Electronics for Non-EE’s - Hands-On Workshop

MATT BERGER: So my name is Matt Berger, and I run the EAGLE team at Autodesk, amongst other teams. So I'm also responsible for Tinkercad. I was responsible for 123D, and a variety of other products, mostly related to the consumer, and the sorts of things that are really intended to drive the Autodesk role in the maker-hacker emerging market startup communities moving forward.

This is who I am, if you need contact information, if you want to look at any of my open source hardware projects, any of those things. I used to run product at Supplyframe, which is a company that owns Hackaday. So if any of you are Hackaday readers or avid Hackaday readers, follow Hackaday projects or anything like that, you'll see me in the comment threads. You'll see me on the chat all the time-- obviously not during work hours, because that would not be a good thing.

I self-identify really as an electrical engineer. My background is really related to radios. I love to build radios and RF stuff, wireless stuff.

I love materials problems. I love physics problems. My education is in applied physics. I really like physics problems.

I also do a lot of teaching, a lot of mentoring, really trying to build opportunity through technology and enabling people to build stuff that they just couldn't build before. If you are interested and you think that what we talk about today is interesting, you happen to be in the Bay Area, if you're down in LA-- I'm going out to New York just after the holidays. I do a lot of stuff on the road where I do a lot of workshops that are generally free to the public, things that I do out of my own pocket just as a way of trying to contribute as much as I can to people's understanding, and education, and how they can transform things through science.

So a lot of interesting things that I build-- some things robotics, and I started doing model rockets at a very early age. I won't belabor too much about this kind of stuff. That's a Hackaday logo up in the upper right hand side over there, which I love, which is that skull and wrenches. Sorry if that looks ominous. I promise it isn't at all indicative of anything that you should be afraid of in this class.

Let's just level set first, though, before we get started. I want to be absolutely upfront with you. This was my desk before I left and came here.

And I want to stress that, because I think it's one of those things which is lost in a discussion about coming up to speed on how to build things with electronics, the fact that, hey, there's somehow this perfect workflow, and everybody follows this perfect pattern, and it's predictable, and everything looks very clean. Look, all of that stuff which is connected together-- there's an FPGA board down there. There's an Arduino there. There's a breadboard, some stuff that I did on a breakout board.

That's very real. I'm testing an SPI multiplexer that allows the Arduino to program an FPGA using wireless connection up to the cloud. So this is real. It's sitting on my desk right now.

It is a big mess of wires. And it's ugly, and it's nappy. And everything about it is probably not terribly flattering, not reflective of-- not a reflection of my best engineering skills.

But the point is is that I get the job done. And, at the end of the day, I want to stress what this really represents. All we do when we build electronics or we build printed circuit boards is connect components together in interesting ways, unlike mechanical engineering, which has a different problem.

Mechanical engineering has the problem of you may be creating a part which has never existed before. In the electronics space, almost invariably, with very few exceptions, we buy 100% of the components that we use on our circuit boards. So we go to a third party company that's a distributor for some larger manufacturer. We buy a part, which is purpose built for some specific function or some set of functions.

And so, in this case, all I'm doing is connecting components together in interesting ways. If you rewind all the way back to your fifth grade electronics class or your fifth grade science class-- it was probably just general science at that point. I don't think you had an electronics class.

But that battery light bulb switch concept, that's all we're doing. We're just doing it at scale. And we're scaling it up.

And the interesting thing is is that more and more, we're moving towards a platform approach to electronics. So it used to be that 10 years ago when Arduino came out I would look at the Arduino and say, oh, it's great but don't you know that I retired my old spring-loaded Alinco electronics kits 25 years ago. And I'm not touching those.

But the truth is is that it's super convenient. It's super convenient. And it's a software platform that allows somebody who is a non-engineer, non-physicist, and non-materials person to interact with the real world.

And that is what makes those things so relevant-- so Arduino, Raspberry Pi, BeagleBone, Gumstix, you name it. You can go out and find all manner of companies that are building these platforms that allow you to write software that can control the real world.

