This study was sponsored by the Panamerican University Guadalajara campus. We thank the mechatronic engineering students for contributing to the experiment.

The protocol follows the guidelines of the Panamerican University ethics committee. The experiment was conducted with a total of 30 students, between 18 and 20 years old; eight students were female and 22 were male, and they all attended the Panamerican University in Guadalajara, Mexico (the second largest city in Mexico). All participants completed the informed consent process and provided written permission for photos to be taken and published during data collection. The only requirement was that the students needed to have a smart phone, which was no problem. Therefore, there was no exclusion criteria for the experiment.
1. VR system setup and calibration
NOTE: This step takes ~10 min.
<ol>
	<li>Ensure the system includes all the components: an Android phone with operating system version 10 or higher, VR box glasses, and a wooden base with a calibration image (Figure 1) (see Table of Materials).</li>
	<li>Open the MRE application on the cell phone and load the Unity, AR Foundation, Google Cardboard, and ManoMotion services25,26,27,28. The MRE application has been developed by ourselves; it was developed for Android and it is not public.</li>
	<li>Insert the cell phone into the VR glasses and put on the glasses.</li>
	<li>Visually locate the center of the base of the MRE prototype (the blue square in Figure 1).</li>
	<li>When the simulation appears, raise an outstretched hand to place it in the center of the view. 
	NOTE: From this moment, the users can make hand gestures to interact with the simulated environment.</li>
</ol>
2. User preparation
NOTE: This step takes ~5 min.
<ol>
	<li>Without VR glasses, open the MRE application, as shown in Figure 2.</li>
	<li>Ensure that the application starts in user mode so it is only necessary to log in.</li>
	<li>Select the scenario that the user wants to perform. There are two scenarios: electronic components and physics.</li>
	<li>Press Play; the user will have 30 s to put on the VR glasses.</li>
</ol>
3. Execution of scenarios
NOTE: This step takes ~15 min.
<ol>
	<li>Scenario 1: electronic components
	<ol>
		<li>Locate the areas to position components, by means of red, green, and blue colors. This delimits the six interaction zones of this scene: three zones to take the virtual electronics components and three zones to drop the components, as shown in Figure 3.</li>
		<li>Take the component and position it in the right place. The right place depends on the component and what is seen in theory; for example, in theory, it is explained how to place a heat sink, and in MRE said placement is practiced.</li>
		<li>Continue until all components are in place.</li>
	</ol>
	</li>
	<li>Scenario 2: physics
	<ol>
		<li>Locate the two cars involved in the scenario (Figure 4).</li>
		<li>Select the speed of each car.</li>
		<li>Visualize the graphs after the collision.</li>
	</ol>
	</li>
</ol>
4. Administration view
<ol>
	<li>On the main screen, press MRE modes (see Figure 2) and select the administrator option.</li>
	<li>Log in to verify if the account has permission to access as admin. 
	&#8203;NOTE: It becomes possible to view the list of students and the grades obtained in each scenario.</li>
</ol>
5. Student results
<ol>
	<li>Logging in as an administrator, click on the name of the desired student and view the table with the information of the grades of their scenarios.</li>
	<li>Click on a student&#39;s name and select download grades as CSV. This will display all the results in a comma separated file.</li>
</ol>

