 Okay, so you're here for the Lightning Talks and you've got Melanie on first with a zero knowledge, and I really hope you like Michael Cain Hello Hi, so my name is Mal. I Mostly do product security and I spend six months during the pandemic researching about your knowledge protocols so your knowledge is a Protocol it's a sort of protocols for encryption and The best way I can explain it is by giving you an analogy. So Imagine Stigman Bruce trying to enter his house and normally he has his keys because this is house But this time well this time Michael Cain well, sorry Alfred has the keys and The only way for Stigman Bruce to enter his house, which is not the way in manner is the power puff girls house for some reason Alfred has to ask him a set of questions to prove that he is indeed Bruce so questions could be like What year did you buy your sofa or what's in the cupboard of your kitchen? So only things that Bruce would know because it's his house so There's two types of zero knowledge one is the interactive one so interactive your knowledge refers to a way of authenticating or Verifying someone's identity in this case Bruce by sending a request and every single request Is gonna have a challenge immediately after sending that request so imagine one of the proofs that Bruce is gonna give is that he bought some facility With this Tesco card on the 26th of November of 2021 and Alfred is gonna be very interested to hear more about that Every time he goes through the list of the shop The other type of sheer knowledge is non-interactive So in this case the challenges and requests are processed in a batch. So instead of Stigman Bruce giving him a list of what items were he's just gonna hand him an encrypted grocery list From Tesco's and Alfred is gonna be also very interested in hearing and reading that So in order for Protocol an encryption protocol to be classified as zero knowledge. It has to abide to three properties one of them is completeness so Every single step has to be complied Bruce has to verify and answer every single question that Alfred is gonna ask him Rationality so if Bruce were to make a mistake just once that Break zero knowledge and that is gonna prove a fail and it's gonna be disregarded. The final one is zero knowledge Which is the whole point of these protocol suites, which is the only information that Alfred can have is that That is the person itself He can only believe that the person is who they say they are But they cannot know any sort of person personal information in this case Passwords or anything like that. So if we translate this chaotic analogy Whenever a serial protocol The way serial protocols work is that you're gonna have a prover and a verifier So and this gives a prover is gonna be Bruce and the verifier is gonna be Alfred and This going a bit more technical imagine you have a password and you're authenticating with the service Where you're gonna do is you're gonna create a signature of that password So that a hash of that password and you're gonna send that hash to the server or the verifier or Alfred Alfred is gonna grab that hash Alfred is gonna create a signature with that hash is gonna sign it as well And it's gonna send back that signature to Bruce this could be a public key for example and then Alfred is gonna store that hash and it's gonna send a random token signed With the service signature offer signature and it's gonna send it back to Bruce Bruce is gonna then prove that it can sign that signature and send it back to Alfred and Alfred is gonna like perform some calculations to check that The the contents the hash has been signed with the signature that he shared So the whole point here is that there's never a password being sent or stored anywhere It's always gonna be a signature of a password or a hash of a password or a signed hash Nobody's ever knowing the server is never knowing what the contents of the password actually is and Not trying to go very technical here, but One way Sierra knowledge protocols do this is by using something called elliptic curves So the way a server or Alfred would create these random tokens or signatures They could use elliptic curves So the way this would work is Bruce would send the hash password to Alfred Alfred would put That hash password into our point generator that is gonna give an X and Y point that is gonna go on an elliptic curve and That way is gonna verify from the subsequent challenges or attempts of Authenticating if the hash does indeed Generate the same point in the curve and that's a good way of like verifying for this My research mostly involved possible applications of Sierra knowledge and one of them was using single sign-on authentication For those of you who don't know like single sign-on is we use it every day And it's for example when you want to log in to An application using your Gmail account and you select signing in with Google or you're using things like octa signing so I was researching The way you do single sign-on usually is with SAML for large enterprises So I was researching into re-architecting the whole SAML flow by adding a step where instead of Verifying the password you would verify the hash of a password and you would involve a more serial knowledge architecture to it I Found out in a in a survey. I did that most people would be happy to not have to Input their password every single time but the challenges with this sort of applications is that to compute those calculations with the elliptic curves It takes a long time so As of now it would take about a minute with the Research I've done to sort of compute without having to start your password, which is not great and