So if I'm a mechanical engineer, I'm an industrial designer, I'm an artist, I'm a maker, I'm a hacker, I'm a this, I'm a that, I no longer have to have all of the requisite information required for me to go out and start to engage and start to build things. Instead, I can use somebody else's platform, which provides me a gateway without having to know all the low level details.

So me as a 25-year electrical engineer-- and paid electrical engineer-- and somebody who's got a background building ECAD software, this is on my desk today. My prototyping platform is an Arduino and a breadboard. And it looks a lot like what my dresser looked like when I was 13 years old-- again, not terribly flattering. It probably didn't do a lot for my social life, but definitely important.

So in ECAD world, in the electronics design world when we build a printed circuit board, there's two views of the world. There's a symbolic representation of the world, and then there's a physical representation of the world. And if you extrapolate that even one step further, there's a physical representation of that with geometry, with three dimensional spatial geometry.

In the symbolic representation, we call this a schematic. And the schematic uses symbols to describe a circuit. So on the left hand side, even though it kind of doesn't look like it-- maybe it does a little bit-- that's a mini USB connector there.

Over here, those are capacitors. And a capacitor, if I described it in engineering or physics terms, I would say, well, it's two metal plates separated by a dielectric. That kind of looks like two plates of something separated by some gap in between it. The dielectric is basically just something which is an insulator. It's a fancy way for us to say insulator.

You'll notice more and more things like a fuse up here, which kind of has that same curly thing, that if you look inside of a fuse it has that same sort of curl to it. Resistors are typically a squiggly line. The reason is is because as the length of a piece of wire gets longer, the resistance increases.

So we draw something which is symbolic, which represents exactly what that thing is, exactly what it does as best we can. Now, there are some things which are just ambiguous, some things which are integrated circuits where there's multiple functions or there are complex functions inside of those things. And for those sorts of things, we end up using something like a rectangle up here. So we'll use a rectangle. We'll add some pins to it. And what those pins are is analogous to the contacts on a circuit board where the components will make contact with the surface of the board.

So a printed circuit board, its physical representation would look something like this. And the physical representation, what we've done is we've said, OK, that USB connector-- this looks maybe a little more like a USB connector, not much. But that USB connector over here has a series of small metal pins hanging off of the back of it. If you've ever looked at a circuit board, you'll see the pins on there.

Those pins are where the electrical connections are made between that connector and whatever cable gets plugged into it and then the rest of the circuit itself. So connected to that on multiple layers on the board-- the red represents one layer. The blue represents the opposite side of the board.

So I've got a top side of a board and a bottom side of the board. The boards can be multiple layers. We'll talk about that in a second.

But in the case of this, the red represents the top side. And the way that we build a circuit board is similar to the way that we do other photolithographic processes like printing. So we start with a board which is pre-clad. What that means is it's a sheet of fiberglass with a thin layer of copper already spread over the top of it.

We apply a mask. And the mask is to protect whatever copper we want to leave behind. We drop it into a material called an-- or into a solution called an etchant.

And what the etchant does is it removes all of the copper that we don't want on the board itself. So if you imagine a solid sheet of copper, we remove the things that we don't want. It's standard photolithographic process, very similar to how we do things like offset lithography for printing.

So these little red lines, those represent the connections that I want to maintain between those components. There'll actually be a thin foil of copper on the board, something like 1.62 mils thick-- 1.4 mils thick, sorry. So those thin foil lines are everything that you saw in those wires now represented across a two-dimensional plane. So that's how we connect components together in interesting ways in a contemporary sense.

Now, the cost to build a circuit board is relatively inexpensive. To get the bare board fabricated is relatively inexpensive. But what does relatively inexpensive mean?

