 Well, so my name is Christian. Well, many people have problems with my surname here. My surname is Guajardo. So if you find a Spanish surname with J here, it sounds like more or less when you are sick, like, ah. So it's Guajardo. Well, I am a researcher from this university, but not in this campus. I'm a researcher in Bancontien campus. And it's pretty exciting time for me this time because it's the first time we do or we work, actually, with an open source project, actually, based on an open source project that is existing now. So well, I will show with you and share with you my experience and experience of my students with this project. So as you see here, it is building a wax printer. Well, actually, we took a 3D printer and we turned it into a wax printer. And for using it in the lab, I work in sensor technology laboratory and we fabricate prototypes of sensors and develop sensors. So mostly what we do is chemical analysis and this is the printer for fabricating this kind of devices for chemical analysis. So today I will talk about mostly two things. One, probably many of you don't know about chemical analysis, so I will give a short motivation for chemical analysis. The current technology that you may have seen in the market, the new technology that is not in the market that we are working in the research and how to build this technology. This technology is called paper-based microfluidics and mostly for fabricating these, we need wax printers, so that's why our project. And then why to build the wax printer? And then we go into some details of the projects that we did with our students. And then some final words regarding open source and our experience. So this is more or less what you can find now in the market. And chemical analysis normally was still now, but more in the past was done mostly in the labs. But from time, some years ago, these analysis, these tests have been moving from the lab to devices that you can buy in the pharmacy or that you can hold in your hand. For example, these three are the three most famous, probably. The first one is a urine test. The second is the pregnancy test and the third is a glucose sensor for patients with diabetes. So in this one, if you have a sample of urine, instead of sending to the lab to analyze, you just buy this strip, you put your sample of urine here and it will flow. And when it flows, it will change colors here. Each of these squares measures one component, let's say, of the urine. And depending on the intensity of the color, then you will know whether you have more or less of one of these components in urine. For example, albumin or glucose or protein or whatever. Another one that is probably most common is the pregnancy test. Here, the woman puts a sample in the pregnancy test and if it appears this bar here, then it means that she's pregnant. If it doesn't appear, it means that she's not. And it measures some proteins that are present in the body of the woman. This one, as I told you before, is for the patients with diabetes. This one is not as simple as these two because it requires an electronic component which delivers the resulting numbers, how much glucose you have in your blood. And the way it works is just to put a sample of blood here and it tells you how much blood you have in your blood. So these three kinds of devices are quite simple in general because the sample that you put in these devices either stays still, like in this case in the sensor, or moves only in one direction and the detection is pretty straightforward. You just put the sample there and immediately you measure the concentration of the analyte that you are interested in. These kinds of devices, they don't perform analyzes in several steps. They just do it in one step. So complex analytes that require, let's say, filtration or pre-processing before measurement, you cannot do it with them. So this is where the new technology comes. So in difference from this one with the previous, well, the name of this technology is called a paper-based microfluidics. Well, this technology allows you in difference with the previous one that the flow here is not linear or the liquid doesn't stay still in a single spot. You can direct the flow of liquid in your device to different stages where each stage of the device perform different steps in complete analysis or test of some sampling of some protein or molecule in your samples. So in this way, the sample can follow very intricate patterns to go from stage to stage. And the way to direct the liquid in these devices is by using channels. And these channels flow in paper in defined directions because these channels are made from a hydrophobic barrier. It means a barrier that doesn't let water or liquid go out. One very simple material for fabricating these barriers is wax because wax is hydrophobic and it won't let the liquid go out from the tracks that you define. So for example, in this case, the sample doesn't flow linearly. This one detects glucose in blood as well. And in difference with the previous one, this one is optic, it's not electronic. So you put the sample here in the middle. In the middle it has a lot of antibodies that agglutinate the red blood cells so you can somehow separate the plasma from the big bodies of the blood. And then the plasma goes to each of these ends of the device where it has a control signal and it has the signal of your measurement in triplicate, which is different from the previous one. The previous one, this electronic version only gives you one measurement, but this one gives you the measurement in triplicate so you can make sure