<ol>
	<li>The COVID-19 pandemic has changed education forever. This is how. World Economic Forum Available from: <a target="_blank" href="https://www.weforum.org/agenda/2020/04/coronavirus-education-gloabl-covid19-online-digital-learning/">https://www.weforum.org/agenda/2020/04/coronavirus-education-gloabl-covid19-online-digital-learning/</a> (2020)</li><li>How does virtual learning impact students in higher education. Brown Center Chalkboard Available from: <a target="_blank" href="https://www.brookings.edu/blog/brown-center-chalkboard/2021/08/13/how-does-virtual-learning-impact-students-in-hegher-education/">https://www.brookings.edu/blog/brown-center-chalkboard/2021/08/13/how-does-virtual-learning-impact-students-in-hegher-education/</a> (2021)</li><li>Loukatos, D., Androulidakis, N., Arvanitis, K. G., Peppas, K. P., Chondrogiannis, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+open+tools+to+transform+retired+equipment+into+powerful+engineering+education+instruments:+a+smart+Agri-IoT+control+example.">Using open tools to transform retired equipment into powerful engineering education instruments: a smart Agri-IoT control example.</a> Electronics. 11, 855 (2022).</li><li>Garlinska, M., Osial, M., Proniewska, K., Pregowska, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+influence+of+emerging+technologies+on+distance+education.">The influence of emerging technologies on distance education.</a> Electronics. 12 (7), 1550 (2023).</li><li>Parmaxi, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Virtual+reality+in+language+learning:+A+systematic+review+and+implications+for+research+and+practice.">Virtual reality in language learning: A systematic review and implications for research and practice.</a> Interactive Learning Environments. 31, 172-184 (2023).</li><li>Milgram, P., Kishino, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+taxonomy+of+mixed+reality+visual+displays.">A taxonomy of mixed reality visual displays.</a> IEICE Transactions on Information and Systems. 77 (12), 1321-1329 (1994).</li><li>Zaghloul, M. A. S., Hassan, A., Dallal, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Teaching+and+managing+remote+lab-based+courses.">Teaching and managing remote lab-based courses.</a> ASEE Annual Conference and Exposition, Conference Proceedings. , (2021).</li><li>Maas, M. J., Hughes, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Virtual,+augmented+and+mixed+reality+in+K-12+education:+A+review+of+the+literature.">Virtual, augmented and mixed reality in K-12 education: A review of the literature.</a> Technology, Pedagogy and Education. 20 (2), 231-249 (2020).</li><li>Noah, N., Das, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exploring+evolution+of+augmented+and+virtual+reality+education+space+in+2020+through+systematic+literature+review.">Exploring evolution of augmented and virtual reality education space in 2020 through systematic literature review.</a> Computer Animation and Virtual Worlds. 32 (3-4), e2020 (2021).</li><li>Gerup, J., Soerensen, C. B., Dieckmann, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Augmented+reality+and+mixed+reality+for+healthcare+education+beyond+surgery:+an+integrative+review.">Augmented reality and mixed reality for healthcare education beyond surgery: an integrative review.</a> International Journal of Medical Education. 11, 1-18 (2020).</li><li>Sinou, N., Sinou, N., Filippou, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Virtual+reality+and+augmented+reality+in+anatomy+education+during+COVID-19+pandemic.">Virtual reality and augmented reality in anatomy education during COVID-19 pandemic.</a> Cureus. 15 (2), (2023).</li><li>Soliman, M., Pesyridis, A., Dalaymani-Zad, D., Gronfula, M., Kourmpetis, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+application+of+virtual+reality+in+engineering+education.">The application of virtual reality in engineering education.</a> Applied Sciences. 11 (6), 2879 (2021).</li><li>Rojas-S&#225;nchez, M. A., Palos-S&#225;nchez, P. R., Folgado-Fern&#225;ndez, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Systematic+literature+review+and+bibliometric+analysis+on+virtual+reality+and+education.">Systematic literature review and bibliometric analysis on virtual reality and education.</a> Education and Information Technologies. 28, 155-192 (2023).</li><li>Brown, K. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+large-scale,+multiplayer+virtual+reality+deployment:+a+novel+approach+to+distance+education+in+human+anatomy.">A large-scale, multiplayer virtual reality deployment: a novel approach to distance education in human anatomy.</a> Medical Science Educator. , 1-13 (2023).</li><li>Birt, J., Stromberga, Z., Cowling, M., Moro, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mobile+mixed+reality+for+experiential+learning+and+simulation+in+medical+and+health+sciences+education.">Mobile mixed reality for experiential learning and simulation in medical and health sciences education.</a> Informatics. 9 (2), 31 (2018).</li><li>Tang, Y. M., Au, K. M., Lau, H. C. W., Ho, G. T. S., Wu, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluating+the+effectiveness+of+learning+design+with+mixed+reality+(MR)+in+higher+education.">Evaluating the effectiveness of learning design with mixed reality (MR) in higher education.</a> Virtual Reality. 24 (4), 797-807 (2020).</li><li>Halabi, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immersive+virtual+reality+to+enforce+teaching+in+engineering+education.">Immersive virtual reality to enforce teaching in engineering education.</a> Multimedia Tools and Applications. 79 (3-4), 2987-3004 (2020).