Meaning for $7 a square inch, I can get a circuit board made that has copper foil on one side and copper foil on the other side. I send off my artwork files, which are the things that I get out of the CAD software. And when I submit them to somebody, they send me back a circuit board seven days later, which looks totally pro. So it's relatively inexpensive to get into it. It's great, because it's sort of-- what I'm trying to do is shatter the impression that this is somehow out of your reach.

Now, as far as the design workflow is concerned, there is this conceptualization phase. Then we go into the schematic, and we draw the schematic. We do what we call schematic capture, which is capturing the idea in terms that can then be acted on in the physical space.

We do what's called PCB layout, PCB standing for Printed Circuit Board. And then we do the computer-aided manufacturing process, which there is CAM in the PCB environment. It just happens to do with 2D planar surfaces as opposed to dealing with three-dimensional surfaces.

You can use a CNC machine to remove copper from a pre-clad circuit board in the same way that you can use a chemical etchant to do it. The difficulty tends to be around-- or the trade-off tends to be around tolerances and time. I can mill a machine on my desktop and I can get the board back in a couple of hours, or I can send it off to a manufacturer.

Now, the desktop is going to have a finite resolution. It's going to have some real limitations. But photolithography is pretty accurate and the chemical process is pretty well understood.

So I can go down to 2-mil tracks or 2-mil connections between things-- and that's very, very small-- but on the surface of a circuit board that I send off to a fabricator. But I could never probably pull that off with any level of reliability using a desktop milling machine. We can get down to about 6 or 7-mil tracks, typically do that with something like an engraving bit or an engraving end mill, something where you really have to then control the depth. Because it's more depth than anything else which is going to determine the distance between those things and their thickness.

So there's all manner of different modeling and different ways to approach things. But this is an open source software called Fritzing where you can do some basic circuit design in Fritzing. We've got another program now which runs on the Tinkercad website, which allows you to do circuit design and simulation in the Tinkercad context. It's pretty amazing.

The reason I like this picture is because-- so there's reference to Homer Simpson there. So there is an episode of The Simpsons-- and I apologize if that's sort of old hat now-- but there's an episode of The Simpsons where Homer buys a grill. And you see this amazing picture of this grill. It's this brick grill that he's going to make out in the backyard and whatever.

And as the camera cuts away, it's actually him looking at the picture of the grill on the back of the box. And then he falls to his knees. And that's the grill that he built-- so beautiful, orthogonal, clean. Again, what's sitting on my desk right now? Hovering, hanging above wires, dangling things, all sorts of stuff-- I could be out by it. I could be frustrated by it, whatever.

At the end of the day, you learn to develop a sense of humor. It's like these days nobody cares when they walk by a room full of software engineers and everybody's got Stack Exchange open. You have to abandon the idea that you are somehow required to know everything.

There's a great quip by a writer that I like, a guy named Kevin Morris. And Kevin says engineers are in constant fear of being found out. And that's absolutely true. Oh my gosh, somebody's going to ask me something and I don't know how to do it. [GASPING] Dare they find out that I don't know something.

So let's go ahead and level set. What is a PCB? And, again, I mentioned pre-clad circuit board. This is an example of a pre-clad piece of circuit board. You can produce circuit boards on a milling machine. On the right hand side is actually one of my benchtop milling machines, which is an Othermill, now Bantam Tools.

And that's an actual circuit board, which is milled out on that machine. This board over here was actually done on a milling machine as well. Now, there's processes to make circuit boards at home and things like that, but you can see even some of the tolerancing issues that you run into as you start to get into areas over here where the mill has actually over-milled some stuff. Now, if current carrying capacity is a big deal-- because conductors can only carry a certain amount of current-- if current carrying capacity is a big deal then this is one of those areas where over-milling like that can really reduce how much current you can actually carry on a circuit board.

So that being said, we're going to go ahead and jump into the software. But before we do that, I want to kind of highlight just some really basic PCB terminology, which I think will be useful in trying to understand some of the things that I'm going to reference. First of all, let me jump ahead one here.

So on a circuit board, we place components, typically from a library. So all ECAD software uses a library. Again, we buy 100% of the parts that we use.

