 I'm Sarah. I love lasers a lot besides FPGAs. In the fablab of Karlsruhe, which the fablab is oriented at the ideas of the fablab idea of the MIT, we got funding for a laser sour. The laser sour is an open source project. You can see it on the screen. It's a huge machine. It's this size. I want to talk about it. I want to talk about what you've done, what went wrong, what was bad in the original design, what we have tried to make better, where we fell in, what mistakes we made. I want to encourage other spaces to also build laser sour because it's quite a bang for the buck. I mean, five to six Ks, you get a hundred watt machine. It's not that much. My background is laser marking development, laser system development. What you can see, this is a professional or industrial laser system, which is in a production line. Some parts pass by, they get a barcode marked on and continues. This is what I've developed for the last two and a half years. It's a YAK laser. It operates at the YF length of 1064 nanometers, which is near infrared, which is perfect and amazing for metals. You can engrave, you can do a lot of things with also with plastics. This machine got me started into the laser world and gave me the passion for laser marking. I love it when I've seen it a lot of time. It's like the washing machine and kids effect. You put a kid in front of the washing machine when it runs and the kid stares like this. This is the same with the laser beam. I can't stop watching. I love it. The machine, what I'm going to talk about, the structure. I want to talk about the laser cell itself. Then I want to get into it in the detail, how the beam runs, the pros and cons of the original design. This is very important. It is not what we've done, but this is what's out of the box. Then what we've done in mechanically or in electrically ways, and then there's a very painful issue that's calibration. One last which hasn't made it into the talk yet is what you shouldn't do. By the way, this is the tube. This is the actual laser tube from our laser cell. We had a small mishap, so I could bring it here. It's toast. The laser cell runs with this CO2 laser tube. It has 100 watt optical laser power, which is quite a lot. It goes through 12 to 15 millimeters wood, like with a hot knife into butter. This is quite impressive. Also acrylic and other plastics. The CO2 laser is with the wavelength of 1,064 nanometers. They're very, very good at organic materials like wood or paper, leather, skin. I made some experiments with a pig skin. It goes right through. It smells like if you don't want to smell. Acrylic, plastics, but what's totally, totally, this is a strong warning to everyone who plays with lasers. Don't use PVC or any other chlorine-containing materials. This will decompose. This will reorganize the molecules of the chlorine, and you will have a fume of HDCL, hydrochloric acid. This will make your machine from the inside rusty immediately. Don't do. You see the website, lasersower.com. The plans are online. You can download them. There's a forum where you can have access to what other people did. I haven't been into this community too much, but it seems to be quite interesting. The working area is quite large. You have 1 meter 20 times 60 centimeters. This is huge. You can put a large piece of wood or plastic in and do whatever you want. This is amazing. And also the speed. We've tested it with 10,000 millimeters minutes. Cutting speed, this goes and the wood is cut into pieces. Quite impressive. About the CO2 itself, I mean, this tube with 100 watt optical power is, it's about a grand with the power supply. The lasers I use for my work, it's a 20 watt system. They are in the range of 6 kilo euros. This is a totally different story. You can have a lot of energy for quite a little money. For example, the laser cutter, the laser cutting systems for metal working, for these sheets of metal, they use the CO2. Normally CO2 doesn't work very well with metals, but you can throw a lot of energy into it and then you can cut metal. So you need one, two, three kilowatt of light, but it's cheap. You can afford it. It has quite a high efficiency compared to other gas lasers. You don't need 10 kilowatts to get 500 milliwatts optical power out of it. So conclusion, happiness from a tube. So we go to the path of light. On top, you see this tube. Then to the right, I hope it should be the right right. You see the first mirror which stands still. This is the first mirror in the mounting where the laser itself goes like this and this stands still. Then the M2 is the second mirror. This is on the y-axis which moves and the mirror M3 is on the x-axis and this deflects the beam down side through the lens. Painful to calibrate. I will come to it later, but that you have a rough idea how the setup is. It is basically this classic plotto principle. You have the x, y thingy going around. This is done by stepper motors. No, you don't need any big machines, any big stepper motors. You can have the small NEMA, I don't know, 17 whatsoever, to operate the system. So pros. Not so beefy on the prize. You can do it in your space, which is an awesome idea. You need to have three, four, five, six people who know what they do. You need to have some electrically experience. You need to have some mechanically experience. Off you go. By the parts, build yourself. We had a lot of fun. We had the mechanical group. We had the electrical group. I was