Embedded - 448: Little Squiggles All Around

Episode Date: April 27, 2023

Carl Bugeja makes actuators out of PCBs, puts them to work flapping origami bird wings (or moving robot rovers), and takes videos of the whole process. Oh, and get this, self-soldering circuits.  First, origami: flap actuators video. Your source for the PCB actuators: flexar.io Carl’s YouTube channel is filled with hardware, software, successes, and misses. Check out his tiny foldable rover and the self-soldering circuit. His projects are open source so you can find the information on github.com/CarlBugeja Carl has a site (carlbugeja.com) and shows his projects on Instagram instagram.com/carl_bugeja Elecia worked on a zero-heat-flux, deep tissue temperature measurement system. Transcript

Welcome to Embedded. I am Alicia White, alongside Christopher White. Let's talk about PCB boards making themselves move and then soldering themselves and origami. It's going to be a good week. Our guest this week is Carl Bugea. Hi, Carl. how are you doing? Hi, thanks for having me.

Could you tell us about yourself as if we met, I want to say at an origami convention, but yeah, at an origami convention, sure. Sure. So I'm an engineer that lives on a tiny island called Malta in the middle of Europe. So my job is to design weird and novel electronic projects and document all of them on YouTube. And we will be talking about many weird projects. But first, lightning round where we ask you short questions and we want short answers okay are you ready yes uh what's your favorite fictional robot okay um i guess it has to be woolly what is your

favorite origami pattern um it's good to be in the crane or this one i I guess. Flexible or rigid PCBs? Flexible. Can flex circuits be made into origami? I think so, yes. Do you work on one project at a time or do you have several in the queue? Unfortunately, several. How far

can your fold-up rover go in one charge? I think it can last around 15 minutes, but it heavily depends on how smooth the terrain is. So on rough terrains, it needs to have the battery fully charged to keep going. Is that 15 or 50, almost an hour 15 minutes 15 minutes if someone were to visit malta what restaurant should they go to it's hard to tell because there are so many restaurants here open

in the last five years it's a little bit crowded to be honest. But there's a lot of Italian cuisine and stuff like that. So I think you have several options to choose from. Do you have a tip everyone should know? I guess to never give up on anything that you're working on, I guess, because somehow eventually you can get it to work. That is a great tip. So I do want to talk about your origami actuators. DJ, a listener, sent in that video. But while we were talking about scheduling this, we then got another video about a fold-up rover and then

another one about a self-slotterian circuit. So where should we start? um let's start with the actuator stuff i guess because um that inspired a lot of the fold over as well so you folded a bird and a dog and just a flex circuit. There was no traditional motor solenoid thing. How does that work? So the idea actually came about when I was, so I had already developed the flexible actuator and the PCB actuators. And then I had one project where I tried to turn a heater into a sticker and see how and what applications it could be useful in. And when I was sort of testing it,

I realized that putting an actuator on a sticker sort of doesn't exist and would be very useful in some cases especially in origami because flexible PCBs are like paper then so so the idea was to develop a sticker actuator that actually um connects to paper and sort of you could bring life into origami. Going back to the heater, I actually worked on something similar. It's interesting because we were making a thermometer that was non-invasive. And so you stuck the heater onto somebody's forehead and it had some insulation and then you heated it such that there was no temperature gradient between the heater and the human skin.

And that was deep temperature measuring. I don't remember the acronym for it, but it was kind of cool. Have you done stuff like that so um what i have done is try to apply sort of um one time i have i had received um like uh an email from a scientist um in algerentino and he actually told me that he's using my actuators as heaters so basically what he required is like a heater that is paper thin so my flexible actuators were just 0.1 millimeter thick and sort of I had this sort of

let me try and actually put a heater on flexible PCBs instead of using my actuators as heater and there were quite an interesting quite a few interesting results

in that experiment, I think. Did you melt any flux circuits? Yeah, I sort of tried to heat them to their limit. So basically, flexible PCBs are rated to 100 degrees Celsius and what I what I try to do is to run a long duration test for around I guess it was two weeks or one month, something like that, because this was more than a year ago. And it's actually the PCB that I was testing eventually turned into this brownish color. It was still functional and it was like non reusable, but, um, I, I mean, it was still cool to see that the limitations

of these, of these circuits, but then eventually I also learned that the so flexible PCBs, um, there are different colors and for some reason they are rated at different temperatures so the black cover lay um was um should sustain higher temperatures than the brownish one and that that was the conclusion for that project sort of you did something sort of similar with self-soldering PCBs. Yes. Could you describe it? Yeah, that project was actually stuck in my head for around five years. And after thinking about it a lot, I eventually decided to give it a try. Viewers from my channel probably know that I first tried to create a PCB hot plate.

