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DIY Mech/Exoskeleton suit.

Mechs are not viable, nor cheap, so I will try to design and build one alone anyway.

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Mechs are cool and I wasted a not trivial amount of time researching about related topics that I think are equally as cool and interesting.

I hope I can build one or more mechs, but first I need to actually project one.

I will try to list in this project here all the ideas I had/have because I'm noticing that I'm repeating the same cycle of ideas, and by putting these ideas on paper, I will finally just forget this mech thing and move on to better ways of using my time and effort, or just be completely consumed by it.

I'm not an engineer (thus the enthusiasm), neither a programmer, or any other actually useful professional expertise.

Everything I use and/or make is open-source.

Also², the Artist of the pic/painting of this project is "Ukitakumuki Kai Lim", you can find their profile on Devianart, the specific pic is called: "Project Boots: PANAM Armour" (and it is cool as heck).
And no, the artist is in not working in this project

I wrote a recent project log talking about the problems that need to be solved in order to make a viable mech/exoskeleton suit:

Project Log 74: Tech Tree for Mechs¹.

Project Log 75: Tech Tree for Mechs².

This is me from the future (16/01/2024) and I severely misscalculated something:

Project Log 76: Mechs are not viable.


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This is a guide, not a instruction's book.

Well, the idea of this project is to be more of a guide-book rather than a rule-book, I will make my own stuff, but it doesn't mean you can't learn other things that could be useful for your specific needs.

Plus, I'm not even an engineer, a professional would have finished this project a long time ago.

The project logs are long and counting up, my apologies for that, but if you want to really just start where the project truly starts, go to Project Log 54 forward.

Previous project logs are more or less about exploring every option that I could find and learning all the necessary stuff for the project rather than an actual manual.

That's why I think it could be relevant for you to read everything first if you aren't familiar with engineering in general, or if you just want to understand why I abandoned certain ideas and kept working with other.
During the project, I changed my mind a myriad of different times about how to build this thing, and in hindsight, I think it was for the best.

So I think it is worth making the choice of studying every option before actually committing to build it. I saved so much money that I would otherwise have expended for dead ends that I didn't knew it were dead ends.

Right now I'm writing Project Log 68, so I'm more or less on the "final steps" before actually building the thing itself.

Again, this is not a "connect part 2B with part 3A in this way", this is more of a "I connected part 1, 2 and 3 this way because I think it would be stronger and easier to build, if there is a better way, I don't know, but I heard that you could connect these parts in a X configuration, which I never tested before" kind of DIY guide.


Index:

Bearing.zip

DIY Slew Bearing for Exoskeleton as stated on Project Log 69: https://hackaday.io/project/188391-diy-mechexoskeleton-suit/log/222406-project-log-69-diy-endoskeleton-and-exoskeleton It is a blender archive compressed in a zip archive, which I should have done sooner.

x-zip-compressed - 39.45 MB - 09/20/2023 at 21:07

Download

Electric motor.zip

3D models of the DIY electric motors mentioned on Project Log 58: https://hackaday.io/project/188391-diy-mechexoskeleton-suit/log/220958-project-log-58-diy-electric-motor

x-zip-compressed - 23.72 MB - 09/11/2023 at 17:20

Download

DIY Hydraulic Pump - 1, 2 & 3.zip

Mold for stator, gearbox, "motorbox" and hydraulic pump as stated in Project Log 68: https://hackaday.io/project/188391-diy-mechexoskeleton-suit/log/222346-project-log-68-diy-hydraulic-pump (Hackaday limits singular archives to be uploaded to 50mb, so I compressed to this one here)

x-zip-compressed - 36.26 MB - 09/11/2023 at 17:17

Download

  • Project log 79: Testing things out.

    FulanoDetail02/03/2024 at 19:07 6 comments

    03/02/2024, 15:55, Saturday.

    You know what? I will just post this and let anyone willing to help, give me a hand, because gawd, do I need it...


    Well, I feel like I'm being ahead of myself again and creating this project log too soon....

    In either way, I spent another 300 reais (60 dollars) to buy other materials. But I will only be able to buy the rest of the materials next month (thus my concern to make this too soon).

    Now I will have the adjustable power source, silicone rubber, dielectric silicone grease, silicon carbide, sodium silicate and sucrose.