in the electrical group because of my experience with laser safety. The user interface is quite easy. This is in the stock. There's a board that is plugged in a Beaglebound black. There runs a web server, which you access via browser, and you put in SVG files. What's nice is you can have many colours of SVG files, and to every colour you assign a specific energy, like speed, marking speed, and a percentage of energy. So you can engrave in the first run, then in the second run, you cut out the drill holes, and in the last run, you cut out the outlines. It works. It has its flaws. We try to mod. I don't know if we have it on GitHub yet. We try to implement the, to see how long does the job last? How long is the tube on? So we can see how much every user has to pay. Right now, thinking about one euro per minute, because filter systems are quite expensive, and the tube itself doesn't last until Kingdom comes. Yeah. If you can download the software, I don't have any screenshots, but you can tinker with it. It runs on, it's a Python thingy running. I'm not into software, I'm a hardware person. So coming to the contrary sides, first of all, it has no z-axis. Now, electrical z-axis or z-axis. You have this honeycomb aluminum flat bed where you put your material on, and then you have a tube which is too far. Oh, thanks. On the left-hand side, right-hand side picture, you see the third mirror, you see the head, where it is basically the tube with a holder, and you can adjust the tube. And this way, you can adjust the focus, which means you can have sort of a z-axis. But this is only about 50 millimeters. I've seen other machines where you can adjust the height of the table electrically. Some have done, you can tilt it, which is very nice, but the design of the laser is how it doesn't have it. Something to go into and do a redesign. Then they use in the original design patch cables, Ethernet patch cables you get from your supplier. It has nothing to do with Ethernet, with the protocol or with the speed. The thing is, you have a very cheap cable, you can get in quite some distances, and you have readily made a connector onto. Again, nothing about network, it is just DC running through and very low, very static signals. The only point was the connectors on the suggestion of the board, RJ45, so everything is made cheap. The con of this solution is the cables are very stiff, and if you use it in a drag chain, you go backward and forward, and backward and forward. Try it with a network cable, do it 100 times, bend it, and you will have a cable break. Some mechanical details were not so nice. The one we realized is that it can flex, it has no diagonal stiffings, things to stiffen the whole frame. If you lift up one side, it goes like this, and it is not adjusted anymore. We had some problems in the lab because it is an old slaughterhouse, and we got the cooling room, and the floor is not flat, it goes to the middle of the room where there is a drain. We pushed forward the laser, did our adjustments for a couple of days, and yes, it works. We pushed it back and nothing worked. If some of you are mechanically in experience and know what you have to do, then don't use this original design. In the suggestion, they left open how to handle the air. When you cut with a laser, when you do anything material processing with a laser, you will have fumes, you will have small particles, they are just there, and you need to get rid of them. The easiest way is you have one hole on the other side, and you have a fan on the other side, and it just sucks the air through. We did it basically this way, and we got a lot of vortexes going around, and it is like in a snowstorm where you have, in one end of a house, suddenly, in Germany, it is called Schneewe. A lot of snow, and the other side is there is no snow, and just by the wind. You have a lot of dust in the machine, which is in one corner, and the other area, it is nothing, and the mirrors are dirty, and so there is a lot of room for errors. We haven't figured it out yet perfectly, it became better. We have another fan with, I don't know how many cubic meters per hour, I think one and a half thousand cubic meters per hour of airflow. This makes it a bit easier, and makes it a bit better, and we have a filter system, but realized when the filter becomes clogged, the airflow isn't that much anymore, and we start again having these vortexes. So there is a lot of room to think about. The original design doesn't care about the EN6850, which is the standard, the European standard for laser systems. It starts with the emergency stop switch, it continues with an interlock circuitry, and it is not safe. You can't use it out of the box, you can use it alone at home in your basement, or in the garage if no one else comes, then you can do whatever you want, but not as soon as there are more people involved who might also not know about lasers. So that's a bit weak. I mean, they come from America, this design is American, and I know these standards are quite strict. They are similar to the 6850 norm standard. They should have followed it. So this is one of the mechanical things. When you see, this is the holder for the big boom, which goes in Y-axis, and there's this other piece which goes in X-axis, and there are three long screws into the extruded aluminum profile, and they're quite long, and after some time of operation we realized it got a bit loose, and these screws, they