My plan was to first create a hot plate, then try to tackle self-soldering circuits. found out that there's a lot of things to learn from my side about PCB heater, so it wasn't that easy as I thought it was. But eventually, from all the testing that I have done, I have found that PCB hotpl plates are actually a very bad idea because PCBs are not rated to go to high temperatures for a long duration of times. So basically, the conclusion was that a PCB hot plate would be only used four or three times maximum until it starts getting damaged.

But this still made the self-soldering circuit feasible because you only have to solder the circuit one time for the self-soldering concept. And once I eventually reached that point, I tried to make the video as geeky as possible, I guess. You said not long duration and one time. That makes sense because the boards have to get hot enough to be soldered normally. Exactly.

And on the inside, if I remember correctly, you took a plane that might normally be a ground plane. Exactly. Instead of having it all copper, you made little squiggles all around except for where there were vias. Exactly. How did that lead to heating? Did you have a short to ground? How does that work? Imagine a resistor. When you pass current through it, it heats up. The same goes for a copper track. If the resistance is small enough,

it will heat up. My idea was to use low temperature solder paste to heat it up so that it could follow the soldering reflowing profile. Are the squiggles to increase the resistance so that it heats up? The squiggles are just to make the trick longer because you have to achieve the resistance have to be high enough so that the current won't be too high and I could be I would be able to just power it with like nine volts or something like that or 12 volts that is why I try to increase the resistance as much as possible. It was an interesting video that you could make one of these from another one of these,

the whole mother baking the daughter thing. But would you do this in real life? Are there production uses for this? I mean, for hobby projects, I think it's perfect. But for someone who doesn't own a reflow, perhaps, sorry, a hot plate. But for production, I'm not totally sure, because one of the biggest criticism that the project received was that um sort of in engineering school they teach you that ground should have the shortest path as possible for high speed circuitry um so

most probably this circuit would either um does not pass something like an EMC test or something like that. Um, because it's actually, um, has a very bad ground plane, even though I had a separate, um, ground layer underneath it.

Hmm. But you could rectify that by right now you connect your squiggly layer to the ground layer to have two ground layers. But if you just, instead of connecting it, left it floating, then that wouldn't matter, would it? I don't think that that would matter. to do some more testing on this so that I can perhaps create even a better version with less, less swiggly lines and the shorter path to ground. I'm still sort of brainstorming at the moment on how, on how I can create a better version. But I mean, for me, it was just a cool concept that I had to try out. I think it's one of those concepts that is so novel to me anyway,

that I can't readily see the application, but I know there must be some really cool application for it that i'm missing and this is not a criticism it's a this is so outside what i would expect somebody to do that i have to process it for a while but i think i mean it's kind of along the lines of you know all the self-assembling or self-repairing kinds of things like von neumann machines and all that uh that i feel like, yeah, okay, maybe something that needs to repair itself could have a whole array of these layers and

okay, well, this isn't working, we'll try to reflow this one part of the circuit or something like that, but it just seems like there should be really, really important applications of this. Yeah, I mean, for repair, it would definitely, there were a lot of comments suggesting it to be used in repairs or even even for something that has like a critical data where if for example

if stolen the pcb has to self-destruct. Or someone even suggested using the heater to keep satellites warm from the cool environment of space. So there are a lot of areas where this could actually be useful. I was starting to think of things like places where you don't necessarily have all the tools you want, but it's difficult because you also do have to solder paste it and put all the components on. So it's not like you can do it in a field test unless you have a very quiet place to be.

But I started, you know, could you do it in space? Why would it be better to do this in space than to have it heater? Or could you do it in Antarctica where you don't necessarily have everything and you want to be able to configure circuits on the fly? Yeah, it can be portable i guess by just connecting a battery but the space idea was just related to um keep it keeping the actual circuit warm not soldering it i guess but i guess it can also be soldered in space, but it would be messy, I guess. If you went to Mars, what would you need to take with you?