We place those components down into a design in the schematic. We have what's called a pin. That's the entry point or the connection point for some signal in the design.

And the circuit board, we can call that a pin. Sometimes we do. We certainly do in the context of the actual part itself.

However, on the board itself, we've got an interesting trade-off that has to happen there. The board is purely a layer of copper foil. Certain material is being removed. The part that you buy has to be soldered to that.

And so, the thing that I want to point out here-- and I'll grab my laser pointer just to enable this a little bit better.

AUDIENCE: [INAUDIBLE]

MATT BERGER: Oh, thanks. So the thing that I want to point out here is that the copper foil on the board is actually larger than the geometry of the pin of a circuit board part or a circuit board component. And the reason is is that there has to be a certain amount of solder that can accumulate to hold the pin in place.

So we build a solder fillet. It's a liquefying process, so we're going to liquefy and make molten solder. That molten solder is going to wick up on the tip of the pin. And any time that you look at a circuit board mounted-- or a component mounted on a circuit board, you'll see these large, concave sweeps of solder, usually silver, actually holding the pins in place. So that connection between components, which is made along that path of that copper foil, is actually the interplay between the pin of the part itself and what we call the pad, sometimes called the land, which is the landing area for where those pins make contact with the board.

Now, we can make contact on the board in a couple of ways. We can do that in a surface mount way where a pin has-- or where a part has pins which are bent and make contact with the board along the surface on one side of the board. Or we can have through hole pins. In through hole pins, basically what we do is we drill the holes. Then we plate them. Then you stick the pin in, and we can solder it from the bottom side of the board.

You'll see this with a lot of older electronics particularly. You'll also see this with things that need real good mechanical stability that will actually put holes through the board and allow the pins to travel through the board. So that way those components don't shift around too much. You'll notice this with tabs that hold USB connectors in place, things like that, especially on boards where you're going to plug something in and pull it out a whole bunch-- audio connectors and those sorts of things. We'll see some of that actually later on today.

So we've got a signal path. We call it a track in the circuit board. That's just the connection between one point and another is made using that layer of copper foil. And then connections between layers we typically call a via. And it's just a way of going down through some area of the board and coming out on the opposite side.

So one of the big contributions to the miniaturization of electronics and the availability for us to have things like a laser pointer that fits in something like this was the introduction of surface mount technology, which are components that can sit on one side of the board without any obstructions on the bottom side. And that was largely because now I can put a component in exactly the same spot on the opposite side of the board without the pins poking through, which would prevent me from doing that. When that happened, we got twice the surface area almost overnight.

Now, over time, the process technology has gotten better. So the size of the tracks that connect things together has gone down. The voltages have gone down, and the currents necessary have gone down.

So the current carrying capacity, which is proportionate to the cross-sectional area of the conductor-- you wouldn't use the power for a-- power cables for a lamp to try to jump a car, because 600 cold cranking amps is pretty significant to try to put through a lamp cord. So because our process technology has gotten better because we've moved to surface mount technology, circuit boards have gotten smaller. So now you have a mobile phone. And so, now you have a laser pointer which fits into something like this. Or you've got a key fob, which can turn things on and off, and enable your car doors and those sorts of things.

So as we move through things today, what we're going to do is go ahead and place some components into a schematic. We're going to wire them together in schematic. We'll create the connections, describe the connections. We'll create a circuit board file, and then we'll go ahead and connect the components together in the circuit board file. So we're going to basically take this process step by step through the workflow.

So that being said, enough of the hand-wavy stuff. Let's go ahead and actually get into the software. You should have EAGLE installed and probably open on your computer.

If you don't already have it open on your computer, then my suggestion would be go ahead and open it. You'll find it in the C directory under Windows, which is 8.4.-- it'll be called C EAGLE 8.4.0, something like that. Let me go ahead and jump in here.