    An odd selection of materials, but let me explain them:

    • The silicone rubber will be used to mix with graphite powder (which I already have) for the dielectric elastomer electrodes.
    • The silicone grease will be used to make the dielectric layer on the dielectric elastomer.
      Yes, I did say that I would use Polyvinyl Alcohol and Polyvinyl Acetate to change the positive side and the negative side. But it would be cheaper to do the way I'm doing, after all, I will just test it out.
    • The sodium silicate, silicon carbide and sucrose will be used to make the porous heater.
      I will mix the three with water and once it is solidified, I will heat it over until the sucrose turns into dust, leaving a porous structure behind.
      I will use it to test if I can turn 1 liter of water into steam in 1 minute without requiring 47 kilowatts.

    However, I'm still missing a few things, like the high voltage low amperage transformer for the dielectric elastomer actuator and dielectric pump and the PVA for the hydrogel heater I talked about in Project Log 77.

    I will take another month to buy these two and test it out.


    After all of that, I still need to test my hypothesis on the eccentric electric motor that I also talked about in Project Log 77.

    That one will require 3D modelling and 3D printing.

    ... Which I didn't even started yet... y-y


    Well, the adjustable power source just arrived, but I can't use because it doesn't come with a fricking plug.
    It is supposed to be fed by another power source, either from a bigger adjustable power source or one of those switched power supply.

    And I don't have one of these, I mean, I have one, but it is not for this voltage.

    Either way I will have to wait for another fricking month until I can actually test some things out.

    And yes, I can only spend 300 brazilian bucks per month.



    Highly Porous Heater:

    Since I already have all the materials to make this one, I'm still highly confused about the ratios I need for this thing.

    I should've had thought this through (history of my life), because I'm pretty sure I would need to test various ratios for the perfect heater in this case.

    And I just have a kilogram for each material.

    I really should've paid someone to do this for me (like I had any money to do so)...


    Although... I think it would be easier to make it porous if I used alcohol or the like...? Well, I will test it out on both cases, I bought more than enough anyway...

    I also tried to search for electric steam generators that uses silicon carbide as porous heaters, but I had no sucess until now. If I could find a single article talking about it, I could've spared around 100 brazilian bucks...

    By the way, Sucrose is just common sugar, I definitely didn't just waste 60 bucks on buying a chemical grade Sucrose without checking it first. Definitely not, this would be very stupid of me.

    Just now, after asking for 298398392398th time, chatgpt suggested me using salt. and then dissolve it in water... And paraffin wax...

    I mean, WHY DIDN'T I THINK OF THAT BEFORE?!

    I could just have used carbon fiber as the heater...


    In any way, here are some of the ratios I will be testing:

    • In the first try I will go with the gut, I will measure the amount...
    Read more »

  • Project Log 78: The Quest for the Universal Fuel Engine

    FulanoDetail01/26/2024 at 12:03 6 comments

    Friday, 26/01/2024, 08:43

    Well, since I bought my power source from Aliexpress, the goddang thing will take 75 days (and some times, more), so I have a plenty of time doing a whole of nothing involving this project.


    You know what? I'm getting a little bit pissed off with myself.

    I keep repeating myself over and over with "let's make a turbine, no, let's make a stirling engine, no, let's make a fuel cell, no, let's make a plastic piston engine, no-"

    For f-ck sake, I should just shut up and just do something instead of listing 12932893282389 options that I will never use.

    ... Well, it would help a whole lot if I had any money to begin with...

    (this is my hobby, I do it for fun, I'm having a lot of fun)



    Let's talk about energy sources.

    What I mean by "universal fuel engine" is that there are multifuel engines that can work with multiple types of fuel, but a lot of them have a small range of fuels.

    Of course, you probably don't really need a universal fuel engine, but since I'm broke, the most probable fuel that I will find is grass and wood.

    You can't put grass and wood in a turbine engine, neither a piston engine.


    Asking to ChatGPT and BingGPT, steam turbine engines can convert fuel into heat, and thus steam with an incredible efficiency, around 80% or even more.

    Of course, this is not a surprise if you ever saw anything about stationary energy production, like one of those giant turbine geneartors.

    The bigger the blades, the more efficient they are, not to mention that the whole facility is specially built in order to make the finest control possible on fuel, fuel burn and heat exchange.

    Of course, the compromise is size.

    Not an issue for a energy generation facility, an issue if you want something energy dense, portable and efficient.


    These madlads are building a monstertruck motorcycle, and the engine they are using (as shown in the thumbnail) has 150 horsepower, fits in a backpack and could easily power an exoskeleton.

    The issues are:

    • It can only use a single type of fuel.
    • The generators are many times heavier and bigger than the combustion engine.
    • Low efficiency, around 30% (not low for combustion piston engines).

    Of course, I did find some interesting articles about ultra high speed alternators that could possibly solve the issue of generator size and weight.

    (this is a conventional 10 kilowatt AC dynamo generator and it "just" weights half a ton)

    The articles in question are the following:

    Of course, these are really small energy outputs, but look at the size of said generators, one of them is as small as a match head.