</li><li>Borish, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Undergraduate+student+experiences+in+remote+lab+courses+during+the+COVID-19+pandemic.">Undergraduate student experiences in remote lab courses during the COVID-19 pandemic.</a> Physical Review Physics Education Research. 18 (2), 020105 (2022).</li><li>Trentsios, P., Wolf, M., Frerich, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Remote+Lab+meets+Virtual+Reality-Enabling+immersive+access+to+high+tech+laboratories+from+afar.">Remote Lab meets Virtual Reality-Enabling immersive access to high tech laboratories from afar.</a> Procedia Manufacturing. 43, 25-31 (2020).</li><li>Jona, K., Roque, R., Skolnik, J., Uttal, D., Rapp, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Are+remote+labs+worth+the+cost?+Insights+from+a+study+of+student+perceptions+of+remote+labs.">Are remote labs worth the cost? Insights from a study of student perceptions of remote labs.</a> International Journal of Online Engineering. 7 (2), 48-53 (2011).</li><li>Lowe, D., De La Villefromoy, M., Jona, K., Yeoh, L. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Remote+laboratories:+Uncovering+the+true+costs.">Remote laboratories: Uncovering the true costs.</a> 2012 9th International Conference on Remote Engineering and Virtual Instrumentation. IEEE. , 1-6 (2012).</li><li>Miles, D. T., Wells, W. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lab-in-a-box:+A+guide+for+remote+laboratory+instruction+in+an+instrumental+analysis+course.">Lab-in-a-box: A guide for remote laboratory instruction in an instrumental analysis course.</a> Journal of Chemical Education. 97 (9), 2971-2975 (2020).</li><li>Loukatos, D., Zoulias, E., Chondrogiannis, E., Arvanitis, K. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+mixed+reality+approach+enriching+the+agricultural+engineering+education+paradigm,+against+the+COVID19+Constraints.">A mixed reality approach enriching the agricultural engineering education paradigm, against the COVID19 Constraints.</a> 2021 IEEE Global Engineering Education Conference (EDUCON). IEEE. , 1587-1592 (2021).</li><li>Guerrero-Osuna, H. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Implementation+of+a+MEIoT+weather+station+with+exogenous+disturbance+input.">Implementation of a MEIoT weather station with exogenous disturbance input.</a> Sensors. 21 (5), 1653 (2021).</li><li>. Unity Technologies Available from: <a target="_blank" href="https://unity.com/">https://unity.com/</a> (2023)</li><li>About AR Foundation. Unity Technologies Available from: <a target="_blank" href="https://docs.unity3d.com/Packages/com.unity.xr.arfoundation@4.1/manual/index.html">https://docs.unity3d.com/Packages/com.unity.xr.arfoundation@4.1/manual/index.html</a> (2020)</li><li>. Manomotion Available from: <a target="_blank" href="https://www.manomotion.com/">https://www.manomotion.com/</a> (2022)</li><li>Create immersive VR experiences. Alphabet Inc Available from: <a target="_blank" href="https://developers.google.com/cardboard">https://developers.google.com/cardboard</a> (2021)</li><li>Demand for online education is growing. Are providers ready. McKinsey &amp; Company Available from: <a target="_blank" href="https://www.mckinsey.com/industries/education/our-insights/demand-for-online-education-is-growing-are-providers-ready">https://www.mckinsey.com/industries/education/our-insights/demand-for-online-education-is-growing-are-providers-ready</a> (2022)</li><li>Vergara, D., Fern&#225;ndez-Arias, P., Extremera, J., D&#225;vila, L. P., Rubio, M. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Educational+trends+post+COVID-19+in+engineering:+Virtual+laboratories.">Educational trends post COVID-19 in engineering: Virtual laboratories.</a> Materials Today: Proceedings. 49, 155-160 (2022).</li><li>Wu, B., Yu, X., Gu, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effectiveness+of+immersive+virtual+reality+using+head-mounted+displays+on+learning+performance:+A+meta-analysis.">Effectiveness of immersive virtual reality using head-mounted displays on learning performance: A meta-analysis.</a> British Journal of Educational Technology. 51 (6), 1991-2005 (2020).</li><li>Makarova, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+virtual+reality+lab+for+automotive+service+specialists:+a+knowledge+transfer+system+in+the+digital+age.">A virtual reality lab for automotive service specialists: a knowledge transfer system in the digital age.</a> Information. 14 (3), 163 (2023).</li><li>Cho, Y., Park, K. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Designing+immersive+virtual+reality+simulation+for+environmental+science+education.">Designing immersive virtual reality simulation for environmental science education.</a> Electronics. 12 (2), 315 (2023).</li><li>Burov, O. Y., Pinchuk, O. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+meta-analysis+of+the+most+influential+factors+of+the+virtual+reality+in+education+for+the+health+and+efficiency+of+students'+activity.">A meta-analysis of the most influential factors of the virtual reality in education for the health and efficiency of students' activity.</a> Educational Technology Quarterly. 2023, 58-68 (2023).</li><li>Loetscher, T., Jurkovic, N. S., Michalski, S. C., Billinghurst, M., Lee, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Online+platforms+for+remote+immersive+Virtual+Reality+testing:+an+emerging+tool+for+experimental+behavioral+research.">Online platforms for remote immersive Virtual Reality testing: an emerging tool for experimental behavioral research.</a> Multimodal Technologies and Interaction. 7 (3), 32 (2023).</li></ol>