warped a bit. So suddenly we could turn this boom, and of immediately you have fun with the adjustment of the beam. So room for improvement. And then it comes to electrical. Yes. We had the problem that when you switch on the laser source and you fire, the integrated Beaglebone black crashes, and we didn't know why. And it was on Sundays, it was okay, and some days it was really bad, so you make a single shot and everything is crashed. It took us a while. I grabbed my oscilloscope from work and connected it to the PulseWidth modulator to output from the Beaglebone via an AVR, which does the G-code interpretation into the stepping, step-dir commands, and into the PWM, pulls with modulation to the laser source. And what you see on the bottom line, the pink one, is the signal that I saw on the PCB going out of the laser source. At first you see it is the 5 volt logic. It looks nice, and then we have a lot of bursts going up and down, up and down, minus 5, minus 7 volts, and plus 10, plus 12 volts. I forgot the other traces, and we realized that the power supply is sort of firing back. There are a lot of EMI problems. So the power supply fired back, and the pink line is what comes out of the AVR. So it goes back on the AVR and makes the AVR crash. Yeah. I don't want to talk about E-waste out of the box. No, I'm not going to talk about E-waste out of the box, but it comes close to it. By the way, this electronics, this stock electronics is done. Is it? It is open source. Yeah, that's fantastic. Let's do open source and have no clue about what we do. It's done in fritzing. If anyone who knows about fritzing, you can have, it is very good, if you have a breadboard, if you have three resistors and two LEDs and connected, maybe, to some embedded board, go with it. That's fine. As long as you have more, and you do a larger schematic and are crazy enough to make a PCB out of it, no way. Don't do it. You can't click like in other EDA programs, like EGLE or CAD or whatever, you click on a trace and it's highlighted and it says which name it has. On fritzing, you click on it and you just see it is just highlighted between two junctions. There is no consistency between the schematic and the PCB itself. I had to connect this board. We had difficulties with the time. We had a deadline. The laser saw was a university project or Institute for Technique Folgenabschätzel. It was a scientific project and we had a strict deadline. We couldn't develop a known board. We had to use this and we had to live with it. I had to connect it and I got so cranky so many times. I was close to throw it through a closed window and smash everything into pieces. Painful. Enough of the rant. What you see on the left-hand side is, I did try to bring it into EGLE to make pictures. What you see is basically how it looks like. You have the AVR, you have two wires, two traces to the RJ45 connector, nothing else, no protection, no nothing. For the inputs, for the end switches, so X and Y have end switches and for the big door, you have also switches. For the end switches, at least you have a pull-down resistor. This is something I wouldn't consider to publish. Because the solder stop was black, you couldn't see any traces. With a loop and a lot of guessing, I put in an inductor against EMI distortions. I had the capacitor and the synodiode to at least cut these tremendous enormous oven undershoots and it works much better. Still, this is a work round and it was a lot of work to get the SMD components onto this board and a lot of scratching of cutting of copper traces and so no fun, really no fun. But we did something. What we did in modifications is this is a beam catcher. This is for the beam going from the first to the second mirror. In case the first mirror is not adjusted, you don't know where it's going to shoot the beam. We have this ceramic tire so that if you don't hit the second mirror spot on, the beam doesn't go somewhere else. So if the hood is closed, nothing will happen. It is acrylic and acrylic is for the unfocused beam is quite safe. You see what happens. You smell it. It works. But we use the ceramic tiles on many places. Nothing happens if you shoot. We also use the ceramic tiles on the floor. We first had captain. Captain is a fantastic material. If you have a PCB and you go through the solder wave and you want to you have some holes you don't want to be filled with solder so you have this captain type and you stick it onto and nothing happens. Very thermal resistant but not good for a laser and someone had the idea it wasn't me. Let's stick captain on it and when you shoot with a laser it makes funny things, funny films and toxic things. So we use the ceramics and what you can see on the floor is where the laser was going on cutting through wood. You have compressed air through this tube. There is a lens and there is the nozzle and you put in some compressed air so that no fume goes onto the lens to make it dark and to blow away all the fumes and to cool the spot where the laser beam goes into the material that nothing ignites. Heat plus wood plus oxygen fire. So it goes through the wood and leaves some traces on the tiles. Quite impressive. So what else did we do? It's a bit tricky to see that we did a beam labyrinth. When you close the hood according to the original design and you open it a little bit there's a possibility that the beam goes through and goes into a room where you stand. So it's just