Abstract
This work presents an educational freeware software that operates as a data logger and a large display to allow a satisfactory viewing of the numerical information, even by students far from the experiment, and therefore it is a tool designed to help experimentations and demonstrations based on Arduino boards in educational physics laboratories.
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1. Introduction
Educational strategies based on demonstrations and experimentations are widely used because of their relevance for the teaching-learning processes, and they have motivated several studies [1, 2]. Demonstrations include advantages such as the saving of expensive material resources, the following of hazard experiments without direct contact with them, and the theoretical explanation in real time with the events occurrence. However, the experimental activities where students perform their own practical tests are essential to provide them with skills for hands-on activities and usually compose a more motivational scenario.
In fact, both strategies may be complementary, where students are firstly familiarized with specific procedures and apparatus through the teacher's demonstrations, and later they perform their own experiments. This motivated the present work, which presents an educational software to help both educational strategies.
2. The software design
Figure 1 shows a system for the presented software operation, which also includes an Arduino board and sensors. The software, called DisplayBoard, has only two simple operational panels called yellow and blue. Figure 2 shows the yellow panel that shows the received data with large digits for demonstrations, and figure 3 shows the blue panel that works as a data logger.
Figure 1. The conceptual system.
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Figure 2. The yellow panel.
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Figure 3. The blue panel.
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Standard image High-resolution imageThe DisplayBoard starts its operation when the user sets the serial interface number and clicks on the Start Data Acquisition button in the blue panel. It was designed to simulate simple meter displays and therefore it accepts only real and integer numbers with up to with five digits in a range from −99 999 to 99 999, without text. It means that the user's program that runs on Arduino must only send numbers, one at a time, through the traditional Arduino command Serial.println.
2.1. The yellow panel
Figure 2 shows the yellow panel that works as a large numerical display whose digit height (h) is 8.5 cm in a computer screen with a diagonal length of 23° (58.3 cm) and resolution at 1920 × 1080 pixels.
This digit height represents a visual angle (θ) of 22 arcmin at a distance up to 13 m. This visual angle ensures a higher legibility [3] and the associated distance is realistic for usual classrooms or educational laboratories. Besides the digit height, the relation between the display background and the digit colours also influences the viewing. This relation is referred to as the contrast ratio, and the yellow background with navy foreground (digits) ensures a contrast ratio of 14.7:1 that is higher than the minimum recommended by international standards [4].
The parameters above numerically prove the yellow panel's efficiency, and therefore this section concludes that it has a real potential to help the demonstration of practical activities.
2.2. The blue panel
Figure 3 shows the blue panel that operates as a data logger system, which is useful for experiments that require the data recording for later processing and analysis, and therefore was designed to help students' experimentations rather than teachers' demonstrations.
The control options in the blue panel are intuitive and can allow their use even by people without previous training.
The blue panel has three smaller displays, whose functions are:
- 1.Display-A: It shows all the received data from the Arduino. Figure 4 shows that each line refers to specific data, and it includes the sequential data number, the time elapsed since the first data reception in seconds, and the data value.
- 2.Display-B: It shows the same information of the yellow panel display, but with a smaller size.
- 3.Display-C: It is a stopwatch whose operation starts automatically when the process is started.
This panel also has a box called 'Data Logger Control', which has four control buttons summarized as:
- 1.Start Data Acquisition and Reset All have intuitive functions.
- 2.Save Received Data: It saves all the data shown in the Display-A in a file type text, whose name and directory are defined by the user. Later, different softwares such as Matlab, Excel or Word can directly import this file.
- 3.Serial Communication: Here, the user must set the serial port number associated with the Arduino board, which is automatically fixed by the computer when both are connected through the USB. The user can verify it in the Windows system option 'devices and printers'.
Figure 4. The data line structure in the Display-A.
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The blue panel simplicity indicates its potential to serve even students without previous experience with data loggers.
3. A test system
There are several measurement systems that can demonstrate the DisplayBoard usage, such as the figure 5 system that demonstrates it through an analogue temperature sensor model LM35. This system is simple, inexpensive and it may be fun if the teacher covers the sensor with his fingers to cause a rapid temperature change.
Figure 5. System test with temperature measurement.
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Standard image High-resolution imageThere are simple ways to open the saved text data file and plot its graph with free of charge software. Figure 6 shows it through a short procedure in Python language.
Figure 6. Graph plotting with Python.
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Standard image High-resolution imageFigure 7 also shows the graph plotting, but using Octave that is a programming language similar to the traditional Matlab.
Figure 7. Graph plotting with Octave.
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4. Conclusion
This work presented a user-friendly freeware software that allows a satisfactory numerical data demonstration at distances of up to 13 meters and, besides, can operate as a data logger to help students' experiments.
Readers can download a free of charge software copy from the link (https://drive.google.com/file/d/1Gm9saG2Gkfw9YTsnkiZ-ITCJKZKDvYdf/view?usp=sharing) or by contacting the author.