At some level, you don't know what you need to take with you, so you need to take flexible things. So it was the same perspective as Antarctica for me. You could also selectively blow parts of it. If you had a whole array of these, you could blow parts of, like if you had like a whole array of these, you could address parts of the circuit with a heater, you could like blow fuses that way I guess, or blow up

an EPROM. Just one though, not the whole thing. Trashy, yeah, I mean. I'm going to selectively modify the circuit. But you also in an effort to scientifically determine the maximal limit, you also set one of these on fire, which I found highly amusing. How far did it go?

What was the power where it just said, no, I'm not ever going to work again? So PCBs are rated, their material are rated on a parameter called TG rating. So usually the highest rating, for example, for the PCB that I used was 170 degrees Celsius. I'm not familiar with Fahrenheit, so I'm sorry. You can translate it if you'd like. Hot, very hot. Above 300, way above boiling. So trying to heat up the thermal track higher than that value will damage the pcb especially for for long durations and in the test i think i i powered the track with around 30 volts if i'm not mistaken um so that's so that's brought up the temperature

way high and the interesting thing is that since that swiggly track once the pcb starts sort of getting damaged and sort of like getting melted, the tracks themselves start to get shorted. So by that process, they're essentially lowering the resistance even more. So sort of like creating a bigger damage. A cascade effect, yeah. Exactly. You just need more current after yeah. Exactly. You see more current after that.

Exactly. Okay, so how do heaters relate to flap actuators? They actually relate a bit because one of the limitations of PCB actuators are the thermal limits of the PCB. So like I said, for flexible PCBs, for example, the maximum temperature it can withstand for it to be okay is 100 okay, it's 100 degrees Celsius. So when passing current through the copper tracks, it will obviously heat up even though it's a coil, not a PCB heater. So that is actually the limitations of the coils themselves, is that they have to operate within the maximum temperature ratings of the PCB. Oh, okay. So it's basically if you take a flap actuator

and use it too much or power it too much, it will burn itself out not not at one at a much higher voltage it it will but um even at say i usually try to keep their voltage ratings below five volts but even, if you power it at 8 volts for like one month, it will eventually damage itself. And we haven't really described what the flap actuator looks like. And I think the way, since we're podcasting, that's always a challenge. But I think the way to start is with the circuit pen that you used to make one of these on paper. Can you describe that? Yes. So this idea came about when I just bought some conductive ink and I was playing around with trying to make a coil that was similar to my PCB actuators. The downside of that project was that conductive ink has a low conductivity when compared to copper.

So the effects are not as, the coil's magnetic field is not as efficient as the PCB one, but it worked and I did manage to attract paper with magnets. So these are basically deconstructed solenoids in a sense, right? You've got a coil and then it's acting on a permanent magnet. And the coil just looks like a spiral. Yeah. So you apply a very, very inefficient electromagnet. That's how I like to describe it.

It's an electromagnet without a coil. And so the flap actuator goes between two magnets if you want it to go all the way back and forth. Is that right? Or does it only need one? The current flap actuators I have only has one because I had a whole project trained to, because at one point I first, so I first were making these actuators for fun. Then at one point, I tried to create... I was getting into the robustness of these flexible PCB actuators.

So the reason for this was that I started observing some failures when I was powering these coils for one week or two weeks. So the goal was to create a flap that could sustain, sort of could be powered for like a year or two. And the advantage, the good thing about this is that now I sort of have like a template for a flap actuator that can actually be robust and be used in projects like mechanical displays and where I'm now confident that it wouldn't fail for a long duration. Mechanical displays, say more about that yeah so one of my um future projects is will be a display made out of these flaps it will be sort of like a mix between a flip dot display

and kinetic sculpture um and like I was saying if I haven't just focused on the durability of these flaps going for this new project would be very bad

I guess because it wouldn't it wouldn't have lasted very long. I guess knowing that they can go for millions of cycles really helps the idea that this will last. Yeah, exactly. Pop-up books, electronic pop-up books where the people can move and stuff.