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

The MRE system allows different scenarios for students to learn about electronic components or physics topics. An important point is the possibility of the teacher providing feedback. In this way, the students can know what they did wrong and why. With the MRE system developed, an experiment was carried out with 30 students, where 10 students did not use MRE, 10 used MRE, and finally another 10 used MRE and received feedback from the teacher. At the end of the classes, a general knowledge test was given to all the studen...

Technology has always been present in the education sector; profound changes have occurred in the devices used to teach classes. However, face-to-face classes remain the preferred option for students and teachers. When the pandemic came, it changed all sectors, and education was no exception. In 2018, before the pandemic, only 35% of students who studied a degree reported having taken at least one class online; that is, 65% of students completed their studies in person1. As of April 2020, by government order (Mexican), all public and private schools were prohibited from teaching face-to-face classes; for this reason, 100% of the students had to take distance classes. Universities were the first to act, using tools for video calling, preparing classes, homework management, etc. This makes sense, since people of university age (between 18 and 25 years old) are people who have been in contact with technology since birth.
Some classes can be fully adapted virtually; however, laboratory practices are complex to perform remotely, and students do not have the necessary material, which is often expensive. The impact that online classes have on the quality of knowledge is unclear, and some studies show that online courses generally yield worse student performance than in-person coursework2. But one thing is certain, not carrying out laboratory practices that bring students closer to what they will experience in the industry will negatively affect their professional performance. Therefore, the importance of real-scale experiences becomes necessary in the current teaching of engineering3,4,5. For these reasons, new technologies are being used to mitigate these problems. Among them are virtual reality (VR), augmented reality (AR), and mixed reality (MR). It is important to mention that VR is a technology that allows the creation of a totally immersive digital environment, whileAR overlays virtual objects in the real-world environment. On the other hand, MR does not just use virtual objects, but also anchors these objects to the real world, making it possible to interact with them. Thus, MR is a combination of VR and AR6. On the other hand, some organizations have also made efforts to develop remote laboratories, where real equipment exists but can be controlled remotely7.
The term MR dates to 1994; however, in the last 5 years, it has taken on special importance, thanks to large companies that have focused their efforts on developing environments, such as the Metaverse6. MR can be applied in different areas; two of the most common are training and education. Training has been one of the great drivers of MR; it is very expensive for a company to stop a production line to train new employees, or in dangerous environments, and it isn&#39;t easy to carry out training in the field. Education is not far behind; although face-to-face classes have changed very little, there are great efforts to incorporate MR into classes8,9. For education, there are professional careers where it is necessary to carry out laboratory practices to have complete training. Many existing studies and research are in medicine, with VR, AR, and MR playing a key role. Multiple papers show how MR surpasses traditional teaching methods in surgical and medical subjects, where the practice is a clear advantage for developing students10,11,12,13,14.
However, there is not the same amount of research on engineering issues. Normally in engineering careers, a student has theory classes complemented by practices. In this way, there are studies on MR and VR showing the benefits in engineering pedagogy12. However, some of these studies focus on analyzing the complexity of the environment and the tools used8,15. Tang et al. devised a study where students from different areas and with different knowledge used MR to improve their understanding of geometric analysis and creativity16. In a subsequent test, people who took their classes using MR finished faster, making it clear that MR positively affects learning16. Moreover, Halabi showed the use of VR tools in engineering education. Although it is not MR, it shows tools that can be used for teaching. It makes a real case study to show that it is possible to introduce VR in engineering classes17.
On the other hand, remote laboratories (RLs) are technological tools composed of software and hardware that allow students to remotely carry out their practices as if they were in a traditional laboratory. RLs are generally accessed through the internet, and are normally used when students are required to autonomously put into practice what they have learned as many times as they require18. However, with the arrival of COVID-19, its use has been to replace traditional laboratories and to be able to carry out practices during online classes18. As mentioned above, an RL needs a physical space (traditional laboratory) and elements that allow it to be controlled remotely. With the arrival of VR, laboratories have been modeled virtually, and through physical mechanisms, the elements of the laboratory can be controlled19. However, having an RL is very expensive, impeding many schools especially in developing countries. Some studies mention that costs can vary between $50,000 and $100,00020,21.
Moreover, since the pandemic began, changes have had to be made quickly; in the case of RLs, attempts were made to send kits to the homes of each student to replace the traditional laboratories. However, there was a cost problem, as studies showed that each kit cost around $70018,22. Nevertheless, the studies used expensive and difficult-to-obtain components. The pandemic affected education worldwide, and not many people could spend thousands of dollars to automate a lab or buy a kit. Most studies consider face-to-face classes and complement them with MR. However, in recent years, classes have been online due to COVID-19, and only some works show the improvement of virtual classes using MR and affordable devices23,24.
The research that exists so far is mainly focused on medicine, with little information on engineering. However, without a doubt, we believe that the greatest contribution and difference is that our experiment was carried out for 6 months and was compared with subjects with the same characteristics who did not use virtual models, whereas most previous works carried out short experiments to compare single technologies or procedures; they did not apply them over several months. Therefore, this paper shows the difference in learning that can be made using MR in a university subject.
For this reason, this work shows the development and results of an MR system to help carry out laboratory practices in universities focused on electronic engineering. It is important to mention that special emphasis is placed on keeping the cost of the device low, making it accessible to the general population. Three groups use different teaching methods, and an exam is conducted on the class topics. In this way, it is possible to obtain results on understanding the topics in distance education using MR.
The project explained in this work is called mixed reality for education (MRE) and is proposed as a platform where students use VR glasses with a smartphone (i.e., no special VR glasses are used). A workspace is created where students can interact with virtual environments and real objects simply by using their own hands, due to the use of virtual and real objects, a mixed reality system. This workspace consists of a base with an image where all the virtual objects are displayed and interacted with. The environment created focuses on conducting laboratory practices to show electronic components and physics for engineering careers. It is important to highlight the need to provide feedback to students. For this reason, MRE incorporates a feedback system where an administrator (normally the teacher) can see what is being done to rate the activity. In this way, feedback can be given on the work done by the student. Finally, the scope of this work is to check if there are advantages in using MR in online classes.
To achieve this, the experiment was carried out with three groups of students. Each group consisted of 10 students (30 students in total). The first group did not use MRE, only taking theory (online classes) on the momentum conservation principle and electronic components. The second group used MRE without feedback, and the third group used MRE with feedback from a teacher. It is important to mention that all students have the same school level; they are university students in the same semester and with the same career, studying mechatronics engineering. The experiment was applied in a single course called Introduction to Physics and Electronics, in the second semester of the degree; that is, the students had been in university for less than 1 year. Therefore, the topics covered in the class can be considered basic from an engineering point of view. The experiment was carried out on 30 students, as this was the number of students who enrolled in the class where the experiment was authorized. The selected class (Introduction to Physics and Electronics) had theory and laboratory practices, but due to the pandemic, only theory classes were being taught. The students were separated into three groups to see the impact that the practices have on general learning and if MR classes could be a substitute for face-to-face practices.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>MRE application for Andorid</td>
			<td></td>
			<td></td>
			<td>The application was developed for the experiment, it was made by us. It is NOT public, and there are no plans for publication.</td>
		</tr>
		<tr>
			<td>Non-slip fabric (20 x 20 cm)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Printing of our base image</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Self-adhesive paper (1 letter size sheet)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Virtual Reality Glasses</td>
			<td>Meta Quest 2</td>
			<td></td>
			<td>We use the Meta Quest 2, which is a virtual reality headset with two displays of 1832 x 1920 pixels per eye, with this headset you could play video games, or try simulators with a 360 view. Also, the headset has two controls, in which the virtual hands feel like your real ones and this is thanks to the hand-tracking technology. 
			https://www.meta.com/quest/products/quest-2/tech-specs/#tech-specs</td>
		</tr>
		<tr>
			<td>Wooden plate (20 x 20 cm)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