    This means that it would be easier to use a gear box that multiplies the rpm instead of torque.

    Of course, there are very low rpm geneartors, but these are not really compact. Although, they are very easy to make... At the cost of size.




    Universal Fuel cells:

    Basically, the first thought I had was to use a universal fuel cell, which was the idea of having a fuel cell that can directly use any kind of hydrocarbon fuel.

    Of course, I'm not a company, and my Co2 footprint would be completely meaningless compared to the smallest airplane, lol.

    In any manner, these supposedly "universal" fuel cells are called "direct carbon fuel cells", and apparently, the most promising ones (accordingly to the wikipedia article) are the solid oxide fuel cells and the molten carbonate fuel cells.

    Both are equally complicated on their own, and both are extremely expensive on their own also. On top of that, information is limited I can barely find anything online.


    Another possibility is the use of hydrides.

    There are multiple types of...

    Read more »

  • Project Log 77: The quest for the Miliwatt Actuator.

    FulanoDetail01/21/2024 at 12:45 1 comment

    21/01/2024, 08:22, Sunday.

    I'm quite stoopid, I already said I gave up on the project, but I can't, for the life of me, just give up.

    And besides, like I said on previous logs: looking for artificial muscles/soft actuators is my hobby now.


    What I need to look for?

    In any manner, using electric motors and combustion engines is a no-go for robotics, since a human speed exosuit/mech/robot would need megawatts of power to lift tons of weight, the only way I can make these viable is to reduce the consumption for at least 100 times.

    And for that, I need to find a good actuator option that has a power-consumption below 1 watt in order to make this thing viable, more precisely, around Miliwatts of power. Which is 0.001 watts.

    Electric motors are complex machines, but are very reliable and precise, I would love to "simply" make an electric motor that uses 0.3 watts (or less) per kilogram of force at 40m/s of speed... But it is not that simple.

    One way I could think of was to reduce the air gap between the stator and the rotor to micrometer or nanometer distances. After all, the smaller the distance between electromagnets, the stronger the electromagnetic field.

    The issue is: the stronger the electromagnetic field, the stronger the eddy current, the reluctance and a myriad of different things.

    Every type of electric motor is an ecosystem on its own, and in order to figure it out, I would need to understand the fundamentals of electric motors.


    With that in mind, I found myself looking at a concept called "zero air gap permanent magnetic machines" with this paper: https://digital.wpi.edu/pdfviewer/9p2909417

    One of the suggestions is using ferrofluids to "close" the gap, but as far as I could see it, it actually had some substantial effects, like almost doubling the torque of the electric motor.

    But still nothing close to miliwatts...

    It makes me question if the micro/nanometer gap would even make any difference at all...

    Ah, by the way, the article talks about a company specialized in super tight tolerances and super dense brushless motors called "Thin Gap", which uses a slotless winding that I couldn't quite grasp how it is done.

    This one is said to have 100 kilowatts of power.

    The paper I linked above kinda explained how these are done, but I don't think I quite grasped it yet.

    In any manner, I can't find anything on the subject as much as I like, so I don't think I will have any luck trying to DIY my way into this type of exotic BLDC motor (and unfortunately, I would love to)...


    I also searched for other articles:

    If I didn't read it incorrectly, you can achieve up to 4 times more torque with the same amount of energy, which would reduce the power consumption from 3 megawatts to "just" 750 kilowatts, which is like, 1000 horsepower to lift 1 ton of weight.

    Very interesting results, but nothing close to miliwatts...

    They achieved that (if I'm not mistaken) by making the electric motor's rotor enccentric, so it physically touches the stator's teeth, like a radial piston engine, except with electromagnets instead.

    So, if they literally physically touch and can only multiply the torque by 4 to 5 times, then this is probably a dead end.

    The only reason the rotor strength doesn't increase even more is due to the fact that it is eccentric, only a small part of the rotor is touching. Only 2 teeths out of 17 teeths are in direct contact with the stator, so I could imagine a maximum increase of 8.5 in torque if full contact was possible. And it would probably be possible by stacking the eccentric just like radial engines did:

    Assuming a...

    Read more »

  • Project Log 76: Mechs are not viable.

    FulanoDetail01/17/2024 at 00:23 2 comments

    16/01/2024, Tuesday, 20:47

    I'm not dying, by the way, just the project, lol.

    Basically, I was recalculating everything over and over again because since day one I had a flea behind my ear.

    First I thought "making a mech is actually somewhat easy, they just didn't take this seriously enough because they have more useful things, like a forklift", but being serious, I didn't really think this was a good enough reason for that, but couldn't pin-point why.