I'm sorry. Thinking of other things you could do with this. But I can't just drive this flux circuit from my normal processor. I can't just hook it up to an Arduino and hope that I don't source enough current to blow up my chip. Yeah. Arduino won't supply enough current. What you need to drive it is either a MOSFET, a single MOSFET

transistor, but that would actually control it in control the current in one polarity. You can also use an age bridge where you could reverse the current and actually flip its polarity.

And that's how you get it to go back and forth. When you want it to be close to the magnet, you have it go one way. If you want it to be far, you have it flip its polarity. And then you have a kit with those. They're the Flexar drivers. Those are the H-bridges. Yes. So I have a website called flexar.io.

And there I sort of sell a kit where people can experiment with this directly. The driver, what it does is basically has five functions, and you can basically switch between each function to see, because the actuator, for example, can also be used for buzzing, making a sound. It can either be used in a square wave mode or in a PWM mode where it sort of is driven with like a triangular waveform and stuff like that. Have you looked at reversing it to make sensors? Like you could make a little paper keyboard or something?

Yeah, I'm not sure if it can actually be used as a pressure sensor, but it can be used as an inductive sensor. There are many applications and also development kits that are using PCB coils for inductive sensing. Okay. Where it can either perhaps detect a magnet or detect a metallic object. They have also showed it in some of my videos as well. Like a paper microphone.

Yeah, we actually saw that. Oh, did we? I mean, I don't know that I saw it from Carl, but I saw something about it. Have you done a paper microphone? I haven't done it yet. I mean, with these PCB actuators, because I guess it cannot generate magnetic field. It would be too weak, I guess. You'd have a big low-noise amplifier. You would need a really large too weak I guess you would need

a really large gain I guess it would be a fun project though to do that so you show these on YouTube and you sell these little kits but they're all open source so

if I wasn't lazy I could make my own do you make most of your money from YouTube? Yeah. So I make my income from two ways, from these projects and from the kits I sell on my website. Even though all my projects are open source, the good thing about YouTube is that first you're documenting everything in your videos,

which would be very helpful to a lot of people. While doing this, you will be also building a community um which obviously by by watching your videos will help you make more videos um then i also have a patreon um membership um where i have a lot of members that are supporting directly my projects. And I also have a couple of sponsors that fund the PCBs and actually the projects themselves. How did you get started? What came first, the kits or the videos? The videos came first. So my first video on YouTube was about the PCB motor.

And then I spiraled my way down to PCB actuators, flexible actuators and stuff like that. How does a PCB motor work? So a PCB motor works like every other three-phase brushless motor but instead of having windings wired windings the

coils are printed onto the circuit themselves and then you have a rotor on top with a couple of magnetic poles and by providing a commutation signal, the rotor rotates. So you're doing the whole three-phase commutation where you are right now it depends on what signal you get because you're trying to throw the motor around based on changing electrical signals yes it's usually

in a closed loop um in a closed loop orientation it's based on the position of the rotor that's hard i did that once and i managed to get some beautiful oscilloscope traces and yet the motor just kind of fell there no no the motor was a student i was sort of creating like um a brushless motor esc and it it was pretty hard and challenging to do it because it's it you have to have very very efficient code um to get the motor rotating at very high speeds. Because if you have just a little delay, it will lose commutation.

This is one of those cases where you actually truly need real-time response. You can't have any latency. You can't do this in Linux. I don't think so, no. Depends on your Linux. I'm sure if you applied enough CPU power.

I don't know. I don't know what I'm talking about. I mean, for low speeds, I'm pretty sure you can do it. But for very low speeds, motors, I'm not sure. It becomes untenable pretty quickly. I used a TI Piccolo because those seem to be very designed for this problem. But I think in your videos you're using a PIC something? Yes.

So my ESC sort of went through phases because at first i started with a pic 16f then i switched to a dspic my controller then um for the rover i switched again to the pic 16f because the dspic was out of stock everywhere and so it's at the moment it's pretty pretty all over the place, but I'm planning to make a whole video just about speed controllers and how it can actually... I will go in more detail about PCB motors and how you can select the most efficient ESC for your PCB motor application. Cool. I look forward to that one.

And please add some oscilloscope traces because they're so pretty. So make sure I understand. So the PICs are being used solely as speed controllers. So if you wanted to drive several motors, you're going to have a higher level microcontroller that's talking to all the PICs and telling them how to adjust their speeds? Yes. Okay.

