 It's so easy. I really can do it. Can you see everything? Um, so, are we ready to get started? There's a joke. We're supposed to start with a joke. Why? Because there's an audience to get. If we don't, then the audience will get bored. Yeah! Alright, so let's start with a joke. Oh, I forgot what you told me. There was one. How many programmers does it take to change a light bulb? Zero. That's a hardware problem. Exactly. It's a cube. A cube is a letter with foreign lines behind it. That's so great. I can tell who it is, especially if you're anyone who I've been after first. I'm Leah. I'm in fourth grade. I really like gymnastics. I like to build things with my dad. I'm Chris. I really like watching gymnastics. I like building things with my kids. I work at a company called Radius Networks. We build all the things vegans, and we happen to be hiring at the time and work in this amazing building in Georgetown, DC. And when we talk about full stack there, we talk from rail services all the way down to printing circuit boards. But today, we are going to talk about building stuff. What things do you like to build? Tardises. Okay. How many tardises have we built? Two. Two? Alright. Isn't that a little too many? No. What else should we build? How about another tardis that actually works? You're saying my tardises don't work? Yeah. I think they're just fine. Well, they don't travel in space and time. Fair enough they don't travel in space and time. We're going to need something a little more than an Arduino to make that work. So a little background first. When I was your age, I used to watch these shows on Discovery Channel where they would take students and they would build contractions around a ride and build up a building. And I remember watching these shows and they would talk about that with engineering. And that was basically my reasoning behind going and getting engineering degree. It was because I thought we were going to build paper contractions to throw at some groups. So for a long time I've liked to build things. And I found it a lot of fun that now that I've been doing this and have kids that are doing it along with me, it's just a lot of fun and very rewarding. So we like to build things. And I think this is important. One of the things about building things is it sets you aside from a lot of the other people out there. Do you remember that guy? Oh, why the lucky stuff? Not stuff, it's stiff. I know that doesn't make me make as much sense. But why the lucky stiff? I had a great point. He says, when you don't create things, you become defined by your tastes rather than your ability. Your taste is only narrowing speed, people. So creative. Let's build some stuff, all right? Okay. So we'll build things. That sounds kind of hard. It's going to be hard. You will get stuck. Yeah, I think most people get stuck one time or another. You will need help. I know I need help. You will break things. Have you ever broken anything? Yeah. You won't die. Most people do. Hopefully, it won't be a while. Not related to our projects. Before we talk about that, I want to say a little story. When we think about the worst thing that can happen, back when your mom was in college, she got a car that had one of these, a stick shift. And she didn't know how to drive it. What? No. I know, I'm just surprised at you. Despite how good she is at driving stick now, at the time she couldn't. She went out to a big, empty parking lot, and went way in the back where there was nothing around at all. I had her step out of the clutch, put the car in gear, and I told her to just take her foot off the clutch. And you know what happened? What? The fire? No, the car stalled and she had to restart. And that was it. So that's just kind of like, remember, not much bad things are going to happen. We're going to break things. You cool with that? Yeah. All right. So what's the worst that's going to happen when you wire up all of our shifts for all? You're going to let magic smoke out. That's right. And then you see a little, and the smoke comes out of it, and you have to go by a new working wheel. But that's like, what are those costs? You remember? 20, 30, so? Yeah, it's not too much. That's not a big deal. So you're going to break things. And that's cool. You can do this. You just need to know how to get started. All right. First step. I think one of the first projects you worked on where you just fixed something that was broken. So you remember this thing? Yep. All right. Can you tell everybody what was wrong with it? Well, the car key unlocked the car. The car key did not unlock the car this week. So what did I give you? A screwdriver, a battery and a car key. That's right. And what did you do when you wanted to get started with that? Well, you had to find a little screw, unscrew that. Then you would take off the top to take out the battery. And then you would put in the new battery, put it back on the lid, and screw it back up again. Hopefully that worked. You got it. And if it doesn't work, what was wrong with it? You probably put the battery upside down. Yeah. That is solid trouble shooting advice. Okay. So, are we going to worry about the stuff we're building with? No, it doesn't matter. We have arc tweenones, sparks, tessals, raspberry pies, Edison's, really awesome $400 leg of mine storms. Those are great things, but let's not worry about it. Let's just start with cheap components and just make something work. All right. Let's not worry about what project we're going to build. If you're just getting started, it really doesn't matter. You don't have to be automating your house and building, I think your brother wants to build a robotics room that's a little advanced. So, let's not worry