mixed reality for education (mre) implementation and results in online classes for engineering

The COVID-19 pandemic has changed many industries, empowering some sectors and causing many others to disappear. The education sector is not exempt from major changes; in some countries or cities, classes were taught 100% online for at least 1 year. However, some university careers need laboratory practices to complement learning, especially in engineering areas, and having only theoretical lessons online could affect their knowledge. For this reason, in this work, a mixed reality system called mixed reality for education (MRE) was developed to help students develop laboratory practices to complement online classes. An experiment was carried out with 30 students; 10 students did not use MRE, 10 used MRE, and 10 more used MRE with teacher feedback. With this, one can see the advantages of mixed reality in the education sector. The results show that using MRE helps to improve knowledge in engineering subjects; the students obtained qualifications with grades 10% to 20% better than those who did not use it. Above all, the results show the importance of feedback when using virtual reality systems.

This section shows the results obtained from the experiment. First, some details of how the experiment was carried out are explained, then the tests carried out on the students of the experiment are shown, and moreover, the results of the tests are presented. Finally, an analysis using one student of each group is described.
One of the biggest problems that the pandemic brought to engineering education was that it was not possible to carry out face-to-face laboratory practices, which has a dir...

Watch this Scientific Journal Video about Mixed Reality for Education MRE Implementation and Results in Online Classes for Engineering at JoVE.com

Mixed Reality for Education MRE Implementation and Results in Online Classes for Engineering

In this work, a mixed reality system called MRE was developed to help students develop laboratory practices complementing online classes. An experiment was carried out with 30 students; 10 students did not use MRE, 10 used MRE, and 10 more used MRE with teacher feedback.

Mixed Reality for Education (MRE) Implementation and Results in Online Classes for Engineering

The COVID-19 pandemic has changed many industries, empowering some sectors and causing many others to disappear. The education sector is not exempt from ...

mixed-reality-for-education-mre-implementation-results-online-classes

Research

JoVE Journal

Engineering

552 Views.  Panamerican University. In this work, a mixed reality system called MRE was developed to help students develop laboratory practices complementing online classes. An experiment was carried out with 30 students; 10 students did not use MRE, 10 used MRE, and 10 more used MRE with teacher feedback. 

Video: Mixed Reality for Education MRE Implementation and Results in Online Classes for Engineering

Implementation of a Reference Interferometer for Nanodetection

A thermally and mechanically stabilized fiber interferometer suited for examining ultra-high quality factor microcavities is fashioned. After assessing its free spectral range (FSR), the module is put in parallel with a fiber taper-microcavity system and then calibrated through isolating and eliminating random shifts in the laser frequency (i.e. laser jitter noise). To realize the taper-microcavity junction and to maximize the optical power that is transferred to the resonator, a single-mode optical fiber waveguide is pulled. Solutions containing polystyrene nanobeads are then prepared and flown to the microcavity in order to demonstrate the system&#8217;s ability to sense binding to the surface of the microcavity. Data is post-processed via adaptive curve fitting, which allows for high-resolution measurements of the quality factor as well as the plotting of time-dependent parameters, such as resonant wavelength and split frequency shifts. By carefully inspecting steps in the time-domain response and shifting in the frequency-domain response, this instrument can quantify discrete binding events.