the measurement is more accurate. And well, visually it can give you an estimate of the amount of glucose that you have in blood. But if you want something more quantitative, like with a specific number, the people couple these things with mobiles. Everyone nowadays, almost everyone has mobiles and you can analyze the intensity of the color by using applications on the mobile and that will give you a number of how much glucose you have in your body. This is more or less the kind of intricate patterns that the fluid can follow within the device. This device is printed in a sheet of paper, but this sheet of paper with these nine squares can be folded. So the sample comes and passes through each of these, well, following the arrows here. It passes through each of these different squares and in each of these different squares, they perform different stages of the process of analysis of the sample that you want to measure. This one also detects glucose and protein in urine. It's much more complex than the previous one. And this one also, it detects nitrite in water. That may be dangerous. And this one detects in a seven-fold. So each of these circles here very likely allows a detection of nitrite in different ranges. So it can span a wider range for detection. And also the color here indicates the intensity of the analyte nitrite and you can make it quantitative by using mobiles. So for this we need wax to fabricate this kind of devices and how they are fabricated. Actually, the process is very simple. That's why people, researchers, are moving to this platform and experimenting with this technology of paper-based microfluidics. So what do we do? We just draw a pattern in the computer. And later comes the magic here. We print it with a wax printer. There are commercial wax printers where you can print these patterns. And after printing, the pattern will be printed on top of the surface of paper. So in order to let the liquid flow the direction specified by the wax patterns, you need to reflow these wax. So how do you do that? You melt it in an oven or in a hot plate so the wax enters the paper and defines the channels inside the paper. Yeah, this is very simple and the process of fabrication is super short. Well, for that we bought a wax printer. We bought one a couple of years ago and it was working good until we ran into some problems that, well, technical problems of the thermal head. So we called the company once and then they came and they repaired and then a couple of years later, one year actually. We had problems again. So when they come, they said, no, no, we don't have much spare parts now. So we have to wait for a while and then when we call them the third time, then they said, no, no, we don't have the spare parts anymore. And the thing is that Xerox in this case is discontinued the fabrication of these models. So then we say, well, we buy a new one then. So we bought a new one. And then this one hasn't run into problems but we saw also in the web page that Xerox is not fabricating new models anymore. And later we wanted to buy wax cubes for printing. And now our usual supplier is not providing them anymore. So we are looking for other suppliers and probably they will disappear in some time. So if we don't have this anymore, then we cannot do our research anymore. So here is where free and open source hardware comes to rescue. A couple of years ago, I read this book. It's very good one. I recommend it to you. It's called Open Source Lab. And it was very exciting to read it because it basically says that you don't need to buy very fancy equipment. You can fabricate your own equipment and set it up in your lab. So from this researcher, his name is Yushu Appears. So once I read this book, I was very excited. And later this was released in 2013. And then in 2016, he wrote this paper. It's called Open Source Wax Reprap 3D Printer. And when I saw this, when I thought, wow, this is the solution for us. If we can build our own wax printer, if we can build our own wax printer, then we're safe. And we can maintain the printer by ourselves. So this is what they did. They took, well, this is more or less old, right? So they took a reprap Prusa Mendel and they modified the extruder here to be able to extrude wax. Now, this is more or less how the extruder looks like. And well, I saw this paper. We had the idea to build our own, but we didn't have hands to build the thing. And luckily this year, thanks to this program from KMUTT, it's called Taiwan KMUTT internship program. We got three students from Taiwan during two months in our lab. And when I saw their backgrounds, I thought, well, this is our chance to make the project real. So two of them are mechanical engineering. And well, in the program of mechanical engineering and one in the program of material engineering. So it was perfect for the project. So I thank to them for initiating the project that we hopefully continue and improve. So it was a challenge for them as well because even when they are mechanical, well, they are in the program of mechanical engineering and they can do this kind of things very easily or with not much problems. They didn't have much experience on programming and in electronics. So it was with experience for them because it is sort of multidisciplinary project for them because they had to get in a bit of informatics and programming and also get into a bit of electronics as well. So they had to study the firmware. Well, at least the settings of the firmware from Marlin and adapt it to make their extruded works. And this is after two months of hard work, what they