    Then while searching for artificial muscles and their linear speeds, I found out that the human muscle can achieve linear speeds of over 40 centimeters per second.

    And when I put in the numbers, I understood my mistake.


    Converting the 40cm/s of linear speed with the 1/10 mechanical disadvantage of the human body in a forearm with 30cm of length, the rpm of the arm would reach 250 RPM, or 4 meters per second of linear speed (I heard that a punch can reach 45 km per hour of linear speed).

    Now, if we input these numbers in an mech arm with 60 cm of length (since the entire mech is twice the size of an average human), and we maintain the linear speed of 4 meters per second, which would give 130 rpm, we would need 6000 newton-meters to lift 1000kg.
    By the way, it doesn't matter if the load is put in a difference distance, if it is going to lift 1000kg on the tip of 60cm, the lever arm length won't change the final wattage, no matter how you tweak the rpm and torque, you can't scape the laws of physics.

    And, if you input the numbers in a torque to horsepower calculator, it gives you 81,686 watts, or 109 horsepower.

    If we take the more "whatever" approach and simply say that the arm and shoulder are the same, the torso uses the same amount of energy and the legs use 3 times more, it would still give 545 horsepower, or 408,750 watts.

    This is basically half a megawatt.

    If we take a somewhat precise approach and simply multiply the other limbs force requirement by 3, the numbers go bonkers.

    109 hp to the forearm + (109x3) to the shoulder, ((109x3)x3) to the torso, (((109x3)x3)x3) to the legs, which would give: 

    4360 horsepower or 3,270,000 watts of power.

    You would need 3 megawatts of power to a simple mech that moves at same speed as a human being.

    It is not "super speed", just "super strength", you would still run miserable 10 km/h with the mech (average human running speed), maybe 20km/h due to the double size of the limbs (a mech even slower than this could be viable, but what would be the point?)

    And a exosuit with 100kg of lifting capacity would use 145 horsepower/109,000 watts, not much lower than the mech (a exosuit even slower than this could be viable, but what would be the point?²).

    Plus, I'm calculating only a 100% efficient machine, which is not possible. With inneficiencies, the energy consumption would increase even more.

    In any manner:

    My apologies, I thought mechs were viable due to a math mistake I've made.

    I will left the project on so anyone enthusiastic enough (like me) will just skip all the homework.

    Anyway, it was cool to read about all types of subjects, including artificial muscles and the sorts, and I don't really think I will stop looking at this subject.

    This mech/exosuit thingie was more like a hobby were I was having a lot of fun searching about this stuff.

    But even so, I feel kinda stupid in a manner. Like I wasted my time due to a silly mistake.

    Live and Learn, I suppose.

    (by the way, the mechs in Armored Core's lightest Mechs weight around 35 tons)

    But, as a consolation prize, maybe walkers will be viable, since they don't need to carry the extra weight the arms and torso would need to carry. xD

    Maybe some day I actually try to make a walker-forklift hybrid, but who knows...



    The only thing that makes me question whenever or not this math is sound is the human body...

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  • Project Log 75: Tech Tree for Mechs².

    FulanoDetail12/07/2023 at 10:15 6 comments

    It happens that I wrote so much on the first Project Log 74: Tech Tree for Mechs¹. that the hackaday Website started deleting older text. :|

    I contacted the Hackaday email asking if it was possible to check older edits so I can copy the part that was deleted (I received an automatic email response saying they would take like a week to answer).

    ... And no, I don't write my project logs in a other documents. Yes, I'm that stupid.

    ... And that is why I completely lost whatever it was deleted. Forever. :|


    -----------------------------------------------------------------------------------------------------------------------------------------------


    I literally cannot write a single new phrase on the previous project log, but basically, I think it would be worth it making the electromagnetic artificial muscle I suggested making with the nanometer 3D printer with actually the airbrush 3D printer.

    I know that it would take ages 3D printing and calibrating properly, but it would still be possible. I just don't know if it would be viable or practical, still, you would face the same problems relating to 3D printing electronics with resin and metal powder.


    Well, I'm still not actually giving up on the mech idea, but I'm simply have a lot of difficulty find solutions (cheap and simple solutions) for the actuator problem.

    Like I said in the previous project log: I settled on at least trying to find a way of making a solenoid pump or something that can be used as a pump and doesn't need electric motors, combustion engines nor piezoelectrics.

    Electric motors are expensive and need really big batteries, combustion engines are low efficiency, expensive, heavy and need solenoid valves, piezoelectrics can't be homemade, aren't efficient and neither can pump massive volumes.

