 Thanks for coming to one of the first talks. And sorry for some technical hiccups there, way PowerPoint. So way back I used to stick LEDs onto celebrities for a job, here are some of them. And it was a lot of fun, but it didn't really pay much, so I went back to more ordinary stuff. But in 2017 I decided that I was going to go to Burning Man for the first time. I definitely recommend it. It's not for everyone, but I had a great time. And I thought, well, Burning Man, you kind of need some wearable blinky because at night, unlike EMF camp, you can't really light the whole site because it's miles and miles across. And people are cycling and driving and there are drunk people and other kinds of people. So most people just wrap some EL wire around themselves or some LED tape or something or they stick it onto their bicycle. But I thought, nah, come on, I'm a pro at this stuff. I should really flex hard here, maybe attract a bit of attention to myself. I like being the center of attention from time to time, not all the time. And also by coincidence, oops, I happen to be camping with these people. These are the flaming lotus girls and they're probably the world's best known fire art collective. They're in San Francisco. Just Google them, they make incredible sculptures. This thing is, I mean, you can see it's huge, but in reality it's absolutely ludicrous. It launches these jets of burning alcohol into the sky, something like 30 meters straight up. And I thought, well, if I'm camping with them, I'm kind of bored of LEDs on people now, maybe I should put fire on myself. And that's what I did. So safety third, that's what they say at Burning Man. Safety is obviously, if you're wearing something like this, it's got to be safe. But if it was old for safety, you'd never build it, right? So that's the kind of immediacy that's at Burning Man. But this thing contains a billion safety features, but I don't want to make the talk about that. So if you're curious about how this is actually practical and how you actually might take something like this to a festival, yeah, talk to me about that. But you've got to think about three things. You've got to think about safety to yourself, safety to others, and even safety to the event, like legal safety or all that boring kind of insurance stuff. You don't want to create, you don't want to bring some super janky bit of flaming electronics or whatever to a festival, even if it works perfectly and doesn't hurt anyone. So my slides are slightly out of order because things. So this should say, oh yeah, it does say ingredients. Right, so hang on, wait, I was going to tell you the specification. The main thing I wanted was, oh wait, I left my notes at the side of the stage. Hang on a minute. Sorry about this. If I move suddenly, so you'll notice if I'm moving very rapidly, then my hat will not fire because that's unsafe, right? So there we go. I'm happy I left those notes at the side of the stage now. Yeah, so I just wanted to tell you a little bit about what I was aiming to do. So I wanted to make a fashion accessory because it's in a desert, right, burning man? You saw that picture. The desert is very hot in the day, so you want to wear almost nothing, and it's extremely cold at night, so you want to wear all of the things. And I wanted something, given the amount of engineering that would have to go in, I wanted to have 100% uptime and it to be a practical fashion accessory, so a hat seemed like the obvious way to go. What else? Yeah, hours of autonomy was a big deal because the campsites are so far apart, so I wanted this thing to run for at least two or three hours, not require a lot of love and attention, and I wanted to be able to refill it instantly, so I wanted batteries you could swap out, fuel you could swap out, and so I was really giving myself a huge shopping list of pain. I had about five weeks left, and the concept was just a hat that's on fire the whole time, right? That's pretty straightforward, it's conceptually, you just have to deliver some flame to the atmosphere and set it on light, job done, make it safe. But I did the sums and I made all sorts of prototypes and it was just not possible at all. Just the amount of fuel consumption was just astronomical, I could have done it maybe with liquid fuel, but that's really dangerous, so I thought okay, it has to be a poofa, it has to be something like this which stores up a bit of gas and then bam, and it's all about making the most bam out of the tiniest mass of gas possible, so each of these poofs is a mere 20 milligrams of gas butane, and it's rather than just burned, it's almost detonated, so it's instantaneously released into the atmosphere and ignited at just the right point, so you get a little kind of mini boom rather than just a kind of flamey jet, and obviously that multiplied everything by a factor of a million, so yeah, took up a lot of love, but yeah, I had a great time building it, so what else do I want to tell you? So yeah, ingredients of fire art, so I'm going to go through all the bits that are in the hat, kind of from the input to the output, and I'm going to draw some connections to electronics because that's probably what people in the audience might be a bit more familiar with, so at the beginning obviously there's a gas cartridge of some kind, I'll just mention a little bit about this, you can see that cartridge I've drawn there, there's some gas at the salt and there's some liquid at the bottom, and they're in equilibrium, and they're at pressure of course, and they're at the vapor pressure of the