an aluminum angle we screwed on on one of the extruded aluminum. Just sort of make it safer. Then we changed the tube holder. It's so funny. The original design was you had an aluminum piece of metal and another one and it goes like clock and there's this delicate glass tube inside. So no we did something else and the benefit is we can adjust it in height which is very important for the process of calibrating the laser. Then we tried to improve our airflow system. This was a test on the left hand side. We tried to split the intake and air into what goes above the cutting area and below to get away the fumes. We are still not finished yet. On the other picture you see the dust from cutting wood. This is what I told about the vortexes and leaving dust traces everywhere. So then we did when you operate a laser and do some material you cut through something you will have or engrave it you will have a lot of dust and this dust can be very toxic and this dust can be smelly can stink and you don't want to let it go let it how you don't want to have it in your lab or in your space and you don't want to let it out unfiltered. So we designed a filter system which has five stages going from going finer and finer until the the two black things are this way are carbon active carbon filters which take out which filter the last smelly bits and pieces. This works quite well. You have to maintain it you have to look for the filters when one filter gets clogged you see it that you again have these vortexes so the the reduces the pressure and the airflow and we changed the out the these area for for suction that we cut out on one side the air stream goes in and on the other side in the floor it goes down and sucked out to the bottom. What else yeah I mentioned few traces on the mirrors are very bad because you lose energy the mirrors will heat up it's not good we tried to 3d print covers for for the mirrors. This is one of our latest iteration with this long glass tube if someone has a better idea so please I'm open to any suggestions it makes it a bit better we have less traces on on the mirrors on the left hand side you see the original design it is just the mirror holder and the tube and you have a lot of air and space around for any dust and any fumes and any smoke it gets a bit better we are still not at the end from where we want to go so electrically we made some electrical changes we haven't changed the board the the electronics board yet it is still in discussion we have a lot of ideas floating around a lot of different theories how how this laser has to be made but we we did some changes compared to original design sorry first of all we use an e-stop relay which which prevents an automatic which that we don't have an automatic restart so you do something you hit the e-stop switch the beam will go out immediately and the motors from the x and y axis stop working immediately it is not emergency off it is an emergency stop and so the the the PCB the the electronics still is alive you get data back you can do something but it is the idea behind is that the dangerous thing is shut down not the machine itself just the dangerous parts are shut down um our relay is from dollars we got it from ebay for affordable money and it's something to do we put we made an interlock circuitry interlock circuitry means that if not all the conditions are fulfilled you can't have a laser beam so if you interrupt this interlock circuitry like you open the the hood um or the the the door um then the beam will go off immediately so it is you can do it laser chop and why the job is running you open the the hood and the beam is stopped immediately and the the the x and y continue working doing their thing you can put away something what you've forgotten you can close it the beam will continue um um so also when you switch off the the chiller i will come to cooling later that's the reason why the tube is here um and also the the air system the the compressed air which goes into the tube is within the interlock circuitry and as well as the suction system so you simply don't want to have that fumes in the in the system we did it once i don't know how it came we did we had it once someone came up with a big piece of acrylic or whatever polycarbonate material highlights can can we just do a quick cut i don't want to to use a table saw circular saw whatever yeah sure put it in it was still in construction closer at all and we haven't had the the extraction in the interlock circuitry we forgot to switch on the fan and immediately the the chamber was filled with this yellowish fumes and it took us half an hour in wintertime to get all the smoke out of the lap you don't want to have this and we changed from these patch cables which are easy to break uh to something nicer so we used we actually used oil flex from lab carbon which is a very nice cable which is very suitable for drag chains you can go around back and forth a million times it doesn't break very very thin very fine flexible thin wires excellent cable no i'm not related to lab carbon this is our electrical this is operating on the on the right hand side you see the main switch for power mains the chiller switch air and for the laser source and you see the e-stop switch and the greenish the green button is the release the the the e-stop relay so processes you switch on the machine then you open the padlock which we use according to en 6850 you need to have a for class