    I mentioned the possibility of using Nitinol Shape Memory Alloys, but those have efficiencies below 20% and cost 500 dollars per kilogram.


    By the way, while asking my trillion of random questions over and over again, ChatGPT said that the conversion of electricity into heat (using a heater like Nichrome or other types) is almost 99% efficient, and that the conversion of heat into steam using this method is almost 99% also (I searched online and it seems to check out). 
    So, there is also the option of using steam to pump the fluid or something else. You could use steam instead of pneumatics or hydraulics, you could use it to make a steam engines ( that are around 40% efficient) and so on (turbine engines sit around 65% to 90%). I also believe that steam powered artificial muscles would be as efficient as pneumatic ones (30% of efficiency or less) because they are essentially the same thing, but using different fluids.

    Source: https://www.science.org/doi/10.1126/scirobotics.aaz4239
    It is a unthetered artificial muscle in which induction heaters are used to heat iron oxide nano-particles in order to turn water into steam, making the muscle actuate. It is less efficient than what I'm suggesting.

    But I don't know which is the best method, and to be honest, I don't feel comfortable carrying an electric steam boiler on something that can simply fall on the ground and break what is basically a bomb.


    The few positives that I can think of would be the speed of actuation, compared to hydraulics and electric motors, it is hard something as fast as a pneumatic actuator consuming the same amount of energy.

    Not to mention that you wouldn't need the power of a turbine engine to compress thousands of liters of air.

    ... But it is also not that simple.

    I would need to calculate how many liters of water you would need for a given pressure and flow of steam, which, as far as I could calculate in the past, it ins't that hard, but it isn't that easy either. It would entirely depend on the full system.

    1 liter of water produces 1600 liters of...

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  • Project Log 74: Tech Tree for Mechs¹.

    FulanoDetail10/15/2023 at 12:49 4 comments

    15/10/2023, 09:49, Sunday.

    Well, good morning.

    I was planning on making this project log on 26 of november, which would be the 1 year anniversary of this waste of time of a project.

    But I will make this now because I need to take this out of my mind.


    But yes, I'm giving up on the project (for now, I think), and I will list all the problems that need to be overcome in order to make this project viable.

    Which could be easily overcome by an actual engineer, but since I'm not one....


    ------------------------------------------------------------------------------------------------------------------------------------------------


    So, Mech, or Mechanoids (humanoid + mechanical) are not practical, nor viable, without some problems being solved.

    One could definitely make a mech, but it would be unholy expensive and unnecessarily complex for something that can be easily replaced by a goddang forklift.

    Thus I would like to list all the problems one would need to solve in order to actually make something viable.

    (tech tree from mechwarrior)



    First: Power Source.

    One would need to find a power source that is light, somewhat efficient, compact and cheap enough to be used in a humanoid mech.


    Out of the batch, batteries won't cut it.

    These have low energy density, 10 to 20 times less energy density than fuel. Which is normally measure in either by weigth or by volume (which doesn't make sense to me, since density is volume divided by mass) in the watt-hour per kg.

    Lithium-ion batteries have 100 to 200 wh/kg of energy, meaning that if you want 15,000 watts in 1 hour, you would need at least a 150kg battery (with various smaller batteries stacked or not), and since you would need any kind of machine work for several hours, you would need to add 150kg for every hour of operation.

    Which is not really practical.

    In the other hand, gasoline has 12,000 watt-hours per kg, but due to the innefficiencies of combustion engines, you would actually have 5400 wh/kg.


    Edit⁴:

    So, now I'm completely confused.

    Well, long story-short, I was looking at how much energy a laser weapon would consume, and it said it would consume 10,000 joules per shot, which would consume 20,000 watts in total, around 26 horsepower.

    However, an AA battery has a total 10,000 joules of energy, but can only output 5 watts.

    Meaning that a single AA battery would be able to energize a fricking laser weapon in a total of 30 min.


    The thing is: I understand batteries as a "life bar", if the battery has 5 watts, and you connect it to a 5 watt consuming source, it would consume 5 watts and deplete. Simple as that.

    ... But... There is a relation between Watt (the maximum output) and Joules (the total energy in the battery), which relates to watt-hour (it is the total energy consumed over a 1 hour at a constant rate of one watt).

    ... This means... That I can extract... The equivalent of 26 horsepower out of a single AA battery?

    ... Then... Why there is all that fuss about "batteries not being energetically dense enough for cars"?

    I... I don't understand...



    Conventional combustion engine generators are efficient, but they aren't cheap and definitely not light. Commercial diesel engine generators with some as "little" as 2000 watts to 4000 watts weights 100kg.