The whole concept of Sierra all finished with the whole concept of serial knowledge was actually from the 80s But it was sort of science fiction at the time because we didn't have the computing power to perform Such calculations and nowadays we're sort of getting closer to Serial knowledge so it could potentially be the future for authentication without passwords and That's Michael Cain. Okay, one speaker presses the buttons for the next speaker. You can hear me. That's great Okay, so next up we have adventures in cosplay with Clermont Holland and I think you'll find it. It's a real oh a Real breast of the wild however the slides have just disappeared somebody press the right button. Oh Yes Welcome everyone and I am here to talk about making this And yes, it was quite an adventure next slide please So from the beginning it took a long time to figure out what shapes I was actually wanting to to design here and The sword itself comes in different layers. I'm not sure if you can see that very well But it the design process took quite a while to figure out what I actually wanted to laser cut And this has been made out of Kind of a very transparent acrylic but next slide please The process of laser cutting it Let's just say there was a lot of burnt wood a lot of burnt wood that took a number of attempts But yes Eventually we got something that would slot together as you can see here This is very good at pointing actually as you can see here There are little holes cut out in each of the layers because there's screws That go the whole way through and is actually what keeps it together But there's ten of them and every time I have to change the battery or something breaks I have to unscrew all of them So if we go to the next slide Here you can see all of the pieces. There's a lot These ones needed glued together. It was a long process And the shield itself this also took quite a while, but the sword is the pain here So yes sword lots of pieces next slide We had some tests as well with cardboard because we only had so much acrylic here didn't want to waste that but thankfully we did get a Working model here. I kind of I kind of like it with the wood, but Link sword is blue slash purple. So we couldn't keep it. It did smell quite nice Parkwood is quite nice, but anyway next slide please Here you can see it assembled get again ten screws ten screws and is is important to note also that there is a A battery pack in the hilt here. It takes up about 75% wasn't a good idea but next slide Here you can see the Shield which we decided to do out of clear acrylic that was then spray painted On the back so that it could be waterproof So each of these pieces spray painted individually and then screwed on to the wood Which was cut in two pieces and it made that These straps are really not good for skin. So Well, we make do Next slide Here is the electronics phase Sorry, I keep forgetting about this it Did not go well originally safe to say Last time I did soldering was about four years before this I Didn't realize that you're supposed to keep the pin separate, but it's fine My brother then told me that's why it's not working But yes, there's a double-sided LED strip as you can probably tell the whole way up the blade itself that is then attached to a Trinket in the hilt or in the 25% of the hilt that's still left And then the rest is just wires. It's just wires. It's a complete mess in there, but it works That's what's important here. Always remember regardless of your project as long as it works at the end You've made it. That's all that matters But yes, and I think there's only one more slide Yes, so as you can see finished product I would still probably do this again. There's still parts I would improve upon mainly The the hilt of the sword is massive. I have small hands No, not the best idea, but yet again the battery pack is huge. So we had to fit it in there somehow But yes Marl of the story make things. It's great with highly recommend As with all the speakers, I think they'll be hanging around at the end So if you need to ask them any questions, then at least Claire's really easy to find Do we have Casper in the room? Yes, so next up is Casper This talk does contain the word flange, which I find really like hilarious I don't know why I love the word flange, but there is the word flange in that it's on one of your slides I've been looking would you like this microphone or that microphone? Five I'm pretty sure Thanks So my name is Casper and I'm here to talk about kitspace.org which is a website to share electronics projects that I created It looks a bit like this just lots and lots of PCBs all kinds of stuff Just kind of decorative stuff since NASA has a project on it. It's a hobby rover, but Yeah, that's kind of what the website looks like when you go into a page you get links to order the PCBs so you can click on one of these sponsor links and it goes directly into the PCB batching service website or you can compare prices or you can just download the Gerber files and send them wherever you like You get a preview of the board You can click on this assembly guide that works for KaiCAD and Eagle projects, and it gives you a I wish I had a picture of that. I should have done a slide of that, but Interactive interactivity go through the PCB and each component and it shows you where to place it so it's good for hand soldering and You can just inspect the Gerber files as well on another Website to go through to see if everything looks right There's below that there's links to buy the parts So that's some of the automation I built you just click on if especially if it's a green link like that You can click on