My name is Steven Wagner and we are here from the Technische Universität Darmstadt in Germany to present our lecture concept for mechanical engineering graduate studies with the myrio. As the title implies: We want to brew the perfect cup of coffee by using the myrio. While a scientific talk usually starts with a very fact driven motivation and structure, we want to start differently. Let us first give you an idea of what our lectures looks like from the student point of view.
Movie available at our website: www.htpd.tu-darmstadt.de This was a short run-through of the lecture showing you all the different phases of the lecture. Let me now discuss the lecturer s perspective in detail.
Within the master s degree program of mechanical engineering in Darmstadt, we see some major gaps of knowledge that students have to close. They have no real-world experience with sensors and sensor hardware. They are not educated in LabVIEW. If the students take classes in electronics, mostly it is just a theoretical discussion of the principle and most of the times, doesn t include any labs. So they do not have any hands-on experience understanding single components or even a complete measurement system. But the problem is: Today you will not find a modern industrial process or product without a significant amount of digital measurement technology in it. Just theoretical knowledge is not sufficient to develop or operate such systems. Hence they need a course that prepares them for these challenges by offering specific content and teaching the material very differently.
Hands on experience is needed to understand sensors and sensor principles. Once you used a sensor in a real-world application, you know how it works and you know the problems. Students need to know LabVIEW in conjunction with practical experience in the use of modern measurement electronics. When combining all of these, they can run through the complete product development processes and learn to build complete measurement systems. This means that they need to as Dave (Wilson) would say Do engineering. The questions we need to ask ourselves therefore are: But how can we put all of this into a one semester-long course? What structure would cover all these topics and how do we want to teach them?
Let s take a look at the different steps of a complete industrial product development process. You start with Ideas and concepts, followed by an initial hardware prototype. Based on the available hardware and the concept you designed, you start to develop the software and finish the project with product design. The idea of our course is to cover all these points by using a coffee maker as an example for all the steps of the process and the development as well as the exam. But this means using a real-world coffee maker
like the one shown here. Unfortunately this coffee maker doesn t easily work with a myrio. Therefore, in 2013, we started to transform a commercial coffee maker into an engineering test stand. Obviously it was not a version well suited for lectures as one might expect from an engineering department, but sufficient to get first experiences with our teaching concept. The initial feedback was great and students really liked the idea of using a real-world example known to everyone for the course and the labs. Since we only used the available sensors of the standard coffee maker so far, improving the concept meant developing a more advanced version. Starting with
the same machine but a lot more experience and an improved content structure we started building a new and improved test stand, which has a professional housing with easy but secure access to the core components. All these components are clearly visible, but It is now save to operate, since no student can accidentally touch any high voltage component. All sensors and actuators are easily accessible by the students via standardized connectors. Let s take a closer look the machine.
In the picture on the left you can see the different components like pump, heater, coffee spout and cup holder. Most of the sensors and actors are connected via a panel on the left side, which you can see in the middle. For security reasons the cup holder environment is equipped with different switches like a distance switch for detecting the presence of a cup, a pod-holder switch, which detects if the pod holder is closed or not and a level switch in the water tank to ensure sufficient water is in the tank. If we take a closer look
at the test stand, you can see the main components like tank, pump, heater, pod holder and the coffee cup itself. The pump and the heater can be controlled with a myrio which is decoupled from the high voltage circuit by relays. For the test stand control and operation, we installed thirteen sensors. One example is a thermocouple. Here the challenge is the amplification of the very low voltage signal. As another example we included a weight sensor including amplification. When it comes to communicating with actuators or sensors via digital bus protocols, we selected an I2C display as a relatively easy to implement component. All the sensors and actuators are fixed and connected in the test stand, but most of the read-out circuitry for signal preparation or amplification needs to be build by the students on their MXP breadboard. Therefore they use
their own laptops with LabVIEW student edition. Additionally we provide each student with a complete kit to take home. It includes a myrio, several sensors, LEDs, actuators, a multimeter, an MXP-board and everything necessary to build their own circuits like jump wires. The tool box also includes more components than needed for the lecture. We want to inspire the students to try out their own ideas at home and test the different abilities of the myrio in conjunction with some simple electronic components. How to use these tools with the coffee maker as an example is at the core of the lecture. Let me give you an overview of the lecture now.