That's how my rover was working. So it had four PIC-16F microcontrollers, and the ESP32 was talking to them, basically just sending the speed. And the ESP32 was also talking to your Xbox controller? Yeah, it was using a PlayStation controller. Over Bluetooth? Yes.

Oh, neat. Okay. I think I missed that from the video, is how that was connected. Over Bluetooth? Yes. Oh, neat. Okay. I think I missed that from the video is how that was connected. So that's cool. So this rover that we're talking about, everybody's thinking like a mouse droid from Star Wars,

something, you know, at least calf high. But this is tiny. Yeah. How big is your rover? I don't think i ever measured it but it's quite small it's around i think the battery was i believe 4.9 centimeters in length and the battery is pretty much the length yeah Yeah, exactly. I think the wheels go a little beyond, depending on which you have printed up. Exactly. It's around five centimeters in length, something like that. Yeah, it was tiny. And that, of course, causes its own problems because it's not heavy, which makes it easier to go, but harder to get traction. Okay, so the hook of the Rover is that it uses these PCB motors,

but actually the structure is also PCBs, so it folds into itself, right? It folds into a cuboid. Did you ever try tracks instead of wheels? I haven't, but it's one of the main points that is highlighted for the next version. But before thinking about that, I'm just focusing on the motor and trying to squeeze a little more torque out of it so um my first step for the the next this next rover is just going to be just focused on the motors and trying to get more torque out of them how do you how are you trying to do that like i can see that the pcb presents some limitations about how physically things can be structured so what what things can

you adjust to get more torque yeah there's actually quite a long list um first of all the most obvious thing that can be done is adding more poles so currently my motor has six poles. Going for like a nine pole motor would like increase the torque. The only problem with that is the area. So I'm still not sure if nine poles can actually fit in that area that area and if not how much bigger does the motor needs to get but then there's a lot of other stuff that can also be tested something like for example a lot of people suggest hold back arrays for example my rotors are quite small so I'm still not 100%

sure that the magnets would fit inside that and have that orientation but I mean I'm still experimenting with a lot of stuff currently. You put this experimentation style of development on your YouTube channel.

You also put your mistakes on. How do you decide what you're going to put up? How do you decide what mistakes are too embarrassing to show on video? I actually try to put everything in the videos as long as it obviously follows the same arc of the video. But there are some things that obviously would make the video last forever. So, for example, for the rover, I was having a problem with the PlayStation joystick communication because I had another joystick that was like a mock-up and it wasn't working with it.

So I spent like weeks trying to solve this problem and I eventually didn't solve it. But then it comes to how long will the video is going to last and is it like important um for for the the build so there you sort of have to make some decisions what to leave out and what makes the video interesting. It must be difficult to have the balance of making the video interesting and fun and entertaining, but also showing the engineering in a way that is understandable to the people who are interested in that sort of thing?

Yeah, it's very difficult. I think it's... I'm always sort of not 100% sure how video is going to go, but I try to keep them as fun and as interesting as possible because my goal ideally is just to build an engineering community. So with that, you have to sort of make the video interesting for engineers and for students and people that are just starting out. Have your videos gotten more technical over time or less technical? I think, I'm not sure.

I think they have become more technical, but I am always trying to explain the technical stuff in more fun way so that sort of the students and people that don't have an engineering background can still understand them. And that's why your self-soldering video made me hungry. Let's see, I have a couple listener questions um maddie c wanted to know where you get your inspiration for your designs okay so um so some ideas are are just like I don't know I came up

I come with them in the shower or something like that the self-soldering circuit was one of them for example because like I said this has been five years in the making this idea so

but a lot of other projects just start by creating other, finishing up other projects. So for example, the PCB motor project, I started working on the new version as soon as I finished the rover. And a lot of my projects, I think, are created that way. Do you have any that you've put on the shelf that you wonder if you'll ever get back to? Yes, actually. I have some projects that happened before YouTube.