When you first open up EAGLE, you'll end up with this. And let me hide the 3D stuff in the background, because it's just too much of a shiny object. You'll end up with the control panel. And the control panel is basically just foundational document handling, library handling.

What's installed? What do I have access to? What am I placing? What am I not placing, et cetera, et cetera?

So inside of the control panel here you've got a couple of different categories. You've got a projects category. And in the book-- which you have available to you right now-- you have a project which is in there-- so went my backpack.

You have a project which is in there for an audio amplifier. It's a relatively simple audio amplifier, but I would encourage you downstairs later today, go and check out the factory. Because we just took people through another workshop actually showing them how to design the schematic, create the printed circuit board.

And right now they're learning how to actually mill out the enclosure and laser cut the actual face of it. But it's a speaker that you can plug an iPhone into. And it works as a fully functioning speaker, taking that process end to end, which has been really fun and exciting to do.

So what you have in that book is an audio amplifier circuit, which taking the relatively small signal which is coming out of something like an iPhone, or a Samsung phone, or something like that and amplifying that so we can drive a speaker with it. Because a speaker is relatively large load as compared to the source.

So in this case, what I'd like you to do is from this control panel here over the projects, navigate down to where it says EAGLE here. Right click on the project-- right click on EAGLE and select New Project. And then in there, we're going to call this workshop. It's going to prompt you for a name. You're going to call it workshop.

Now, the project you should see again under project EAGLE as a subdirectory. We're going to right click on EAGLE, say New Project. It's going to prompt you to type in a name.

I'm going to call it workshop. And you'll notice that you get a little green radio button just to the right of the name workshop there. All that means is is that's the currently active project in EAGLE.

Now to that, I'm going to right click over Workshop. And I'm going to say I want to add a new schematic. We'll do the board later. Don't worry about the board. We're going to do the schematic first.

So in the typical workflow-- if you remember earlier, I showed just that very simple stack. We've got this conceptualization process, which is, hey. What do I want to build?

The next step in that process is to take those ideas and translate them down into a piece of software. And in this case, that involves schematic capture. That involves drawing a schematic.

So this is a blank schematic canvas that we can work in. Schematics can be one or more sheets in size. We can have a schematic which has 250 sheets in it, if we really wanted to.

The truth is is that for most small kitschy desktop type of stuff, I never use more than one sheet. Now, there are some designs where I use lots of sheets. But they tend to be pretty sophisticated, fairly robust designs and the kind of thing that I would do professionally rather than just hanging around the house, though that's not totally true.

If you look at my GitHub repository-- which I'll share the slides after this-- you'll see a ton of my open source stuff. And, yeah, there's a whole mess of multi sheet schematic stuff in there. So maybe none of that is true, and we should just move forward.

So what we want to do is place parts in the schematic and connect them together in interesting ways. That's it. So what we're going to do is we need, first of all, a library of parts to work off of. And the library of parts that we're going to work off of is available already with mechanical models in it, a whole variety of other things.

You have a library menu at the top of your screen. I think it's getting clipped a little bit up there. But if you go to a library and then you go to open library manager, you should see a whole series of different EAGLE libraries available to you.

I'm sorry. I'm Going to remove this one, just so I can follow along with you guys. Play along at home. You should see a whole series of different EAGLE libraries available to you.

So what's contained in the EAGLE library? And the EAGLE library is the schematic version of the part, which is symbolic; the printed circuit board version of the part, which is physical. And then because we've integrated now EAGLE and Fusion 360, there's also a mechanical version of the part, which includes its full three dimensional geometry.

And so, what that means is is I can take a design from schematic into printed circuit board, fabricate the board. But I can also take the board into Fusion, and I can then build an enclosure around it. I can apply constraints to a sketch. I can then go ahead and constrain the sketch according to the enclosure if I wanted to.