A reference interferometer technique, which is designed to remove undesirable laser jitter noise for nanodetection, is utilized for probing an ultra-high quality factor microcavity. Instructions for assembly, setup, and data acquisition are provided, alongside the measurement process for specifying the cavity quality factor.

A thermally and mechanically stabilized fiber interferometer suited for examining ultra-high quality factor microcavities is fashioned. After assessing ...

Detection and Recovery of Palladium, Gold and Cobalt Metals from the Urban Mine Using Novel Sensors/Adsorbents Designated with Nanoscale Wagon-wheel-shaped Pores

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in industrialized countries. Here, the development of optical mesosensors/adsorbents (MSAs) for efficient recognition and selective recovery of Pd(II), Au(III), and Co(II) from urban mine was achieved. A simple, general method for preparing MSAs based on using high-order mesoporous monolithic scaffolds was described. Hierarchical cubic Ia3d wagon-wheel-shaped MSAs were fabricated by anchoring chelating agents (colorants) into three-dimensional pores and micrometric particle surfaces of the mesoporous monolithic scaffolds. Findings show, for the first time, evidence of controlled optical recognition of Pd(II), Au(III), and Co(II) ions and a highly selective system for recovery of Pd(II) ions (up to ~95%) in ores and industrial wastes. Furthermore, the controlled assessment processes described herein involve evaluation of intrinsic properties (e.g., visual signal change, long-term stability, adsorption efficiency, extraordinary sensitivity, selectivity, and reusability); thus, expensive, sophisticated instruments are not required. Results show evidence that MSAs will attract worldwide attention as a promising technological means of recovering and recycling palladium, gold and cobalt metals.

Because of the importance and extensive use of palladium, gold and cobalt metals in high-technology equipment, their recovery and recycling constitute an important industrial challenge. The metal recovery system described herein is a simple, low-cost means for the effective detection, removal, and recovery of these metals from the urban mine.

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in ...

A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens

Electrically assisted deformation (EAD) is increasingly being used to improve the formability of metals during processes such as sheet metal rolling and forging. Adoption of this technique is proceeding despite disagreement concerning the underlying mechanism responsible for EAD. The experimental procedure described herein enables a more explicit study compared to previous EAD research by removing thermal effects, which are responsible for disagreement in interpreting previous EAD results. Furthermore, as the procedure described here enables EAD observation in situ and in real time in a transmission electron microscope (TEM), it is superior to existing post-mortem methods that observe EAD effects post-test. Test samples consist of a single crystal copper (SCC) foil having a free-standing tensile test section of nanoscale thickness, fabricated using a combination of laser and ion beam milling. The SCC is mounted to an etched silicon base that provides mechanical support and electrical isolation while serving as a heat sink. Using this geometry, even at high current density (~3,500 A/mm2), the test section experiences a negligible temperature increase (&#60;0.02 &#176;C), thus eliminating Joule heating effects. Monitoring material deformation and identifying the corresponding changes to microstructures, e.g. dislocations, are accomplished by acquiring and analyzing a series of TEM images. Our sample preparation and in situ experiment procedures are robust and versatile as they can be readily utilized to test materials with different microstructures, e.g., single and polycrystalline copper.

A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens

Isolating electrical and thermal effects on electrically assisted deformation (EAD) is very difficult using macroscopic samples. Metallic sample micro- and nanostructures together with a custom test procedure have been developed to evaluate the impact of applied current on the formation without joule heating and evolution of dislocations on these samples.

Electrically assisted deformation (EAD) is increasingly being used to improve the formability of metals during processes such as sheet metal rolling and ...

Fabrication of Polymer Microspheres for Optical Resonator and Laser Applications

This paper describes three methods of preparing fluorescent microspheres comprising &#960;-conjugated or non-conjugated polymers: vapor diffusion, interface precipitation, and mini-emulsion. In all methods, well-defined, micrometer-sized spheres are obtained from a self-assembling process in solution. The vapor diffusion method can result in spheres with the highest sphericity and surface smoothness, yet the types of the polymers able to form these spheres are limited. On the other hand, in the mini-emulsion method, microspheres can be made from various types of polymers, even from highly crystalline polymers with coplanar, &#960;-conjugated backbones. The photoluminescent (PL) properties from single isolated microspheres are unusual: the PL is confined inside the spheres, propagates at the circumference of the spheres via the total internal reflection at the polymer/air interface, and self-interferes to show sharp and periodic resonant PL lines. These resonating modes are so-called "whispering gallery modes" (WGMs). This work demonstrates how to measure WGM PL from single isolated spheres using the micro-photoluminescence (&#181;-PL) technique. In this technique, a focused laser beam irradiates a single microsphere, and the luminescence is detected by a spectrometer. A micromanipulation technique is then used to connect the microspheres one by one and to demonstrate the intersphere PL propagation and color conversion from coupled microspheres upon excitation at the perimeter of one sphere and detection of PL from the other microsphere. These techniques, &#181;-PL and micromanipulation, are useful for experiments on micro-optic application using polymer materials.