the digikey link and that puts all the parts you need for that project into your digikey shopping site or any of these other Distributors you can go through the bill of materials and it shows you all the information you need on each component as long as the The person that's put the project up has a put all that information in there Not not like the retrieved information, but just the basic part information and from that we can get further information We can get the data sheet. We can get all the specs of the components then below that you'll find a read me and that's Kind of typical for a project to just where the crater explains more about it It's the website itself. It's all open source. So you can go and get up comm slash kids base where? The kids base is the current website. We're working on version 2 which is integrating Getty, which is an open-source GitHub clone. We're integrating that as the back end and we're currently working on that We've got a few other things interesting that might be interesting to you to if you're into electronics We have some we've been collecting chi-cat footprints. We have a kind of a nice Awesome electronics is called just a list of resources that are Interesting if you're into electronics or want to get into electronics Yeah So one of the things that I've been working on as sort of part of this is the some standardization efforts Together with what's called the internet of production alliance So we're trying to figure out can we standardize below materials part information and all of that and and come up with a Better way to make electronics that makes it more repairable and reusable down the line And that's available at this link if you want to know more about that That's in the earlier stages. So we love to talk to people about that what kind of ideas that have How a standard could help in that area? So that's really my talk. I don't know how I'm doing on time But these are the important links check it out on on get up comm slash kids base or check out the standard Always open to contributions always open to people putting their projects up. So thanks very much. Oh I have free PCB rulers and stickers if anyone is interested in that Wonderful nice easy Web link to to remember kit space. It's a space with kits on Thank you. Okay. I Put my notes down somewhere, but Kate is up next So we be using this microphone Excellent. So The people mover and why Elon Musk can suck it. We're actually not going to talk that much about Elon Musk because he sucks Oh, no, wait, which button do I push to go down? right Yes, so my brother lives in Las Vegas and in Las Vegas you now have the Las Vegas convention center loop. We're just supposed to be this amazing Public transportation system of the future where you can go from one end of the convention center to the other at two minutes Right fantastic sounding right? You know what it is? It's a bunch of Teslas in a tunnel It's it's tunnels. Oh Tunnels operational tunnels will go to the airport in a tunnel Yeah, you know what happens when you have a bunch of cars in a tunnel even if they're electric cars traffic Traffic jams you got traffic jams in a damn tunnel you get traffic jams on the road above and There were Teslas, so you know they'll catch fire and then you can't get out because you can't figure out the doors Because you're not a tech person. You're at the International Proctologist convention. What do you know? So you die in a fire and the reason why it sucks the most is because it is not the people mover The people mover was a transportation system that was installed in 1967. I want to make that clear 67 it gave you a tour around Tomorrowland in Disneyland. It had linear induction motors They make the wheel they make tires turn which push the cars around and The cars constantly move There's no traffic because they're still going all the time and you go from a moving platform To a moving car, so you don't even have to stop the cars at any time to let people on and off It's based on this amazing They have amazing names because it was the 50s when they did it the Carvayer system The speedwalk speed ramp Carvayer system developed by Goodyear and Stephen Adams Manufacturing this is one of their patent pictures that they did for it It's was for they were gonna do this great big system in the In New York and it was gonna go from Grand Central Station to all the hot spots in New York And you see they've got the conveyor belt They've got the little moving cars Everything keeps on moving along perfectly whoosh whoosh whoosh whoosh whoosh no traffic no stopping Nothing and also there's a lovely billboard for rockets So obviously by the time this is installed you're going to the moon The people mover in Disneyland in Los Angeles looks like that God that looks beautiful. Look how beautiful that is Yeah, the beautiful Sun you're the Sun was protected the roof You had lovely open air and you got to look around all of Tomorrowland and just enjoy a lovely relaxing tour See oh Look how beautiful that is you get to watch all the people down underneath and go. Oh look at those poor people They're not on a people mover. I am and in fact That would be where Star Tours was and in 89 you would get me and my brother up there Shouting at people telling them that Star Tours was a terrible ride And they shouldn't go on it and then they would leave and then we could get into the line faster It didn't work, but it was worth a shot They've also they still have the people mover at Tomorrowland in Disney World It's slightly different you can see that it's got no roofs because the entire Course is roofed instead which makes sense because it rains