    More potent generators are way heavier and way more expensive, the price of cars even.


    I even thought on using a micro turbine engine with a high speed alternator, which would be way lighter, but these aren't cheap, easy to make, nor efficient.

    This one is a 8 kilowatt microturbine generator, I literally cannot find anything like that online, but taking into consideration that turbine engines uses titanium alloys and/or inconel alloys, it definitely ain't cheap.


    Edit¹:

    Just now I remembered about free-piston turbines, basically, it is a piston engine that uses its...

    Read more »

  • Project Log 73: DIY Endoskeleton and Exoskeleton.²

    FulanoDetail09/13/2023 at 15:35 1 comment

    Wednesday, 13/09/2023, 12:13

    I'm feeling like whatever the hell I wrote in these "serious" project logs are complete nonsense, not only because I'm talking things with almost no basis in fact, but also because it looks like writings of a mad man.

    I was simply trying to read previous project logs and I mix texts were I wrote it in the past and parts that I wrote in the present, so I may be referring to something like I'm talking about "the previous subject matter" but there are multiple paragraphs referring to something completly different.

    ... Which makes me wanna make more project logs that are more organized...

    ... But I'm holding myself to not do such bullshitery simply because I didn't finish the goddang 3D models yet.


    -----------------------------------------------------------------------------------------------------------------------------------------------


    Well... Hi, good day, good afternoon and good night.

    I'm still in an awful mood, but I would guess that it would be useful to simply do something (anything) rather than do nothing.

    And well...  I'm just going to post here everything I need to watch so I stop procrastinating...


    ... It is kinda funny how I plainly said that this project is dead on Project Details, but I keep going with the project.


    Being honest, if I had the money, I would've pay someone actually skilled to make this project a reality instead of cracking my head against the wall...


    To be honest², even though I'm watching video per video, I'm not understanding half of the stuff that I'm looking at.

    ... I really need help with this project...


    -----------------------------------------------------------------------------------------------------------------------------------------------


    Also, one thing that I forgot to talk about in all these project logs: remelting of 3D printed parts.

    Basically, you could 3D print parts with 100% infill, put them in a medium such as plaster/gypsum and then put the thing inside an oven with more or less the melting point of the plastic being used and take it out.

    Basically, 3D prints have a problem of layer adhesion, meaning that all 3D printed parts are basically a pile of sheets of paper-thin plastic layers held together by the adhesion of its surface.

    By remelting the parts, you are turning the entire thing in one solid piece of plastic.

    I saw other methods that use salt instead of plaster.


    In anyway, you could commission 3D printed parts on a plastic of your choosing (such as HDPE) on one of those 3D print online stores and use this method to make the parts stronger.

    Plus, you could drill the parts and infuse them with fillers such as steel wire and such.

    Or just embed the wire on the 3D print during printing. lol


    I just saw this video from the same channel, it is another interesting option.

    Although carbon fiber is expensive, glass fiber isn't that much.


    You could use either method to make the 3d printed parts stronger:

    • Drill holes and inserting the steel wires and remelting.
    • Drill holes and inserting carbon fiber/glass fiber and remelting.
    • Injecting epoxy with glass/carbon fiber in the 3D print.

    -----------------------------------------------------------------------------------------------------------------------------------------------


    Well, I was looking into buying slew bearings and make copies of them, and while I was doing that I stumbled upon this video.

    I don't know what material it uses for the flat bearing plates that it has, but I thought it was an interesting concept.

    Plus, I did like the idea of inserting limiters on the ring in order to, well, limit its rotation.


    This means that the bearings that I've made aren't suitable as the way they are now, I need to remake them with a better concept in mind.

    ... Read more »

  • Project Log 72: DIY Hydraulic Pump.²

    FulanoDetail09/03/2023 at 16:31 4 comments

    03/09/2023, 13:20, Sunday.

    Well, I'm writing this² after finishing this project log because I feel like I failed this project log.

    Even though I reached a few conclusions on how much energy I would require depending on the type of pump I used, I didn't reach any satisfactory conclusion.

    Neither did I make any useful 3D model.

    I will try again later and maybe this little message will be deleted, but still.


    ----------------------------------------------------------------------------------------------------------------------------------------------


    So, I'm writting this here because I had some ideas for making a cheap DIY pump, my stupid brain simply insists that I'm simply not trying hard enough when there is simply no easy way of doing these kinds of things.


    ----------------------------------------------------------------------------------------------------------------------------------------------


    Well, where do I start?

    I was checking some other solenoid valves that aren't 5kg of force, and decided to at least give a try with the 25 newton solenoids.