Protocols for the synthesis of microspheres from polymers, the manipulation of microspheres, and micro-photoluminescence measurements are presented.

This paper describes three methods of preparing fluorescent microspheres comprising &#960;-conjugated or non-conjugated polymers: vapor diffusion, ...

Design and Implementation of a Bespoke Robotic Manipulator for Extra-corporeal Ultrasound

With the potential for high precision, dexterity, and repeatability, a self-tracked robotic system can be employed to assist the acquisition of real-time ultrasound. However, limited numbers of robots designed for extra-corporeal ultrasound have been successfully translated into clinical use. In this study, we aim to build a bespoke robotic manipulator for extra-corporeal ultrasound examination, which is lightweight and has a small footprint. The robot is formed by five specially shaped links and custom-made joint mechanisms for probe manipulation, to cover the necessary range of motion with redundant degrees of freedom to ensure the patient&#39;s safety. The mechanical safety is emphasized with a clutch mechanism, to limit the force applied to patients. As a result of the design, the total weight of the manipulator is less than 2 kg and the length of the manipulator is about 25 cm. The design has been implemented, and simulation, phantom, and volunteer studies have been performed, to validate the range of motion, the ability to make fine adjustments, mechanical reliability, and the safe operation of the clutch. This paper details the design and implementation of the bespoke robotic ultrasound manipulator, with the design and assembly methods illustrated. Testing results to demonstrate the design features and clinical experience of using the system are presented. It is concluded that the current proposed robotic manipulator meets the requirements as a bespoke system for extra-corporeal ultrasound examination and has great potential to be translated into clinical use.

This paper introduces the design and implementation of a bespoke robotic manipulator for extra-corporeal ultrasound examination. The system has five degrees of freedom with lightweight joints made by 3D printing and a mechanical clutch for safety management.

With the potential for high precision, dexterity, and repeatability, a self-tracked robotic system can be employed to assist the acquisition of real-time ...

O-cresol Concentration Online Measurement Based On Near Infrared Spectroscopy Via Partial Least Square Regression

Unlike macroscopic process variables, near-infrared spectroscopy provides process information at the molecular level and can significantly improve the prediction of the components in industrial processes. The ability to record spectra for solid and liquid samples without any pretreatment is advantageous and the method is widely used. However, the disadvantages of analyzing high-dimensional near-infrared spectral data include information redundancy and multicollinearity of the spectral data. Thus, we propose to use partial least squares regression method, which has traditionally been used to reduce the data dimensionality and eliminate the collinearity between the original features. We implement the method for predicting the o-cresol concentration during the production of polyphenylene ether. The proposed approach offers the following advantages over component regression prediction methods: 1) partial least squares regression solves the multicollinearity problem of the independent variables and effectively avoids overfitting, which occurs in a regression analysis due to the high correlation between the independent variables; 2) the use of the near-infrared spectra results in high accuracy because it is a non-destructive and non-polluting method to obtain information at microscopic and molecular scales.

The protocol describes a method of predicting o-cresol concentration during the production of polyphenylene ether using near-infrared spectroscopy and partial least squares regression. To describe the process more clearly and completely, an example of predicting the o-cresol concentration during the production of polyphenylene is used to clarify the steps.

Unlike macroscopic process variables, near-infrared spectroscopy provides process information at the molecular level and can significantly improve the ...

Implementation of a Nonlinear Microscope Based on Stimulated Raman Scattering

Stimulated Raman scattering (SRS) microscopy uses near-infrared excitation light; therefore, it shares many multi-photon microscopic imaging properties. SRS imaging modality can be obtained using commercial laser-scanning microscopes by equipping with a non-descanned forward detector with proper bandpass filters and lock-in amplifier (LIA) detection scheme. A schematic layout of a typical SRS microscope includes the following: two pulsed laser beams, (i.e., the pump and probe directed in a scanning microscope), which must be overlapped in both space and time at the image plane, then focused by a microscope objective into the sample through two scanning mirrors (SMs), which raster the focal spot across an x-y plane. After interaction with the sample, transmitted output pulses are collected by an upper objective and measured by a forward detection system inserted in an inverted microscope. Pump pulses are removed by a stack of optical filters, whereas the probe pulses that are the result of the SRS process occurring in the focal volume of the specimen are measured by a photodiode (PD). The readout of the PD is demodulated by the LIA to extract the modulation depth. A two-dimensional (2D) image is obtained by synchronizing the forward detection unit with the microscope scanning unit. In this paper, the implementation of an SRS microscope is described and successfully demonstrated, as well as the reporting of label-free images of polystyrene beads with diameters of 3 &#181;m. It is worth noting that SRS microscopes are not commercially available, so in order to take advantage of these characteristics, the homemade construction is the only option. Since SRS microscopy is becoming popular in many fields, it is believed that this careful description of the SRS microscope implementation can be very useful for the scientific community.