gas, and that's just a chemical property of the gas which varies with temperature, so if you increase the temperature more of that liquid will boil and you'll get more gas at the top under more pressure, and conversely if it cools down go the other way, and the reason I mentioned that is that this is a key part of fire art is that you have to remember that your gas is constantly boiling which means that it's constantly absorbing heat because boiling is an endothermic process right, so to keep it boiling it needs to draw heat in from the environment, so you have to make sure that your cartridge is getting enough heat from the air that your fire art isn't going to get all sad and floppy, so that was the one I picked, you've probably seen these around the campsite, these good because you can lay them down which is great for a top hat where they just fit perfectly, so I got lucky with that, you can see a little L-shaped pipe there so that ensures that when the cylinder's on its side it still feeds gas rather than liquid, if you take a normal camp cylinder and put it on its side you get liquid which is more dangerous and harder to deal with, so that is another reason to choose those, valves right, so I was going to say the analogy right, so the analogy for a gas cylinder, that's not like your battery right, that's what your energy comes from, both chemical energy but also mechanical energy, another advantage of using gas is it doesn't need pumping right, it pumps itself rather than liquid you have to kind of push it along with the pump so that's another reason to go with gas, so valves they're kind of like the switches and if you want to make micro fire art like this I recommend looking at camp stoves and plumbing tools and kind of nicking and swapping bits from those and I use the valve from one of these as my isolation valve at the front here so this allows me to cut the gas very quickly, solenoid valves are kind of taking that to the next level, so this is really where the rubber meets the road, this is the fun part where your software can interact with your gas and these are just like a relay in electronics, so you've got a coil just like a relay, energize the coil, gas can flow, orifice, no giggling at the back there, these are a bit like a resistor so when you flow current through them it restricts the current flow and it builds up a pressure differential just like you get a voltage difference in electronics and they're really handy, they like sticking your thumb on the end of a hose, you can increase the velocity by slowing down the actual amount of flow and they're used in a couple of places in my hat. This is an accumulator, it's kind of like a capacitor in electronics, you can put some gas in it and store that gas and store it under pressure so it's got energy available for use and you can fill it up slowly and release it quickly which is what I'm doing here, now I didn't really have a good picture because they're very generic looking so I put a lot of people in fire art use off-the-shelf propane cylinders that are normally used to store gas, you just not take the valve off the top and you can use it as a accumulator like this. Pressure gauges, I use these a lot for debugging, they're really cheap and easy to work with, they're kind of like the voltmeter of the gas world, they tell you how much potential energy is available, how much pressure is available, pressure is kind of like voltage you can think about it and flow is kind of like current so if you know about electronics kind of having that in the back of your mind kind of starts to help you draw connections. Pressure transducer, this is again kind of like a voltmeter but instead of outputting that voltage on a needle, sorry that measurement on a needle, it outputs it electrically so again this is cool because it's another bridge between your software, your electronics and your gas system so yeah these things are fantastic, this is the one that I actually used in the hat, this is from Honeywell. Pressure regulators, a bit more arcane, anyone know what this might be like in electronics? Yeah! Voltage regulator, right? LM317, classic, so the pressure regulator or voltage regulator takes a high pressure or voltage in and it can be variable, flailing all over the place and it drops it down to a constant voltage out or constant pressure out in this case, so very very similar devices and I tried to avoid using them in the hat because they're enormous, there's no market it seems for high pressure, tiny wearable voltage, wearable pressure meters, right? So anyone who's looking for the next startup, I will be your first customer, I had to actually make this one from scratch, there was no way around it, I had two days left before I was going on a plane to Burning Man and I discovered that I had to make a pressure regulator and it worked, I made it out of a Schrader valve from a bicycle inner tube and some machine components and there's this little piston and the piston gets pushed to the right hand side, I can't flip that around, pushed one way against the spring and the spring sets that output voltage, so if the pressure drops the spring pushes the piston one way that lets more gas in, gas flows in, builds up the pressure, pushes the piston back against the spring, so there's a closed loop spring going one way, piston going the other way against the gas and that gives you a nice pretty steady output and that's in my ignition system so any scientist in the audience? Yeah, you must use one of these daily, right? That's not what they told me at school, I