    This one weights 100 grams, but I would bet it is more likely because of the steel part rather than the copper coil.
    In either way, you could use aluminium wire instead of copper, but it is a little bit cheaper per kg than copper.

    Anyway, this one uses 4.8 watts of power, but in some sites it says it uses 30 watts.

    So I thought on making a free piston/plunger with 7mm to 8mm of diameter (needing a force of 19 Newtons to 25 Newtons respectively) moving 50 times a second, it will be able to achieve 1.5 liters per minute in each side of the pump, so 3 liters per minute in total.
    This would be able to more or less actuate two filament artificial muscles, however, if you braid those like intended, you would use longer muscles that in turn would need more fluid flow.

    Now, for the working principle you have two options:

    1. Using a soft iron core with two coils that will alternatively pull the free piston torwards in alternating turns.
    2. Using a Neodymium magnet as the free piston with a single coil that will change the electromagnetic poles, making the magnet move up or down.

    Both have advantages and disadvantages, but let's remember that this thing will be moving 50 times a second, I'm confident the iron core can handle it, but I don't know about the neodymium magnet.

    In both cases you will need a way of knowing where the free piston is, using some kind of sensor.

    First I thought on using a hall sensor or a mechanical switch, but the hall sensor has to take into consideration the electromagnetic field and the mechanical switch has to take into consideration the pressure inside the chamber, so it doesn't activate with the pressure.

    I'm pretty sure there is a easier way of doing that, but I couldn't think of anything.


    With a 1kg of copper and 100gram coil per solenoid pump consuming around 30 watts of power, you would be able to power 20 muscles, or in the worst case, 10 muscles.

    Since 1kg of copper wire is 100 reais (20 dollars), you would use 1500 to 3000 reais (300 to 600 dollars) in total. Not so dissimilar than the 10 dollar brushless motor.

    But the downside of the brushless motor is that it needs a reduction gear and a very bulky hydraulic gear pump.


    Now, about the hydraulic gear pump and/or the axial piston pump.

    One thing I was very clear on talking about was the precision between the parts, which I don't really think it would be easier (or possible) to do in a DIY way.

    The idea would be to simply do two things:

    1. Using a glass plate with abrasive material on it.
    2. And/or using a DIY lathe.

    The glass is the flatest surface that one could have at home, so by using it like a "sand paper", you could achieve incredibly flat surfaces.

    In this video the guy does something similar, at the 6 minute mark.

    This will be useful both for the axial piston pump...

    Read more »

  • Project Log 71: DIY Linear Actuator.⁴

    FulanoDetail08/24/2023 at 12:07 3 comments

    Thursday, 08:31, 24/08/2023

    Well, morning.

    By the time that I actually start making the exo/endo-skeleton, it will be buried under 3983932382 project logs.

    ... But I think this is relevant, because I need to talk about Dielectric Elastomers and I already wrote so much crap on the previous project logs about linear actuators that hackaday simply starts deleting new text on them.


    Just to recaptulate:

    The hydraulic artificial muscle system, although being lighter and allowing a higher efficiency, since it is lighter than metal hydraulic cylinders, its oil still weights a lot.
    More or less 180kg to 225kg.

    So I thought "hey, since I'm already facing such inneficiencies with such system, then why not try something else?"

    Then I calculated pneumatics, but those are inneficient as heck and quite dangerous to work with.

    Then I thought on Dielectric Elastomer Actuators, those wouldn't need an electric to mechanical to hydraulic conversion and make a somewhat efficient system, even if these aren't that efficient in the first place.


    In any way, I was absolutely sure about the efficiency of dielectric elastomers to be really low, but after looking into some review papers of dieletric elastomers, I'm not so sure.

    You see, for some reason, when I look at dielectric elastomers review papers (such as the one bellow), they always say that the efficiency of DEA's are around 80% to 90%.

    https://onlinelibrary.wiley.com/doi/epdf/10.1002/aisy.202000282

    ... But when I "ask around" and/or search for specific articles with new DEA's, it is always something bellow 40% efficiency.

    And the problem is: when I try to look into the bibliographic sources these review articles use, instead of leading me to specific studies, they send me to older review papers with the same efficiency reference and I can't find the actual production method.

    Bro, I'm reading articles from the early 2000's and I still didn't find a single fricking method of production (or I simply didn't pay enough attention, I have ADHD after all).

    The article in question: 

    https://link.springer.com/article/10.1557/PROC-600-119

    You will need sci-hub to see it, but basically, it says it uses something related to acrylic.


    In either way, there are 2 options here:

    • Either I'm simply not reading the full information (since I'm literally fast scrolling though everything, that's my fault).
    • Either some articles simply take references without double-checking their sources (which is doubtful).
    • Either they are talking about dielectrict elastomer generators (that convert mechanical energy into electrical) instead of actuators.