like every five seconds of Florida But you can see look lovely seats a lovely tour you got your feet in your relaxed and it's beautiful There is also There are people movers all over the world. Some of them are Not as attractive This is the subway in the Dallas International Airport This is the one that was also designed by Disney Imagineers But obviously over the years they tried to modernize it and it just looks terrible And it's in Dallas So what made it the best? Continually moving no traffic even when it had to slow down still going linear induction run by electricity no fumes no massive pollution all over the place that beautiful 1960s mid-century design so great and It had a really awesome soundtrack which made it absolutely beautiful So you got to sit back and relax and enjoy it and it breaks my heart that they got rid of it at Disneyland and If you don't believe me, that's a link to a YouTube video That is the entire one it also went through the world of Tron so you could pretend that you were in Tron so that was also amazing and And Yeah, suck eggs you look Waltz did this in the 60s How dare you how dare you think you can revolutionize a people mover and How much time do I have left? Yeah, you know what? Y'all are getting two minutes of people mover music Tomorrowland enjoying this Thinking Okay, he's not the best but this is the best right ever Okay, thank you Thank you. I could listen to that music all evening. Um, we've got Thomas on next with a very fascinating title Why insects are cool and how you can grow them in your kitchen? on purpose On purpose Can you hear me all right? Okay, great. Thanks. So hi, so I'm Thomas my background is in economics But more importantly, I'm a hobbyist Olympic weight lifter So I've always been trying to look for a safe stainable protein source. This is what drew me to edible insects I Start becoming obsessed with them. I don't know how to cook them. I don't know how to farm them Now an unpaid advocate of the edible insect industry and I also wrote my bachelor thesis on it Finally, I also gifted them to my girlfriend's parents the first I met them and while they weren't really convinced So a little bit about insects so apart from the crucial role they play in our ecosystem They're also an incredible food source. They're cold-blooded creatures. So they don't waste any energy keeping warm This means that you need very little feed for them to produce edible food You don't need much water because they are efficiently extracted from moisture efficiently start moisture from fruits And they don't need much land. You can just stack in the boxes and then stack them up So environmentally they're great, but also great nutritionally They've got double the protein content of chicken and triple the its calories So they seem a pretty good solution for our climate crisis for which our food system is partly responsible for so Across centuries many cultures have been eating insects. You've got cicadas eaten by American Indians and Aristotle in Asian Greece You've got Western Europeans and Chinese eating silkworms But you've also also got the three monotheist religions all specifically mentioning locusts and grasshoppers in their text They're all halal kosher and acceptable These days most insects are eaten in more trouble regions where they're larger and more abundant But in Western countries, they're still kind of met with disgust The main reason why is because they were always associated with pests Which was obviously not a great sign for harvest But they can always also be used for other uses for example for in traditional Chinese medicine They can be you can extract oil for biofuel. They can be used for pharmaceuticals for coloring And right now there's a huge growing industry for insects as feed especially agriculture So I'm going to talk to you about insects as food. There's three main Common or popular Insect types for you today. So there's the black soldier fly Crickets and meal rooms. So I decided to start my own farm with my girlfriend with meal rooms So usually couples decide to get a dog before getting a child. Well, I decided to go with the insect route Okay, so just very simply how the cycle works is that you first get beetles Delay eggs these eggs become meal rooms and then they can become pupae and they transform it in beetles So the initial setup is pretty simple. You buy beetles online. You put them in a top or a box You want them you want it to be not transparent because they like shade You know put oats in them and a little bit of a toilet roll because I said they won't shade And then you're gonna add a little bit of vegetable or fruit scraps every so often so they have enough moisture Then after a few weeks, you can safely expect they've made a few eggs So you're gonna put these beetles in a new box. So you have one box of eggs and one box of beetles The box of eggs you're gonna let them essentially grow into mealworms when they become mealworms You have two choice one you let them become beetles So your colony grows which is great or you decide to eat them So that's time for harvest essentially. So how are you gonna harvest them? You're gonna put them in a box and there's putting them in freezer So they're in a state of semi-haber nation and that's gonna enable you just to bullet them Without them really feeling anything Which is ideally a more humane way of killing them I think that's one important issue with eating insect is that for a small amount of protein You are killing a lot of living beings. So that's one thing to take into account So me personally I haven't actually been able to kill my own mealworms because I've grown so attached