The lecture consists of four different parts. First, we teach the students sensor principles to allow them to understand the physical context of the measurement system. We teach the application of different hardware options depending on the signal that should be acquired. Besides LabVIEW basics, one central objective of the class is to introduce the students to important and commonly used programming principles. You will see the details in a minute. And finally we use the student project at the end of each semester to combine the knowledge from the different parts into a complete product development and design process. But what are those parts in detail?
We teach the students about a variety of sensors and basic sensor principles, different hardware components and programming strategies as well as concepts to employ in the final project, which is also what the students will be graded on for the most part. Due to the limited amount of time during the semester, this content is just what they need to finish the final project. But if you take into account that these students are mechanical engineering students, they do not have any significant knowledge about most of these topics at the start of the semester. They have to learn a lot in a very short time and most of it will only be fully understood by the students when they put all the parts together in the final project. Given a normal semester,
we structured our lecture to allow 18 hours to teach the fundamental basic with less hands on at the beginning. The amount of hands-on work increases significant within the focus areas, where we schedule roughly 18 hours to teach sensor principles and advanced concepts like bus systems. The lecture concludes with the project, where they have 2 weeks to complete the project objectives in groups of 2 to 4 students. This project combined with an oral exam of 30 minutes are the bases for the final grading. Now, that you have an idea of the lecture structure and the content let me show you some examples of what our lectures look like
For example, we will start with a hardware setup where the students have to measure an unknown resistance using a four-wire sensing circuit. During the lecture itself, we give a brief explanation of the circuit and the basic ideas behind it. Subsequently, they will get a problem statement and start building the circuit based on the schematic and connect it to the myrio. Later on, they will program the software to measure and calculate the resistance of the potentiometer or a resistance temperature device. And since we are teaching measurement sciences, they also have to document the measurements and evaluate the results regarding accuracy and precision. With each exercise they are getting better and better at identifying sources of measurement errors and identifying the total amount of uncertainties as well as reducing the sources of these uncertainties. Due to the increasing complexity of the exercises as the semester progresses, the students also need to improvement the software components accordingly
As an example let me show you some code snippets from our students when working with the I2C display. Digital communication procedures are usually not as easy as they should be given that different components have different command sets. But as soon as you use basic programming structures, like QDSM in conjunction with the myrio I2C driver, the step needed to understand and implement such communication concepts becomes very small. Using LabVIEW s modular architecture via functional Sub-VIs, it is easy to implement different devices and configurations. All the hardware circuits and the LabVIEW Vis, the students develop, are modules that will later be put together into a complex measurement system aka our coffee maker. For example, the VI, that reads a NTC or a Pt100, needs to be as modular as needed to be later used in the different context of the coffee maker. Let me talk a little bit more about the project, especially from a teacher perspective
At the core of the final project is running through a complete product development process starting with the concepts and finishing with a nice user-friendly customer interface. They have to use the acquired knowledge from the lectures together with all the tools they build during the semester to work in teams on the coffee maker project. Together with a brief documentation of the design and development process, including log-file data from a successful test-run, the project source code represents a major part of the final grade. So, how do we determine a student s grade?
We look at the hardware design, the code structure and code quality as well as the final functionality. Herein an important part
is the graphical user interface and the implemented functionality, for an engineer running the test stand as well as for the customer, since the end-user interface is essential for a product s success and therefore part of the grade. Finally a product development process always concludes with a
documentation of the hard- and software in the system, the design, test results and system characteristics. Since this also marks the end of semester, let me close our presentation with a few words on what we learned so far and, more importantly, what the students learned
If we look back at where the students started, they are now well educated in the use of LabVIEW in conjunction with the myrio for measurement systems. They understand basic sensor principles as well as basic sensor electronics to develop simple measurement systems. They worked very independently in their groups to build a complete measurement system and gather a large amount of practical experience with the hardware and with LabVIEW while working with modern measurement electronics. Finally and most important they do engineering and they have fun. But, what did we
as teachers learned so far? Hands-on lectures are necessary instead of theoretical discussions of the underlying principles. Students always prefer learning by doing. But this concept needs a significant number teaching assistants. As we have 20 students per semester, we are at least one lecturer and three extremely motivated assistants. Nevertheless, we can only do as much as we can, so the students have repeat the labs between the lectures at home. To motivate them and ignite the interest it is important to give them different exercises as homework. As a conclusion of the last 2 years, let me just say this: It was really a lot of work, but also a lot of fun for us.
Concluding this presentation, I want take this opportunity to thank Marc Backmeyer for his limitless support to establish the LabVIEW Academy in Darmstadt with our course as the central part. I also thank our university for the financial support and thank you for your kind attention this morning.