thought I had transferable skills. So this is a classic example of a Venturi, right? So Venturi is where you again narrow the flow to a condition called choked flow where the gas is just going as fast as it possibly can, which is the speed of sound in the gas, so the gas is going out of that nozzle really, really quickly and that pressure differential I measured, I mentioned, that can be used to suck in another fluid, so in this case there's a stream of propane or butane in my case spraying out really high speed and it sucks in air around it through the holes around the bottom of the burner, around the Bunsen thingamajig where you can twiddle it to adjust it and that draws in air, it mixes the two together in that tube and then out of the top instead of like a lame wobbly like yellowy flame, you get a good powerful jet flame and that's obviously important, you'll see in a minute. So let's put it together right, so this is the hat. I won't go through all of it, I'm not sure how much time I have, how much time do I have? Ten minutes, okay, well I'll go through it very quickly. I'm going to point with a stick now without changing slides, so, oh, it's alright. And look, anyone in the front row? No, it's alright, I can't, can't burn you, right? So, I'm going to go around here, does that work? I'll just turn the, tell you what I'll do, I'll just stop pooping for a second. There's a lot of things to think about here. Hang on. Oh, I just put it on super poop mode, wait a minute. Okay, yeah, there you go, kind of, kind of. If it runs for too long, because of that vapor pressure, if it's a cold day, it doesn't have the full pressure, oh, hang on, if it's been running for, yeah, thank you. If it's been running for a long time in a cold-ish environment, then the vapor pressure in the cylinder drops and it can't hit its desired poof level. So, there's a menu system, there are like four poof levels, maybe I'll demo it in the end if I have time, or you can see me after the thing. But, yeah, anyway, I was going to point at this thing. So, yes, if there's not sufficient vapor pressure, your artwork gets sad, so you have to kind of think about that and maybe sort of think about how you use your gas and when and how. So, everything in blue is electronics and therefore boring. So, we're going to look at the gas stuff, right? So, gas cartridge goes in, so that's your battery, right? Connector, connects it to the system, then we've got an isolation valve, this is a screw gate valve that I took from a primus stove, cam stove, I don't know why it's jiggling, but never mind the frame. So, that can cut off the gas supply very quickly, so it's nice and safe. Then there's an orifice plate, so that limits the flow rate in, because the flow rate might be massive if the gas's pressure is really high, or it might be really slow. So, this orifice just gives you like an upper limit on how quickly gas is going to flow into the system. Gas then flows into this solenoid valve and if the software is happy about it, it turns on the valve. So, that's going to start poofing. So, you might even be able to hear a click. Can you hear that click? Yeah. So, that's that guy. That lets in gas, that goes up into this accumulator, builds up pressure in there. The pressure transducer is waiting for that 20mg of gas to accumulate. So, it's waiting for the pressure to ramp up. It assumes the temperature's kind of roughly constant. So, when there's 20mg in there, this one closes. So, that's ready to go. Meanwhile, a little bit of gas has been escaping down here. No, sorry. A little bit of gas has been escaping this way. Got lost in my own diagram there. Sorry about that. Through this thing. So, this is the pressure regulator, the nightmarish thing that I had to build. That is limiting the pressure that goes into the Bunsen burner, essentially. There's like a tiny Bunsen burner here. So, there's a venturi that creates that gas drawing in effect. So, that's the air here getting drawn in, mixed with the gas and you get this nice jet. You know, like those jet sort of cigarette lighters with the blue flame. It's exactly like, in fact, it is one of those. So, that's that. Gas flows in there. So, you've got this little flame going all the time waiting, well, all the time this valve's open. So, when the accumulator is ready and the pressure transducer says, then the software closes that valve, dumps that valve, opens that valve, rather, and dumps all of that gas instantly into the burner. So, that's like a capacitor. It's been like slowly ramped up in charge and then, boom, all of that charge is dumped through the solenoid valve, through this venturi, which draws in air to make the actual big poof flammable. And then everything mixes together, gets lit by the jet. Also, at some point, there's a spark which comes out of this high voltage generator. The spark ignites the little bounce and flame. I probably should have practiced this bit. And then everything comes together. A spark, flame and gas and you get a poof. Thank you. Okay, right. So, what's next? So, I think we're going to click through a couple of close-up views. Sorry, these are not edited very nicely. But this is kind of the general view. This is like the cyberpunk side of the hat. And this is the kind of steampunk side, obviously cooler. And here, I think, I might point again. So, this is where I might ask you very kindly to do some left, right, left, right. Okay, great. Thank you. So, I'm just going to very quickly go through that again in more concrete terms, right? So, you can see what all the individual