to them So I think just take that into account. So right now I just have mealworms as pets more than as food Yeah, so my favorite personal favorite recipe is you pan-fry them you put some spices some barbecue sauce And you can top them on your cheesy nachos Just in this picture. These are crickets. We can do the same thing with mealworms. They're crunchy and they're great Yeah, so I hope you I've piqued your interest I've brought actually a few dried crickets for you to try so I'll be at the exit in case you want to try them Thank you. I don't know what to say after that Anybody looking forward to lunch? Before we go on to the next talk, I just have a quick question You're not volunteering yourself right now. Hold raise your hand if you can press four buttons Oh, you're not suck it in yet Keep your hand up if you liked a full cooked breakfast that you don't have to cook or pay for You can see where I'm going with this. Can't you? We need a vision mixer which basically you press a button and it changes over from slides to the holding slides Etc. Press buttons for an hour Get a free breakfast in the morning. If you're interested come see me straight after and we're going to go on to Chris's talk Which is about transporting open static data around the world So when I'm not making Poor wardrobe choices in a cold field. I'm a tech lead for city mapper. We do What? Why a quiet Well, that's all I got Yeah, hi When I like said when I'm not making poor wardrobe choices in a cold field. I'm a tech lead for city mapper one of the things we do is Deal with a lot of open data from around the world And it's it's my area specifically is static open data, which I'll explain to you in a second So what is it so in the world of transport so weirdly? There's been a lot of railway talk this this weekend so far Now it's more about buses. I guess but also railways We have kind of two types of data one is static and one is dynamic dynamic is the kind of data We talk about like when's the bus going to arrive Is a disrupted that kind of thing static data is more like what's the timetable for the next two weeks the the buses or the trains or whatever Where all the stops like what was their latlongs and what they called? What are the roots like you've got I don't know a tube line or a bus line or a bus route whatever what they called Where do they go who operates them? What time do they get to the stops and what kind of shape do they go to get there? And how much they cost The last one's quite tricky So there's quite a lot of places around the world that publishes days are openly The way they do this is kind of a bit hit and miss In terms of like standards So yeah, here's a few of them timetables inherently are complicated It might sound relatively simple like having a list of things that you know vehicles that go to different stops at different times But like does it go there on Tuesdays does it go there on bank holiday weekends? Does it go there? Throughout the entire day is it a fixed frequency or it are they specific trips that happen and do they change and you have Waiting times in different parts does it split all this kind of stuff makes this quite tricky So there's a few standards that exist for this kind of thing GTFS is probably the most widely used one it Google kind of invented it And it's pretty much the de facto standard in most places But some of the trailblazers like like the UK for example and New York to some extent Have had to invent their own standards trans exchange UK buses use a lot of transit change There's netx in Europe TFL has its own API having your own API seems to be a thing that big operators like to do. That's really annoying They'd like to do it anyway MOTC is quite good one as Taiwan Open Data API It's like really well documented super awesome Trouble is the data that goes into it is noise. Right, but that's not that's not their fault Sometimes they'll just give you like a bunch of random CSVs and they don't tell you what anything means which is really helpful So, you know, that's a problem and sometimes they don't even give you anything like a structured data They'll just give you a PDF timetable like there's literally what they would print to put in like the leaflet Holders in buses and they and that's open data apparently So you have to figure out what to do with that. Oh in Tokyo you can talk to me at Tokyo later, but that's a lot of fun So with this open data just because the standard is is fixed doesn't mean that the data is actually right One of the problems that comes up really frequently in these data feeds and that's actually picked up by a bunch of validators So GTFS validators is too fast vehicles So what happens in this particular instance is you either have stops are in the wrong place So they're too far away usually or the time that a bus calls at those two stops is Not correct either. They've done something silly like you know only added one second And then it goes over like a hundred meters and it's going a hundred meters a second quite fast for a bus Or they just like move they've Put all of the bus stops in the North Sea totally thing that happened So yeah, you see all of these buses kind of going through London then teleport into the North Sea and then teleport back again And it's obviously that's wrong Not many people want to go to the North Sea. They're so not very helpful either So yeah, there are validators that pick this kind of thing that Interestingly the validators use Rules about the mode so it knows that buses go, you know an average speed of I think it's like 50 kilometers per hour something But trains are supposed to go a hundred kilometers around