got. I thought, yeah, this is more or less what I expected that they could build the machine. But I was not sure whether the machine would work properly after these two months. So well, they did, they worked very hard. They did very well. And the machine is partially working so far but now we have to continue ourselves because they returned to Taiwan like a couple of weeks ago. So the machine now is built with Prusa iteration three. And this is how their extruder looks like. We had to modify the parts to fit the components that we have in our lab. So we didn't spend much money on this. And it consists of a motor that pushes the piston of the side inch. And the outside of the side inch is covered with a copper tube. So the copper tube is connected with a heater, a normal heater of a 3D printer. So the tube hits the side inch and the side inch contains wax. And when the wax is molten, then the piston pushes down. And a couple of days before they left, they tried to print wax actually. The only wax we had at that time in the lab was candle wax. So well, we tried with that. And the results were not good because candle wax from the experience we got melts very quickly, yeah? But also gets cold very quickly as well. So when the wax is molten here and then reaches the end of the side inch, it gets cold very fast and blocks the tip of the nozzle. So it was very difficult to print with wax, with candle wax at least. And later, well, due to time, we told the students, okay, well, just try with Vaseline because Vaseline is also oil-based. So it should block water as well and it is a bit viscous. So probably you can print with that. And they tried and they actually could print the pattern. I don't know whether you see the pattern here. And the other good thing of the 3D printer is that it comes here. Yeah, is that it comes here with a heater. So with this heater, we can melt the wax again and reflow it to get inside the paper. So this is how the printed pattern looks like. And after melting, well, you see that the wax got, well, Vaseline in this case, got inside the paper and could actually fabricate the channels. Later, the students tried with liquid here and the liquid actually could flow. But Vaseline is not very good. So some of the sample you see that went out. So what is remaining for us is to try with different kind of wax. So instead of candle wax that doesn't work that because it's too, let's say, it has low in thermal inertia, let's say. And Vaseline, that is not, it's like very viscous, it's like a paste. These are very two very extreme cases. So we would like to try with something like in the middle like these waxes that girls use for depilation or also paraffin wax as well. Yeah, they are more or less in between in terms of physical characteristics. So we have to try with that first. And well, at least the thing is working now. And well, to close the talk, I will give a couple of final words. For the students, it was a very good experience because they got aware of the importance of free and open source hardware. Because they realized that if we build our own machines, then we can give our self support of the machines and get more independent from the companies. Also, it was a good experience for them because they required like multidisciplinary knowledge. And in terms of design, they got aware of these five, well, these four freedoms from software that we can also apply to hardware. The first one, when you have a design of hardware, you need the freedom to make the device. And this is related to patents, so they got aware of patents or patents as well. And second, they got all of the information to read about the design and modify the design. So they got aware also of copyrights. And also regarding copyrights, they got aware that the formats they were using were not open, so not everyone could read their files if they wanted, so we have to translate it to open formats. And also, these open formats would enable other people to modify our design if they wanted. So to close the cycle, we still need to put this in the internet so other people can modify our designs and complete the cycle. Do I still have one or two minutes? Yeah, no? Yeah, two minutes, good. Because I want to show you the videos of the printings. These are very short actually. Oh, where is the VLC? Well, it doesn't matter. Yeah, yeah, I will just double click. Oh, no. Yeah. Oh, it was working, but now it's not. Okay, yeah, if it doesn't, then don't worry. Yeah. Oh, no, it's not there. No, it's this one. Open with VLC, yeah. Thank you very much. Yeah, that's one. So this is a video showing when we are printing candle wax. You see that, well, at the beginning it was very liquid. Ah, yeah. At the beginning it was very liquid because the temperature was too high and we couldn't control the printing. And later we decreased the temperature to control a bit better the printer, but still we couldn't control the printing correctly. And this is because of the temperature that changes too quickly in candle wax. And the second one, the second one is when we printed with Vaseline, you see that the control is much better. We actually could print, but as I told you before, the problem with Vaseline is that it is not strong enough to contain all of the kind of samples that we use. So that's the reason we have to try other kind of wax. But now we have a good starting point anyway. Well, thank you very much for your attention. And well, if you have any questions, you're welcome to ask. Or if you don't have questions now, you can ask me later during the breaks. Thank you very much. Thank you.