bits look like. So, this is the overview. Next slide, please. So, here's the input. So, this is a little tap, the valve that I stole from the Primus thing. There's the butane cylinder there. That's the accumulator there. Next slide, please. That's from the back. So, you can see it's all nicely packed in. Again, that's the accumulator. And here's this output tube. You see it's like quite fat. So, it's got enough cross-section to get that really quick flow in. Up here, you can see this venturi here. So, that gas is going to fly really super high velocity out here. And those holes there allow air in. So, that's where the mixing happens. Next slide, please. Click. This is the cyberpunk size. Very briefly, it's a micro-python board, a relay thing module from Amazon, a DC-DC to go from 5 volts to 24 volts for the valves. A high voltage generator stolen from one of those jet cigarette, no, no, like the rechargeable, has anyone seen those rechargeable plasma cigarette light? It's like an X-shaped plasma thing. They're really cool. So, they don't need any fuel other than USB fuel. So, that's one of those stripped down. And then the spark goes up this high voltage cable that's also got woven fiberglass around it so it doesn't get burnt. Next, here are the solenoid valves. They take up the most space. So, I really wanted to have a third one controlling the pilot light, but it just wouldn't fit anywhere. So, that's what led to the whole adventure with the pressure regulator and all that stuff. Next, oh, actually, no, sorry, get back, please. Yeah, there's the pressure transducer, right? So, that thing's got the electrical input there, gas input there, and it can just convert gas pressure to voltage. Very convenient. That's my little regulator there. So, there's the sliding element inside. Spring here, little screw here, you can adjust the spring pressure, which adjusts the gas pressure. And then there's this little connector here. So, I can take the whole top deck off if I need to, and unplug it here. Cool. Okay, next. Okay, there's a slow-mo video. Actually, maybe just go back, please. Will that restart? Yeah. So, just when I say next, hang on a second, just look at how that pilot flame starts to burn, right? So, it's going to be about here. Ready? Okay, next. So, there's a little spark, and then it comes out like that. And then some seconds past. This is really long. I wanted to edit out the middle bit. So, let's just pretend it's not happening. But what it's doing at the moment is it's charging up that accumulator with gas, and it's waiting for that special brush. There we go. It's coming out. Cool. How much longer do I have? How many more minutes? Three? Keep going. Three, two, one. Okay. So, what I'll do now is I'll show you a couple, like one more feature of the hat. And maybe, gentlemen, I'm so sorry I didn't get your name. I forgot your name. Cool. Can you just flop back and forth? I tried to make it loop, but I failed. So, maybe you can loop it again. When you see it stop, just go back to the beginning and get forwards again, if you don't mind. Just go left or the right. That'll give me a couple of minutes to just warm up this cylinder. So, we're going to do a science experiment now, right? So, a bit of science. This is how much flame we've got at the moment. If I put it on super, that's super. Yeah, yeah, yeah. If it's really still, you get smoke rings. So, super poof mode. Just again. Hang on. That's ordinary. This is super. It's getting there. It's thinking. And that means, oh, I couldn't do it because you've asked too much of me. I asked for, I think it's for the 200 kilopascals is what I'm asking for when I press that button. And it can't manage it because it's too cold. So, I've got a hairdryer. So, while I fetch the hairdryer, okay, we're coming back on stage. On the stage, I think, would be good. If there's a plug somewhere. I was told there was one somewhere. I should have done this before, but it was hectic. Yeah, by the laptop. Oh, yeah, done there. It's great. Okay, cool. So, I'm going to take off the hat. It has a, oh, yeah, just off for now. Thanks. That was wonderful. Just lay it down, please. So, I have a strap underneath for cycle safety, which for real, because a burning man, everybody cycles. So, I wanted to be able to wear it cycling, and indeed I did, but the main reason for it is to stop drunk people wrestling the hat off your head. So, also important. So, I'm going to take the cylinder out. Okay, I don't want to hairdryer the microphone. So, bear with. So, we're just going to heat this up to about 30 degrees. And that'll give you a kind of view of what's possible in wearable fire. Last time we did this was at Hacker Hotel. Demetriu there representing fire. In fact, are there any other fire artists in the room? There's one. Demetriu is a fire artist. Anyone do like fire poi or juggling? Yeah, yeah, yeah. Fire breathing? Any fire breathers in the room? Yeah, excellent. Yeah, I'm too scared for all of that stuff. So, I had to outsource it to my hat. Okay, cool. So, that's now like, maybe, maybe 15 degrees. I don't want to keep you waiting forever. I forgot to open the isolation valve. Okay, so, super. Sorry, that's an ordinary poof, I think. So, ordinary poofs, super, right? So, now, give it a little jiggle as well. Oh, anti-climax. If it's too quick, if it's too much fresh, sometimes it blows out the pilot flame. That's why the, oh, no, guys, come on. That's why the little pressure regulator had to exist in the end, because sometimes that pilot flame blows itself out. Yeah, we go. Cool.