about that. And let's not worry about the tools. So, is this what you're going to start with? No. That's pretty awesome, isn't it? Yeah. Luckily, we don't need an $800 soldering iron to get started. What we used was just a little cheap radio shack soldering iron, which I think would get online for like $8. And that did just fine. So, let's start simple. So, persistence is more important than having the space? Yep. What do I always use to tell you the most important part is? To try hard. Right. And it doesn't really matter. All right. So, the first thing you built was this. What? No. I didn't build that. That looks complicated. Yes. Demandex have a knack for making things look more complicated than they really are. But that is actually what we built the first time. We started with a kid. It was pretty easy to get instructions that were probably translated by somebody who didn't speak English as the first language. Oh, there's another one. Can you tell me what this is? So, this is the use of this machine. So, some of the parts, there are two switch modes. We'll show it to you. Okay. Now, you pull my keyboard. But here's the use of this machine. Okay. So, there's the switch. Here. There's a little motor. So, they all a little work in there. There's another switch. Back there. There is a battery pack. An arm. So, that's it. Can you tell me how or what happens when you flip the switch? When you flip the switch, which turns on the motor, which triggers the switch, which triggers the arm to come up to push the switch, and then it reverses. The motor reverses. So, and then it, then the motor comes down to push the switch to have the arm come down. And then it turns off. Can you explain? I like that. I think the schematic is similar. I'm not sure. You're the only one. I'm sure. What was the most fun about building this, this little project? Probably afterwards, when you got to just play with the trombone. It doesn't do much. Did you get bored with it? Not really. Did you have any problems when you were putting it together? Well, we, um, put the, um, plate on backwards. The mounting plate inside? Yeah. Yeah, we couldn't fit the box together. No. And so we had to take the whole bag apart and put it back together. Yeah. But we figured it out. We built the project, and now we want to move on to controlling, like, working with the microcontroller. I'm going to start with an Arduino. I think a lot of people are familiar with these, a little microcontroller. You can get them for not very much online. And we're going to just turn on an LED. Turning on an LED is totally the hello world of the hardware world. So, the first thing that we did, we decided since we were going to make a project just to turn on an LED, we needed to come up with a whole entire project of ratness. So, we and I do what we and I do, which is we built a TARDIS. This was your Halloween costume last year. Well, my brother is developing a costume last year. Yeah, because he was which one? He was the TARDIS. That's right. And you were? The doctor. Which one? Management. Which is your favorite doctor? Management. Oh, sure. And being a highly trained professional programmer with degrees in computer engineering, I did what you would expect me to do. And I Googled for an Arduino sketch that I have pasted into the little ID. And all this does is step up the power that's going to the LED so it fades in and out into the light on the top of the TARDIS, which fades in and out. Which worked amazingly well when we were trying to treat it and walking down a dark room. So, if we could turn on an LED, now we want to control a relay. Can you tell everyone what a relay does? So, a relay is anything that you could turn on with a switch. Yeah, a relay is basically a switch that a computer can control. And it can feel around you like everything has a switch. Remember the buttons as well. Everything has a switch. So what can we control with our computer? We can control everything. Right. So, we start playing with the relays and we're using a Raspberry Pi. And we use a little gem out there called PyPacre. So this is all the code we need in order to get a relay to flip one off. But what about controlling the computer? Oh, if you want to control the computer and everything around it. Well, then we need to detect the button press. So, if you want to detect a button press, this is us turning the computer or something, not the computer controlling other things. So, we can get to push buttons? We can get to push buttons. It turns out, hey look, it's installing. It turns out that this is all the code we need. We're just going to set up a block and watch a pin. One of the pins on the Raspberry Pi. And when it changes, you get a callback and you can find out what the last value was and what the current value was. Now, this is a little over-simplified. If you're going to set up a Raspberry Pi to detect button presses, you will also need something that's going to start your script. But in a minute, you'll have all the different moving parts of Linux. You'll need something to launch it and make sure you can load your gem and this sort of thing. But once you get all that working together, you only need these four lines of code to get it to work. So what if we built down that we have a button and a relay and Linux and its scripts and all that working? We've built a light switch. Yes, we've essentially built a light switch. That was easy. Yeah. Okay, so let's talk about some of the big scary barriers. The thing is that people find intimidating about when we're working with hardware projects. Were you scared of soldering when you first did it? A little. A little? Is it that bad now that you know how? No, I'm not scared of soldering. So