We suspect that this is because it was developed by Americans who have a really bad train network And actually trains do go faster than that everywhere else in the world. So, you know, I made a poor request They didn't really like it very much Thought I was boasting anyway Let's talk a little bit about route type So route type is a field in the GTFS spec and This is the list of all of the routes that exist in the transport data So, you know the bus routes the train routes so on One of the fields is route type and this is supposed to describe what kind of a vehicle or what kind of a services run It's a relatively short list. So the one on the side is is kind of the basic ones You might think like who's got funicular or an aerial lift. It's like actually a surprising number of places have funiculars I think there's probably about 13 that I know of in Europe And cable cars there's one in London. It turns out. Well, it really doesn't use GTFS, but never mind So, yeah being able to describe things in a bit more granularity is quite helpful In particular certain kinds of regional rail services being described differently to local rail services is quite handy but When people tried to extend this Google kind of just went. Oh, yeah We'll just give you some more route types and you can just use it But they were to actually make it part of the standard for some reason So people started using them wasn't part of the standard So now everyone has to use the Google standard, which is not the standard Because everyone else is using it. So it's kind of de facto And then at some point a bunch of people said maybe we should make this official. That would be a good idea and then typically We over-engineered it We ended up adopting or trying to adopt a whole list of these vehicle types from TPag, which is a broadcast radio standard weirdly Which is designed for sending traffic informations to Navigation systems like Tom Thompson that sort of thing. I'm not sure it's actually used anywhere, but that was the intention of it So, yeah, unfortunately, this does include rather a lot of other things Which you probably would never have in a gtfs feed like post-boat surface I mean, I know they exist, but like does anyone need that in the gtfs feed? I don't know or airship service Which I mean be nice, but I don't think anyone's gonna be launching an airship service in the near future We'll see though, I guess Fairs, they're good. They're really complicated because In some places the fair system might be quite straightforward So a zoning based system relatively easy to represent Problem is that's not the same everywhere So if you want one system that is able to deal with calculating fares basically anywhere in the world You have to build a really general system and Can't remember who it said who said this but some any internal engineering project always tends toward an implementation of a Lua parser. It's kind of that's kind of where you're going with this So gtfs does support this, but it doesn't do it very well in my opinion Also Heathrow and TfL rail are a pain in the bum because they do weird things Also disruptions so traffic data You might not think hasn't got very much to do with real-time Data and disruptions but actually you do need to know it because when you look at a disruption feed a whole different Topic you need to be able to line up like what it's saying that's being disrupted with something that's in the timetable So you can when your route planning you can actually assign the disruption to the route This could be quite complicated Specifically because disruptions are often not structured. So there'll be just like some Plain text That kind of says the central line is disrupted Bank which is fine as long as you know what the central line is and the fact that it's a route what Oxford Circus is and what bank is It's quite tricky So right. This is what this is how city map it deals with all of this nonsense We have this thing. It's called cargo train. It's like one of our oldest co-basers And it does all of the transformations for all these weird data formats It also fixes things like buses that go too fast and stuff like that and just produces like a standard format which Is similar to one of those standards I mentioned earlier, but not PDF timetables because that would be silly And then we have a thing that checks The consistency of the data as well So counting the number of chips is a good way of approximating whether things have changed massively There's a whole load of other stuff and also we can validate it ourselves to see if we've introduced any errors So yeah, that's basically How that works in a very condensed period of time I'm also an amateur maker and I bought 3d printer and that became a bit of a problem for me because everything needed to be printed 3d printed and Not everything can be 3d printed a lot of things you find 3d printing is not strong enough for so I instead of Scaling back what I wanted to 3d print I decided to go the other way and find out how to Excuse me and tried to find out how to make my 3d prints stronger so the avenue that I've taken is Basically composite materials, so we are 3d printing shells for what I want to make and fill in them with epoxy resin or epoxy and some of the filler material and And this is kind of what you would need to do that. This is what you'd need to do that. I'm okay so the method is to design what you'd want to make and You need to consider how you're going to slice it when you have designed what you're going to make and So a few things like perimeters you will need at least two perimeters You cannot do base mode with this because it'll be too