In this manuscript, the implementation of a stimulated Raman scattering (SRS) microscope, obtained by the integration of an SRS experimental set-up with a laser scanning microscope, is described. The SRS microscope is based on two femtosecond (fs) laser sources, a Ti-Sapphire (Ti:Sa) and synchronized optical parametric oscillator (OPO).

Stimulated Raman scattering (SRS) microscopy uses near-infrared excitation light; therefore, it shares many multi-photon microscopic imaging properties. ...

Evaluating Usability Aspects of a Mixed Reality Solution for Immersive Analytics in Industry 4.0 Scenarios

In medicine or industry, the analysis of high-dimensional data sets is increasingly required. However, available technical solutions are often complex to use. Therefore, new approaches like immersive analytics are welcome. Immersive analytics promise to experience high-dimensional data sets in a convenient manner for various user groups and data sets. Technically, virtual-reality devices are used to enable immersive analytics. In Industry 4.0, for example, scenarios like the identification of outliers or anomalies in high-dimensional data sets are pursued goals of immersive analytics. In this context, two important questions should be addressed for any developed technical solution on immersive analytics: First, is the technical solutions being helpful or not? Second, is the bodily experience of the technical solution positive or negative? The first question aims at the general feasibility of a technical solution, while the second one aims at the wearing comfort. Extant studies and protocols, which systematically address these questions are still rare. In this work, a study protocol is presented, which mainly investigates the usability for immersive analytics in Industry 4.0 scenarios. Specifically, the protocol is based on four pillars. First, it categorizes users based on previous experiences. Second, tasks are presented, which can be used to evaluate the feasibility of the technical solution. Third, measures are presented, which quantify the learning effect of a user. Fourth, a questionnaire&#160;evaluates the stress level when performing tasks. Based on these pillars, a technical setting was implemented that uses mixed reality smartglasses to apply the study protocol. The results of the conducted study show the applicability of the protocol on the one hand and the feasibility of immersive analytics in Industry 4.0 scenarios on the other. The presented protocol includes a discussion of discovered limitations.

This protocol delineates the technical setting of a developed mixed reality application that is used for immersive analytics. Based on this, measures are presented, which were used in a study to gain insights into usability aspects of the developed technical solution.

In medicine or industry, the analysis of high-dimensional data sets is increasingly required. However, available technical solutions are often complex to ...

A Versatile Kit Based on Digital Microfluidics Droplet Actuation for Science Education

This paper describes an educational kit based on digital microfluidics. A protocol for luminol-based chemiluminescence experiment is reported as a specific example. It also has fluorescent imaging capability and closed humidified enclosure based on an ultrasonic atomizer to prevent evaporation. The kit can be assembled within a short period of time and with minimal training in electronics and soldering. The kit allows both undergraduate/graduate students and enthusiasts to obtain hands-on experience in microfluidics in an intuitive way and be trained to gain familiarity with digital microfluidics.

We describe an educational kit that allows users to execute multiple experiments and gain hands-on experience on digital microfluidics.

This paper describes an educational kit based on digital microfluidics. A protocol for luminol-based chemiluminescence experiment is reported as a ...

Interactive and Visualized Online Experimentation System for Engineering Education and Research

Experimentation is crucial in engineering education. This work explores visualized experiments in online laboratories for teaching and learning and also research. Interactive and visualizing features, including theory-guided algorithm implementation, web-based algorithm design, customizable monitoring interface, and three-dimensional (3-D) virtual test rigs are discussed. To illustrate the features and functionalities of the proposed laboratories, three examples, including the first-order system exploration using a circuit-based system with electrical elements, web-based control algorithm design for virtual and remote experimentation, are provided. Using user-designed control algorithms, not only can simulations be conducted, but real-time experiments can also be conducted once the designed control algorithms have been compiled into executable control algorithms. The proposed online laboratory also provides a customizable monitoring interface, with which users can customize their user interface using provided widgets such as the textbox, chart, 3-D, and camera widget. Teachers can use the system for online demonstration in the classroom, students for after-class experimentation, and researchers to verify control strategies.

This work describes an online experimentation system that provides visualized experiments, including the visualization of theories, concepts, and formulas, visualizing the experimental process with three-dimensional (3-D) virtual test rigs, and visualizing the control and monitoring system using widgets such as charts and cameras.

Experimentation is crucial in engineering education. This work explores visualized experiments in online laboratories for teaching and learning and also ...