So before I was posting video, I was still working on some other stuff that maybe someday I will revisit. That brings up another question from a listener. William asked, what motivated you to start a YouTube channel? And you've mentioned community. What is the Maker community like in Malta? Pretty zero, I think. what is the maker community like in Malta? Pretty zero I think there was

the first maker fair that was going to happen got cancelled because of COVID so but I think it's improving with time let's say that because currently they're trying to motivate a lot of young students to get into the STEM world.

So it's improving. But when I was young, it was hard to find a friend that was into this kind of stuff. What are some of the other motivations to start the YouTube channel? Yeah, so basically, when I finished my engineering course, I started a startup with my friend. And during that time time we were experimenting with a lot of interesting things. But the startup eventually failed because of financial issues. But I remember saying to myself, we have done a lot of research and sort of documentation wasn't very good if

perhaps we have put all this stuff on youtube or hackaday or something like that um maybe it would have been beneficial um to others and maybe also to us because you actually have to show what you're creating. And that's when I started the YouTube channel, I think, after that failed startup experience. In school, could you have imagined um doing youtube as a as a job no i was very shy um if you watch um my first videos um they are they are horrible to watch but when I was at university my passion was always trying to invent new things so at one point we also had a group of four friends where we weekly discussed new inventions that we could invent

and create as a startup or as a business. And I think YouTube is the perfect place to do that because when it comes to hardware, it's very, very hard to start a startup hardware because, first of all, any hardware project starts with R&D. And obviously, during that phase, the whole project could fail or from the research you have made, it would be unfeasible to do. So YouTube is the perfect place i think to do that because um even if something doesn't work you you still showing people what you've learned um which i think is is very entertaining as well.

And the education part is admirable but if you want to have a new startup with a new invention if you're giving away all your ideas how will that work? So you're referring to us putting them as open source?

As open source as explaining them on YouTube? If you invent something that you want to have a startup about, do you think you can be as open about it? Yeah, I think you can because as you go along, people will start also putting their ideas in your comments and suggesting if the idea is feasible or what sort of applications would they use it for. And I think by putting it as open source, you're first giving it to the community so anyone out there can build it yourself.

And like I said, by having this community, if someone, for example, copies you or uses your idea. Like people still, for example, one time it happened on one of my projects, people will sort of still comment that sort of, have you seen Karubu Jaya's video about? So there's still sort of the feeling of a community behind it so on your videos they comment have you seen your videos no no on other if if they for example someone tries um to create something something similar or stuff like that. It does happen, though.

People do comment on people's own stuff and say, hey, you should check this guy. I am that guy. I've had people ask me interview questions straight out of my book. And it's like, maybe you should check the book. Let's see. William had another couple things to say but also please let him know i've been watching his channel from almost the first upload i really respect his enthusiasm and creativity thank you very much um where do you want this to go go self-soldering self-folding self-driving robot

or YouTube star with 10 billion followers no I don't I mean my goal in life is just to keep inventing stuff I guess even if it's

I mean some of my projects, I think cannot actually be turned into a viable product. So my goal is to just keep improving some of them and try to create a better future, I guess. One more listener question from Peter. What kinds of projects would you recommend for someone looking to learn more

about designing foldable circuits? Foldable or flexible? Let's go with both. Foldable. Foldable, okay. So my suggestion would be to first start with rigid PCBs and use connectors or soldering bridges to connect the PCBs together

if you haven't obviously done a foldable circuit before because that way it will give you a good idea of um the clearances and stuff like that of the pcbs and um things that you have to be careful um that perhaps don't pops pop to your mind when you you're designing things um i think that's a good way to start. If you have seen my foldable rover, if you have seen the two-wheeled robot, so before the foldable robot, there was a two-wheeled robot. That robot was actually connected with connectors. So it had three PCBs in total that sort of formed a U-shape and were all connected with connectors. So it had three PCBs in total that sort of formed a U-shape and were all connected

with connectors. That raises a question that I had in my mind earlier and forgot to ask. Are you doing anything with the coils or with any of the projects? Some of them you're doing on flex circuits, some of them you're doing on regular PCBs, but are you doing anything where the manufacturing places for the PCBs come back to you and say, what are you doing? This is weird, or this is difficult, or...

One of the sponsors is the PCB manufacturer. Do you get special treatment for that? Do you get to have special circuits? No, I don't think so. I mean they they sponsor everything that i ask for but um the but they do come up with like because their marketing team is different than their technical team so um when it comes, for example, to flexible stiffeners for flexible PCBs, I tend to either, for example, for the Baro overhead, around six of them.