four laser system you need to have a switch a key switch or numpad or something like that only um people are allowed to use the laser actually can use the laser so remove the laser um the the keypad and padlock release the the e-stop switch and push on the green button and you're good to go and when you actually want to do something you switch on chiller which is quite quite the chiller is quiet um you switch it on right after you switch on the machine and then air is quite noisy you just switch on air when you want actually want to laser something um so there is sort of an e-stop functionality on the webs on the on the web front and on the website but it is nothing has nothing to do with a with an e-stop with a serious e-stop so in panic when something goes wrong you don't want to click somewhere and find a button where was a button where was e-stop up top right corner okay let's click oh shit missed um you want to have a serious one and it stops the the danger immediately so then we ran into these troubles with the emi problems from the laser source and we had the idea that that our beagle bone was defective that something destroyed something on the board it is just three volts tolerant the ios and if there comes something more it is very itchy on this this issue uh then it dies so on the on the larger piece you see the avr and the rest of the electronics um which does the g-coat interpretation and this is connected via our receive and transmit it's a standard serial connection on ttr level and then it goes to the beagle bone and then it goes via ethernet to the outside world and we we took out the beagle bone and we had to have another embedded on board and we simply replaced it uh this works so calibration um calibration is pain in the neck seriously straightforward text days makes a lot of gray hairs um it's necessary you need to calibrate the system you need to calibrate the system where the laser is going to stand finally as i said before we have the the floor in the lab is not horizontally not leveled but it goes it goes slightly downwards um you need to have it in that place if you don't have a perfectly leveled floor you need to level everything go with this water level check out diagonal horizontal vertical axis all these needs to be leveled um and then you need to have the the beam coming from the tube this is the fun part the fun it goes to the first mirror it has to hit the first mirror from the height in the middle and then you go to the second mirror and has to hit it on all positions in the same height and then you go to the third um so it is a lot of opening closing screws um going back again again again through the cycle until you have it all the beam goes and run on pain um playing not pain um and um we did something to to help to to calibrate calibrate this laser this is basically um how the mirror holder looks like it is a piece of aluminum and so the beam comes from here and you have this piece of aluminum and this this way and you have the actual mirror goes a bit inside it is a bit um like a mirror frame um and we use to we stick it and label um I come from the labeling industry um we we stick an label a thermal sensitive label onto this frame and the actual mirror is not the same um height it it is three millimeters deeper um so you need to do some calculations and you see on the left hand side um this is actually in vertical and you see that the beam doesn't hit it in the middle but it hit it has to hit it a bit below um what you did is um yeah this these are shots from onto these thermal sensitive paper and here you see on the on the left hand side what it just meant the the beam holder and the mirror and it is behind the the front of the of the mirror holder and um so the two images the two shots on the thermal sensitive papers are quite okay uh so we stick this this paper onto the mirror holder and with a fingernail or with a back of a knife we just mark it so this is this sorter circle this funny polinom polygon um so that we then um have a tool it is on a printed on foil um and on the right hand side you see this it looks like a fingerprint but if you center it on the on the spot where the where the beam hit the paper you can see how far off you are from how far you have to adjust the mirror so this is you make a shot you you put it on you mark two millimeters too far okay then you you open the screw lift the the mirror holder for two millimeters you do again the same shot takes days um i want to to to put these files on my website and also as a file on on the talk yeah it's difficult to describe um if someone wants to know how it works uh fablab is in Karlsruhe we are very open to to visitors please come to visits um um and we can show you so things you shouldn't not do uh you should not fry your tube it's expensive this one is fried um very simple reason totally stupid reason um the the chiller is a system uh it has a water pump it has two water pumps so it's redundant um it has a cooling system with with a compressor and everything it is a fantastic machine but if the plug this here slips out then you then you're done then you're finished it happened and five minutes after first time laser on this day at my just piff light was off and water run over through the whole machine and i don't know how much water is inside but the pump was fortunately not functioning so it didn't continue pumping water through the electronics of the laser system um yeah