameras with a higher recording rate meant reprogramming the image processing: “The trajectory captured by the cameras in three dimensions is displayed as a ballistic curve in order to calculate the exact position at which the dart hits the target.” This must be achieved in half the flight time. Louis-Pierre adds: “In the remaining 70 milliseconds or so, the center of the dartboard must be brought – or, as we say, “driven” – to the calculated position. To ensure that this happens with the high level of dynamics and precision required, linear motors from Beckhoff were installed in the bullseye. “They don’t rotate like conventional rotary motors – instead, they push the objects being driven in a straight line,” explains Thomas Freund. Gravity also helps with the dartboard’s downward movement. But what about the upward movement? “We have installed a second auxiliary drive to make the upward movement even faster,” explains Jule, referring to another optimization.
All that’s left to cover the documentation. The students look slightly embarrassed, and finally project manager Felix admits with a laugh: “It’s not necessarily your favorite thing to do if what you’re really interested in is the technology.” Thomas Freund nods sympathetically: “But it’s also very important – and it’s indispensable, as it’s legally relevant.” This means that the team has, of course, fulfilled its documentation obligations too. “It works best when you document everything at the same time as you’re doing the practical work on the project,” states Jule. “You can’t leave everything until the end – if you do, you’ll end up getting mixed up or running out of time.” Thomas Freund was more than satisfied with the result. And the documentation will be extremely useful for the next team, because the bullseye project is still not finished after its third outing. Felix throws a dart. “There’s always room for improvement.”
Who supports the bullseye project?
The bullseye study project is underway thanks to the support of the following sponsors:
akki Werbetechnik, Beckhoff Automation, Carbon-Werke Weißgerber, Dreckshage, Franke, Harting, igus, Mädler, Metallbau Helmut Blomberg, Rittal, Schüco