When I move the mounting hole, I want the mounting hole to move in EAGLE. We can do those sorts of things. If I wanted to constrain it with a light pipe that's attached to an LED, or if I wanted to add a thermal characteristics to a part and see what the temperature rise is and do some transient temperature simulation or something like that, we can do all of those sorts of things with the integration between EAGLE and Fusion. And that's a bi-directional integration. We can go in both directions.

So here I've got a list of libraries that are currently in use, meaning that they're already installed on my computer. Then I have the list of libraries to the right, which are available libraries.

Now, the manufacturers of parts-- Texas Instruments, Microchip, Maxim-- so a whole variety of different parts manufacturers. The manufacturers of parts will provide a data sheet that has typically the representation for schematic. Somewhere on the last page will be the physical representation, which is for the circuit board, and then sometimes mechanical geometry as well.

Some of those libraries are downloadable, some of them a little less easy to get your hands on. And so, you'll end up having to create libraries.

EAGLE thankfully has a massive community with lots of people eager to teach you how to use EAGLE. So you can find all manner of different tutorials on the Autodesk website on how to build library parts in EAGLE, how to add new components, these sorts of things. But we also have built a pipeline through this system we call the library manager or the managed library system that allows those third party contributors to contribute content independent of our release cycle.

So if Texas Instruments says, hey, we've got a new library of parts and we want to put it in EAGLE, great. Do it, no problem. We can consume that, and you can use that.

So, in this case, the library that we're looking for is under the available tab there. And we're looking for something called audio amplifier. Now, I've got two in my list. Ignore that. That's just because I have one cache locally. I can probably delete that one.

But once I select it, I'm going to choose the option to use. And now it'll shift over to the in use side. That library, because this is a little bit of a contrived scenario-- right, a roomful of people all building the same audio amplifier-- that library is already set up with schematic symbol, printed circuit board footprint, and mechanical model. Otherwise, we would spend a couple of hours building library parts and trying to get those things moving-- so more important that we focus on schematic and PCB.

So I'm going to go ahead and once that thing is in use-- and if it's in use, it should show up in the list here. I can see audio amplifier now under in use here. I'm going to close that. I'm going to expand my schematic here. And then we're going to go ahead and start placing parts.

Now, I think it's about page five-- six or seven inside of the manual that you have there. So, yeah, sorry-- eight and nine. Pages eight and nine-- I talked about adding components to the design. Now, there's a list of components, which are on page nine bottom section there. First, I want to talk just foundational EAGLE stuff-- a couple of things about EAGLE.

Let me grab the mouse here for a second, just so I can play along at home with you guys. A couple of things about EAGLE-- first of all, it is highly modal. Its behavior is very modal.

So what does that mean? What that means is typically in EAGLE you select a command before you do the-- before you select the object. Oh, my HDMI just fell out-- anti-climactic there. Plugging in a mouse and I pull out my video.

So EAGLE is very modal. You select a command before you select the object. So you say, hey, I want to add a part to the design, and then we'll present you with a list of parts. Then you can go ahead and place those components.

If I want to move something, I would select the move command first, and then I would select the object. It's going to feel a little backwards for a while. Eventually you'll understand why it's that way. And you'll say, yeah, OK.

Yeah, there's a lot of scenarios where this makes sense. There are some scenarios where it makes less sense. And it can be a little bit confusing and your brain is not wrapped up for that, but that's OK.

So you've got an option here-- like it says in the manual-- to click the add button. It's just southeast of the trash can. So I'm going to click the Add Button. That should open up a dialog, which shows me all of the libraries which are currently installed.

In there, I've got a library called audio amplifier example. You're going to have to scroll up and down the list. But once you find that library in the list, you should be able to cycle through the various components in that library by just expanding the library here.

And you'll see the schematic symbol, the circuit board footprint, or the circuit board package, which is the area that the part mounts to on the board. So that's where the contacts are on the board-- and then the 3D model that's associated with that part. And we can visualize all of those. If we get far enough today, we can visualize all of those in a way in which we can see them in Fusion.