expensive expensive experience um this is something you should avoid always check your cooling system and always check the water security beside all other things um great if you like you can contact me uh sarah at laserlady.org soon we'll use you will see this talk on this website soon you will see the talk from the gpn 15 on this website if you can contact me if you have any questions um feel free um i want to thank all the guys here at the camp for this awesome time i want to thank the fablab karlsruhe and i also want to thank the itas institute for technique following upsets in karlsruhe which did the funding and which helped us a lot and we had a lot of fun together as you can see on the picture below um we have some time left i'm out of slides now if you want to know something feel free now we can do for the q and a we have a lot of time because this is the last talk in this tent for the camp 2015 and at first thank you for your patience and thanks for listening and which doc is doing the q and a okay thank you sarah um we have some people here i'll start over on my right um at hackerspace hack 42 we have a laos laser yeah and we have had quite some issues with the accuracy of the code itself that it doesn't calculate the laser position correctly we have any problems like that in laser sarah is it just that just works fine all the time uh it works fine because um it works with absolute positions when you switch on the machine you have to run the homing cycle which means it goes in x and y axis at the on the top left corner there is zero zero um so it goes to the first end switch and goes to the next end switch um and then it knows here's zero and then you can do whatever you like and it knows where the head is is it that was it your question um my question was that uh with laos you could get uh for example you do an entire run and you go back to the zero position but it's not exactly at zero position it makes a small error but during the cycle ouch no this this doesn't happen with her with her lasers our electronics it is sometimes it really happens that um you can do a lot of things with parameters right or wrong so let's say you go through three millimeters uh would you choose a thousand millimeter speed and let's say not to to treat the tube but you go with 50 percent and then you're here run and afterwards you see if it goes through or not um and you have the feeling no it didn't work then you can do again the same the same run the same job again and again as long as you don't touch anything inside like you move the wood piece of wood nothing happens it goes exactly the same contours exactly the same traces um but i wouldn't recommend this hardware very much um yeah we've used the laos hardware and the hardware itself is basically from what i hear from you uh in quality roughly the same as the laser saw okay also no safety inherent safety in it at all what we're going to do is as i mentioned before um we want to do our own laser bars um with my experience in laser safety there will be an fpga for all the safety circuitry and uh some more benefits one what we actually want to do with the laser is doing big data we want to monitor the the temperatures of the mirror of the tube of water in water out water flow how many times or how long the laser tube is running and this and that and that and we want to integrate it into our lab net and and store the data on the server so we can see slow changes for example in the temperature of a mirror so we can see well it's time to clean or so we we get some more experience more data for having experience um yeah the last i heard the name last but maybe i have seen it but i can't remember but it's if you say it's the same no i don't say um if it's the same type of boards there are some others uh smoothie boards i heard has should be okay in supports also lasers but they all don't have these laser safety circuitry was it yeah did i answer your question you answered it fine thank you you're welcome okay and we have another question over there uh hello uh i'm leaving standard faplab brussels thank you for the interesting talk another faplab yes yes uh we don't have a laser saw yet i worked with one in antwerp they um you just answered my first question uh about the controller yeah um my second question would be if i want to build it on a smaller budget as a student project where would you compromise um at the tube do a sexy what instead of a hundred yes yes um a hundred what is is fun sure um i mean nothing replaces power so good like more power everyone knows it same like memory um but you can do a lot with a 60 or 50 sometimes 40 watt tube um this is about the 1000 1200 euros um if you can have a cheaper uh what i just learned is that if you can have let's say 100 watt in this size or if you can have 100 watt in smaller size larger i don't know but in a different size and it's cheaper but the beam quality is less is not so nice i mean you have seen the images on on the papers uh the small shots it was just small shots with very low energy on the paper to get this to get a bit um to see where the laser beam goes um it looks like a donut so the energy distribution in the beam is like this and um the beam doesn't go out collimated oh it's my glasses um so the beam widens up and the way how much how far it winds up this is one quality parameter and the cheaper the tube the more you have this um i would go with a high quality but less energy