leaky And three perimeters are better as long as it's not a really really small part Infill if you can avoid using infill that is way way better if you need to use infill then use gyrode fill because that Connects the whole inside space of the part if you use something like grid or rectilinear you will have individual Pockets within your part which won't fill with the epoxy resin and you absolutely need four or more top layers To get a good seal if you're doing top layers And so 3d print it and so that's my Up there. That's my CAD. This is my 3d part. This is not the same 3d part obviously and You will have invisible holes that you can't see so you'll need to Fill those holes with some kind of sealant and I've used lacquer spray just like car spray paint lacquer and Once you've printed your part if you don't leave it open like this you Will need to drill some holes in your part or print in your holes and But drilling them is easier one to let the epoxy in or inject the epoxy in and one to let the air out and You can then fill your part and then wait for it to set Depending on what epoxy you use it can take a long time to set or it can be very very quick And there's a definite trade-off in what you're trying to do and so this is The part I showed you earlier with the CAD design and this is it ready to slice or being sliced and You can see I have not included a top layer To make it really easy just to pour it in I don't need to inject. I don't need to drill it. It's really simple and And you would think you can just turn off the top layers and that'd be fine But because I've got holes within that they need top layers. So if you Turn off the top layers globally for your print you won't get top layers above your holes Which is very leaky it will leak everywhere and So I've used a height modifier just to select the top few Millimetres and just said don't print the top layer over those And so this is me Sealing them pouring them and there's some other parts there which I'm injecting them So if you use a 3 mil drill bit you get perfect size hole for a normal low-lock syringe And so the reasons that I want to do that and I do this is because you can potentially Depending on what fillers and composites you use you can make your foodie prints almost as strong as adding a minimum yet, it's still workable you can still Machine it if you need to if you need to make some changes if you've got a hole in the wrong place for example Or your hole turns out too small and It's not very expensive and you can make it even cheaper if you're willing to deal with certain things which really Absolutely stink You can color it if you want and I'll show you a little bit of that later and Epoxy it is a little bit stronger and a little bit less brittle in PLA And but the main advantage is it won't fail along your layer lines. And so it's a contiguous thing inside your print and Some of the disadvantages are the shell of An object transmits most of the force so if you're putting a lot of force onto an object You need it to have a strong shell and your shell is only going to be as strong as the PLA and Small features won't get any epoxy in and that's a major pitfall which I've fallen into multiple times and PLA's never really by a biodegradable, but your print definitely won't be biodegradable if you fill it full of epoxy and things take an age to cure and You need to be a bit careful about the heat So if you get a quick curing epoxy it gives off a lot of heat and it can melt your Your shell before it actually is cured Yep, and so this is my hacky racer and this I went all out on this technique of 3d printing the shells and fill it with epoxy and you can see the results So that is one of that's the wheel that should be there is over there and it has a broken pitman arm That one has an attached pitman arm, but you can see from the angle that is not right and the collars or The steering wheel to turn on work really well and this is a lie. It is not a success. This is the reason I'm not racing it today Because the wheel fell off the steering wheel So it's back in the car And these are absolute successes and and you can see I'm putting some faith into these prints They hold up their heavy bikes. I will definitely cry if I fell on my car These are quite chunky parts. These are things from thingy first. Sorry. I haven't attributed but and they are Printed just with no top well no top layer or bottom lead and on which way up they were and filled with Glass fiber and epoxy and they will never break. I have hit them with hammers just to make sure they will not break And this is a pretty thing and so this is exactly the same technique This is just top layers and this is my house sign, but I made because the one that came with our house was disgusting so this is just for perimeters, I think it's three perimeters on this one and I've I've included the street name as well as just the same layer same height as the shell and it's filled with and Normal clear epoxy resin Deep cure so it took about three days to cure and I used about 4% and black and To make it a little bit gray a little bit of white acrylic paint It is actually a little bit transparent you can't you can't see it on here, but the little holders that clip onto the screws and are within the epoxy and They're just visible within there. It's almost like smoked glass But if you use maybe up to 10% of the acrylic you can you can get there for a link And that's it so go for make strong things. Oh pretty wings Hello Thank you Alex yet another fascinating talk, I think you'll agree They've all been really brilliant talks so she can give all the speakers another round of applause