we're scared of programming and screwdrivers. What's going to happen if they're carrying a soldering iron? What could possibly go wrong? Let's give them a quick couple of steps for when you live with a soldering iron. What you need to do and then we'll show everyone how to do it. Okay, step one. Get all of your stuff and plug in the soldering iron. Yep. Step two. Prepare the soldering iron. Step three. Keep the components. Interesting. I didn't quite have the guts to ask the organizers if we could have toxic metals and a toxic gas. So we're not going to actually do this, but maybe I can walk through a walk through of how it works. Okay. So first, we have to tin the soldering iron. So you take the solder and touch it to the tip of the solder. Then you can wipe off any extra solder. Sometimes you can zap off because this doesn't work well. Sometimes you have to dip it a bunch. Get it off. Then you heat the component. Then you would put on the solder on the other side of the component and hold it there for about a second. It should run around. And one thing is don't heat the solder or the solder because then because the solder will shrink and that will work out very well. And these are the ones that you actually did our thing. Yeah. So being a highly tuned professional engineer and despite the amazing demo, you should do what I did to learn the solder which is watching YouTube. There's not much to it. The main trick is learn to keep the component. You'll watch the solder wig right in the place if everything is working right. You shouldn't be fighting with it or trying to get it to stay. Anything like that. There's great guides online. I like the way on a website called SparkFun and it'll show you a couple guides and give you some references on what the solder should look like when you've got it right. And as long as everything is heating up it just kind of wants to work for you. So it's not it's not that bad. So let's let's go through a couple of reminders. Let's recap a few things. You can do this you just have to learn how. Is learning it that hard? No. We have like a whole internet chart which teaches how to do these things. It won't be easy. That's what makes it awesome. It's easier if you start small. Easier. Not easy. Alright. That's what really is the fun part about this. They get something that you know that a lot of people would have tried and just kind of given up and put the what do we know and the closet won't worry about it ever again. Alright. So thanks. But before we go we have a couple of quick things that we'd like to mention. Firstly I was going to give her a plug or Okay. So I got it to the one day to show you some. We really like it there. So any little guys that want to do gymnastics is a good place to go. Yeah. If you have little guys that want to do gymnastics this is a good place to go. We really like that. Another thing is I'm going to help organize a conference called We For Good where we have a multiple day hackathon for benevolent projects mostly nonprofits holding source that sort of thing. There's we work on a lot of awesome projects including the things like the Humane Society Purple Door people were hacking on our spec and other open source things and everybody gets together and we have a great time. This year it's going to be at the Smithsonian George Mason wildlife instructor it's what it's called in the front world Virginia and I think there's one thing that you should think about if when you're going to pick which conferences you're going to next year is just ask yourself one question and it is will there be red hands? and finally so if anybody wants stickers or wants to trade Leah's trying to take how many of the stickers would you like to get? all of them all the stickers so she's trying to get all the stickers which would be very impressive coming off of RubyConf so if you'd like to trade Leah has stickers then we'll be happy to trade alright thank you when you started using the soldering iron was machine a kit or from scratch? it was a kit I think it was like $30 at Micro Center what's your favorite thing you've built so far? from the useless machine when you ask your friends or you tell your friends that you've built the useless machine and they believe you some of them is it not all of them? yeah but when I brought it into the share once they actually saw it yeah so the question was I use Pipe Piper when I'm working with Raspberry Pi do I use other gems with the Arduino? yeah I've used Arten and they have a firmware called Formata that you can load on it and it'll basically give you an API and that's great as long as you have a computer it's still required the computer to kind of talk to it to host the Ruby often I'll do that with the Raspberry Pi running the Ruby that talks to our everyone yeah how do we come up with the ideas for our projects? well some of them so for these this machine my dad was online looking for a kit for us to do and that was one and with my mom's car keys they come to finding stuff to fix and also it's just hanging around and chatting with Leanne and her brother and finding things that'll be fun for them the things that they want to do have you thought of combining your love of building things with your love of gymnastics? no no no you should what is the next thing you want to build? um well besides a TARDIS um I want to build a gymnastics yeah I've always wanted to do that what did the TARDIS do and how did they work? okay so one was the Halloween costume um well um my brother he sort of had to um like move it but um it says the bed but he built a Murphy bed that looks like a TARDIS in the guest room and it works as a bed but that's not as fun as traveling in time and space? yeah turn