So they do come back just to, for example, to verify if they have understood the file correctly or like how many stiffeners do have. I am working on a new project, for example. It's just a small actuator, but for this actuator, so this actuator has a flex chair

I'm not sure if you know what flex chairs are they are used in plastic normally there is a lot of 3D prints currently with flex chairs and

stuff like that. They're really popular. And I'm trying to integrate them into PCBs. And for this specific design, I had the same model for like 10 times. And for them, seeing all these stiffeners got them crazy. So stiffeners has been one of the areas they've asked about anything else yeah they all the shape some of my um my shapes for example the i made a wearable heated vest which was around 70 centimeters big. That was, so imagine a PCB almost as big as one meter, very close.

Wow. So that was strange to them. I once made like a Christmas tree that sort of unfolds. That also raised a lot of questions on their side. The RGB ball also had a very weird shape. Right, right. I imagine they're getting used to it by now. Yeah. For a few projects I submit, I expect a follow-up email from their site.

Going all the way back to the flap actuators and thinking more about my personal projects, usually when you have them, they're flapping back and forth to their full extent. They're making a large motion very quickly. Can I make that same motion but slowly or does it have to be fast? Yes, yes. It can also be slowed down.

You just have to tune the frequency of your signals. And it can actually be made quite small. And if you install a square wave, you create a triangular waveform, the motion is very organic. It's like sort of, for example, a wing for a bird and stuff like that. Because it's not just on, off, on, off. It's slowed down. Cool. I have an origami jellyfish pattern that I want to try.

And so if I get a kit and I get the flex if you get a kit if you ship the kit that i order and i get the flex our board and the the the flap do i need another controller don't i i need something else to tell it what to do. The driver actually has an onboard controller, so you can just sort of plug it in and it will work. But it also has an option to provide external signals, so you can also control it with your own microcontroller if you'd like. Like SPI, I2C, UART?

No, it's just the two PWM signals that drives the HBridge module. And can I reprogram the PIC that's on there? Yes, you can also do that. In the datasheet, there is the description the um programming pins and what they are do i still have a pic programmer i might i'm sure we have a pic programmer somewhere in a drawer all the programmers um have you tried to get like a heartbeat in a stuffed animal instead of a flap? Heartbeat? What do you mean? Oh, you want to make a haptic engine out of this? Yes, I want to make a haptic heartbeat.

I think you can do it with the 12 layer PCB coil. It depends on how much you want it to have, how strong you would like the vibrations to be. How come you didn't make this about 20 years ago when I wanted to put it on a t-shirt? Can you go back in time and make this? You were eight. To be fair, I mean, the physics of this was there 20 years ago. Yes. Yeah.

But those little Vibe coin cell batteries, coin cell motors never worked the way I wanted them to. Do you think this can be a replacement for some of the haptic motors? I'm not completely sure because I have some experience using haptic motors and some of them produce a large vibration. My goal was never to create a haptic motor. I just wanted to use this for robotic applications and other stuff. But I think if tweaked appropriately,

the 12-layer coil can be used as a haptic device as well. Well, if I get it working, I'll let you know. Carl, it's been really wonderful to talk to you. Do you have any thoughts you'd like to leave us with? No, it's been really fun talking to you guys. So thank you so much for having me on the show. Our guest has been Carl Bugea, electrical engineer and YouTube creator. His channel is Carl Bugea, which is C-A-R-L-B-U-G-E-J-A. And of course, there'll be a link in the show notes. Thanks, Carl.

Thank you so much. Thank you to Christopher for producing and co-hosting. Thank you to DJ at RIT for recommending Carl. Of course, I love all the YouTube origami videos you send me for everyone. Oh yeah, thank you to our Patreon listener slot group for questions, and thank you for listening. You can always contact us at show at embedded.fm or hit the contact link on Embedded FM. And now a quote to leave you with from Akira Yoshizawa, a pretty famous origami guy. My origami creations, in accordance with the laws of nature,

require the use of geometry, science, and physics. They also encompass religion, philosophy, and biochemistry. Overall, I want you to discover the joy of creation by your own hand. The possibility of creation from paper is infinite.