    A 4th option would be that the movement that the dielectric elastomer makes is highly efficient, but the elasticity of the material reduces the efficiency.

    Most of the dielectric elastomers have a really low actuation, in the milimeters of actuation, so they need to make a reversebly actuated artificial muscle, just like the hydraulic ones I was thinking on making.

    And thus, the necessity of making the muscle relax when voltage is on and contract when the voltage is off means a low efficiency of energy transmission.


    Also, I thought on two ways of making dielectric elastomer artificial muscles systems.

    Basically, I either do the reversebly actuated or the membrane actuated.

    At more or less 2:11 time in the video, you can see how big it is the actuation of the membrane, if you were to pass a shaft/rope through the membrane and stacked a lof of these membranes, you could make an artificial muscle pull it up.

    Something akin to this, but with a rope instead of a rigid shaft.

    Now, the reversibly actuated you already know: you make a strand, when voltage is on, the strand relaxes, increasing length, and once the voltage is off, the strand contracts.


    Or maybe neither of these, but continuum design (aka tentacles):


    I posted it at the...

    Read more »

  • Project Log 70: DIY Hydrogen Fuel Cell.⁴

    FulanoDetail08/21/2023 at 11:51 0 comments

    Monday, 21/08/2023, 08:09.

    --------------------------------------------------------


    Edit¹:

    Well, this is me from the future, if I remember correctly, almost all of this project log is useless.

    But hey, I found this video here:


    It is about catalytic condensers.

    Basically, if you apply a current through certain materials, you will change the amount of electrons on its surface, just like in a capacitor.

    This change in electrons makes certains materials act as catalytic materials, just like platinum, palladium and others.

    Maybe one could use cheap materials for catalytic condensers for hydrogen fuel cells, the problem is: which ones and how?

    The video talks about more or less how these work and its use to produce hydrogen from ammonia, but I don't know how one could make a useful catalytic condenser in a DIY setup.

    I'm trying to find more on the subject, but with no success.´


    I can only find articles about veeeery specific catalytic condensers, some for acid groups, others for processors (that use platinum for some reason).


    I also don't know for the life of me how much energy would these things need to act as catalysts, meaning it will inevitably affect the overall efficiency of the fuel cell.

    -----------------------------------------------------------------------------------------------------------------------------------------------


    Well, my apologies, but I think I found something interesting. Basically, you can store hydrogen gas in solid Naphthalene.

    (I feel like someone told me about this before and I stupidly ignored them, but I don't quite remember)


    As you may remember, I kinda gave up on the idea of using hydrogen as a fuel because hydrogen is pretty difficult to store, you either need carbon fiber 700 bar (70 MPa) pressure hydrogen gas tanks (which are expensive) or metal hydrides (which are triple expensive), but I think I found something interesting.

    ChatGPT is kinda annoying to work with, because you really need to make the right questions in the right order to get the information that you need.

    And it never cared to explain that there are other ways of storing hydrogen on solid compounds besides metal hydrides.


    Let's also remember that ChatGPT can be strongly incorrect about a subject.

    Although it told me a lot, every time I try to get a useful information, it keeps saying that his knowledge was cut in 2021 and tells me to update to the premium version.

    Basically telling me to screw off unless I have money.


    For example, it first told me that you could store 66kg of hydrogen gas in 1kg of naphthalene, then I asked if he was correct and then changed to 6% of hydrogen per kg of Naphthalene.

    You could also store it on activated carbon and/or titanium powder, but it would be around 1 to 2% per kg.


    "Yes, there are liquids that can dissolve and store hydrogen gas. One example is organic liquids that are highly hydrogenated and have a high solubility for hydrogen gas. These liquids are often referred to as "liquid organic hydrogen carriers" (LOHCs). LOHCs are typically organic compounds that can reversibly bind and release hydrogen gas through chemical reactions.
    Here's how the process generally works:
    1. Absorption: The LOHC molecule reacts with hydrogen gas to form a hydrogenated version of the molecule.
    2. Storage: The hydrogenated LOHC is stable and can be stored at room temperature and atmospheric pressure.
    3. Desorption: When needed, the hydrogen gas can be released from the hydrogenated LOHC by reversing the reaction, which typically requires adding energy (e.g., heat).
    The advantage of using LOHCs is that they offer a way to store and transport hydrogen gas without the need for high-pressure tanks, which are often required for storing gaseous hydrogen. This can enhance the safety and practicality of hydrogen storage and transportation.
    Another example is using certain ionic...
    Read more »

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