So we're going to move fairly quickly through the schematic side of things. I'm going to help you to understand procedurally how the things are done, then we're going to move into the PCB. And then I'm going to show you how to export a design, so you can visualize it in 3D and so you can interact with it in the mechanical tools as well.

We will not accomplish everything that's currently in the book today. We have a relatively narrow span of time. But that's why we printed the manuals. We wanted you guys to have something that you can take with you, and you could go through the process of completing the things that are in there as you choose.

So I'm going to go ahead and grab this first part, which is a 90814. If you look on page nine, there's a list of components on the bottom of the page in bold. Next to that, it tells you how many of those parts you need in the design. I'm going to grab that part. And I'm going to go ahead and click OK and just bring it out into the workspace over here.

Now if you right mouse, the part will rotate around the cursor. If you left mouse, it's going to set it down. Don't worry, I can fix almost anything which is broken on-- anything which you do before I get there.

You'll also notice that along the top, you've got a series of different options for mirroring and rotation. So if I decided that I wanted to mirror this part, I could mirror it by selecting one of the commands along the top in that top toolbar. In this case, I'm just going to focus in on getting this part down onto the page. And I want it facing down. You'll understand why in a little bit.

Now I'm going to go ahead and hit Escape. And escape puts me back into the add dialog. So let me try to talk about this from a workflow standpoint for a second.

So the reason why it throws you back into the add dialog is typically when I sit down and think through a circuit, I'll start drawing things out on a white board or something like that. And I've got a pretty good sense of, hey, I need this part, and then this part, and then this part, and then this part. And as I get that series of parts together and queue it up in my head, then I place a part, I bounce back into the dialog.

I grab the next one. I place it. I bounce back into the dialog.

I grab the next one. I place it. And I go through that process iteratively until I get all of the components in the design. Rest assured after we get all the components in the design, we'll start moving things around and connecting them together. What I'd like you to do is just focus first on placing the parts in the design.

So I'm going to grab the next component, which we need one of. If you look at the sheet, it says quantity of one. I'm going to grab this, click OK. And, again, I'm going to add this to the design. And I'm just going to rotate the part around a little bit just to show you that it can be done.

Now, I also need an audio amplifier. So, again, I hit Escape. It puts me back in the add dialog. And I'm just going to run through this list of parts.

The next one is the audio amplifier. I need one of those. If I hit Escape, the next one there is the capacitor. Now, the capacitor I need several of. I think I need five in total.

And how do I know it's a capacitor? Well, I'm an electrical engineer. And I know that two plates separated by a dielectric are a capacitor. So that symbol means capacitor to me.

Now, it helps that it has the name cap underscore ceramic 0805. But, truly, that symbol is enough for me to say, hey. That's a capacitor.

So I'm going to go ahead and grab that. And instead of just hitting escape after the first one, I'm just going to-- 1, 2, 3, 4, 5-- place five of them, one after another. Then I can hit Escape, and I'll get thrown back into the other dialog.

And so, I want to run through that list and get all of those parts down there. You're going to need two of the ferrite beads. Don't worry. We're going to look at the circuit in a second. And I'll explain a little bit about the circuit as well.

So we need two of the ferrite beads. I kind of know where they go. So I'm just [INAUDIBLE] throw a few over on this side somewhere. And go ahead and hit Escape.

Now, you'll notice that there's a subcategory here for LED. And there are three different types of LED listed in that category. I'm picking the 0603 or 0603.

Those trailing numbers for LEDs, or resistors, or capacitors-- 0805 0603-- they mean something to me. It corresponds to the geometry of the package. So 0.3 millimeter by 0.18 millimeter-- or 0.6 millimeter, something like that. That's truly the geometry of that.

So in this case, we're going to go ahead. And I'm going to place that as well. Now I need only one LED. I'm going to drop it down into my design. I need one pin header.

Now, you're sort of disadvantaged to the extent that I know where the parts need to be placed. I need one 0603 resistor.