tube um you want to have a high quality or you want to have the beam as good as possible um you kind of have a lot of energy but if the beam is is crap um then you have problem adjusting the system and mics are fun and uh you can compensate less energy with slower motion off the head you don't need to run 8 000 millimeters per minute what you couldn't can do with this tube but then you go on 2000 millimeters or you go with 100 or whatever i would i would save the money on the tube get a good quality but you don't need that much energy um and i think it doesn't there is no linearity in how big the machine is i think if you have an aluminum uh profile if you have it one meter or 80 centimeters there's a big difference so go big build the machine in the full size but um with less energy it doesn't hurt yes thank you you're welcome okay then we have another question over here yeah please hello my name is avid and uh i wanted to thank you for your nice talk it's very interesting um we in our hacker space are planning to build uh laser sara 2 and so i wanted to ask we are not really sure how much it will cost us so i wanted to ask you um how much uh are the costs only for the materials if you doesn't broke anything and the second question is um how many people were you to build that up and how many uh man hours or woman hours sorry uh you put in hold got it um uh the the pricing um as far as you know we've been between five and a half and six grams five and a half and six thousand euros and this was a thousand one hundred so just take this out of the calculation you will be good with um four four and a half case but you can do if you think twice about the design there are some there is some room to save some money to make things more intelligent more smarter you you will find better solutions it is quite cool if you have some mechanical engineering guys over it it is not the end of what's possible in the design and yeah i'll find another board um sorry i forgot the two last other questions the second question was how many hours you put in into the project until everything was running we had two building weekends meaning we met on friday afternoon we had the mechanical group and we had the electrical group the mechanical group had about two weeks weekend's building uh which means beginning friday afternoon working till late night three two three four o'clock next day saturday meeting in the morning about ten working late having supplies of marty of pizza what's necessary and working late and on sunday not so much but working till 10 o'clock in the evening so we had about two weekends this style and one as far as i remember one uh weekend for the electrical system so we've been i don't know how many guys have maybe the mechanical setup i think it was three four to five guys um i don't know if they've been there all the time together or if they did shifts um from the electrical side we've been three to four guys and we tried to to to distribute the work one was working on this area and the other one this area and we tried to get the cables around because you stand in cables you have wires rounded around around and open ends and you yeah um i would say if you're focused if you have everything ready a theme for good weekends or let's say one week of vacations from morning to evening you can do it okay same yeah please okay then we have one more question over there yeah you got uh plenty of modifications to the laser zauer design so in which website can you find them out in non um i don't know where we got the laser holders the laser tube holders in plastic parts um i don't know where we bought all the parts uh we bought the electronics at the north tax lamps north lamps um it is the webshop round the license how where we got some special water cut aluminum parts um they have these if you get a sheet of metal eight millimeters thick aluminum with some special parts and there you get also the the the mirror holders and you get also the tube and and also the electronics one thing i forgot about the the mirror holders one thing we want to modify we haven't done yet is it is nice you can pan until the mirrors but you can't move them up and backward and forward you can't move them in the three axes this is something very very important for for calibrating the laser because otherwise if you want to change something you have to open an m m4 m5 screw because it's this aluminum profile and you open the screw you shift it two millimeters in one way and you close the screw you can all imagine what happens you have to start from the beginning um yeah we haven't found these uh mirror holders yet but um we got a lot of from from this north north labs webshop the electronics we're going to build we will publish open source of course um but i don't think we will sell them maybe we sell the PCBs i don't know it's it's not not um decided yet and ebay is a fantastic source this this emergency stop relay is from ebay uh the the three switches for or the four switches are from ebay um the the emergency stop switch was from ebay you have to look okay on which website you plan to publish source um first of all is fablab minus cardsword dot de this is where i live um this is my space and then it will i guess it will be published on github something thank you you're welcome i think that concludes the questions there's no more okay it's really over then yeah thank you very much yeah thank you all guys build more leises