Now, the confusing thing here-- and the reason why I brought up the LED and the sizing thing-- is that I changed the name of the part since the manual was printed. So you have one resistor, which is RUS 0603 and another one, which is resistor 0805. They're interchangeable.

So RUS0603, we're going to use one of those. And then RUSR0805 is the same as the other 0805. So you need one of the 0603 and three of the 0805.

AUDIENCE: [INAUDIBLE] doing it, what's the [INAUDIBLE]?

MATT BERGER: Sorry.

AUDIENCE: In the book, you talk about they had the symbol. It was a square. [INAUDIBLE].

MATT BERGER: Yeah, so those are actually labels that we're going to apply to name the connections on the sheet. So that's done, but it's not a component.

AUDIENCE: [INAUDIBLE]

MATT BERGER: Oh, we'll get to it. Actually, it should be in there. We talk about adding labels and naming things. It's just not covered probably yet. It's maybe not in the picture that you have there, but it will be. It's covered in the text for sure.

So I want to talk about the schematic for a second. So bear with me for a second. Let me go ahead and open up another version of EAGLE. I don't want you guys to work worry about this.

Now that you've got the components down, go ahead and save your design-- so Control-S, Command-S. Just give it the name workshop. Bear with me for just a quick second while I cheat a little bit here.

So here's another picture of that same design, one that I'd done last night just getting this all straight in my head. And I just want to talk briefly about what this design actually does. And I want to talk about a couple of things which I think are foundational in just understanding how this thing is working here.

So in schematic, we connect things together. We use the term wiring or creating networks of connections, what we call nets. I want to explain what you're looking at.

So, first of all, this is the USB connector in the circuit board. And that USB connector has a power signal coming in and a connection on it we call VCC. Now without getting into too much detail about collector current or any of those other sorts of things, this is an incoming voltage from VBUS. VBUS is a USB signal from the USB standard, which is where power comes in over USB.

A USB port by default on your computer or a USB signal by default can handle or provide 500 milliamps of current, unless it's coming from something like a charger, which can handle more. USB-C ramps that up, which is intended to make it easier to do fast charging of stuff, and try to build things which charge a little bit faster or will allow you to do things like the laptop charging over a USB connection, which is what obviously Apple has done now with the newest version of Macs.

I have ground here as well. GND is just short for ground.

If you think about a battery, a battery has got two leads on it. It's got a positive lead, and it's got a negative lead. The positive lead and the negative lead if I connect a loop through them, they short out.

When they short out, it heats up really fast, and all the power is kind of drained out of it. When I connect in-between power and ground, a series of circuitry, it functions as a load and controls how much power is actually being routed through that particular connection. So what we're doing here is basically creating a closed loop between that voltage and ground.

Now, it doesn't look like that, because this isn't connected to this, isn't connected to this, isn't connected to this explicitly. We haven't drawn a loop. You have to understand that most schematic capture tools or ECAD tools, we've just done that so you wouldn't have a bunch of wires all crossing over each other and trying to figure out then how to read that design.

So as an electrical engineer, I know VCC connected here is the same as VCC connected here. There is a virtual connection in-between these things that I don't really have to think about. As long as I know that's VCC and that's VCC, those two things are connected together, just as this-- which is ground-- is connected to this, which is ground, which is connected to this, which is ground, and this, and this, and this, and this.

So those things are all connected to each other. Everything in here needs a source and a return. If there is a break between the source and the return, we have an open circuit, and it doesn't work.

Now, how we control when power moves between source and return and things like that is how we do things in interesting ways. But every time that an output-- in this case, this is an output. Every time that an output goes high somewhere, the power system has to respond to the needs of the circuit.

We switch things on and off all the time. Those things are changing with relative frequency. But the circuit has to respond to provide instantaneous power-- near instantaneous power anytime that we want to do something.

So, in this case, this is a relatively simple circuit. We've got the USB connection, which is providing power. The two data lines-- d-minus and d-plus for USB-- aren't being used. So we're just using USB just for power.