[HN Gopher] I designed a cube that balances itself on a corner
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I designed a cube that balances itself on a corner
Author : dutchkiwifruit
Score : 1061 points
Date : 2024-02-11 16:36 UTC (6 hours ago)
(HTM) web link (willempennings.nl)
(TXT) w3m dump (willempennings.nl)
| sema4hacker wrote:
| I'm actually more enamored with the cool look of the thing rather
| than the fact that it can balance.
| ayhanfuat wrote:
| Same. Immediately checked if it is for sale (apparently it
| costs $2500 if you do it yourself).
| pavel_lishin wrote:
| I wonder what the cheapest possible build for something like
| this is, if you loosen enough constraints - let's say, if we
| allow it to be externally powered, and agree that size
| doesn't matter.
|
| Would it be cheaper (and/or safer) to build a larger one,
| allowing for larger-but-slower flywheels? Could you make one
| out of a couple of scrap bicycles?
| JKCalhoun wrote:
| Would be fun to try and low-cost it. I can already imagine
| replacing the aluminum face parts with laser-cut acrylic. It
| also sounds like the motors are another expensive part that
| likely can be low-costed.
|
| The stainless steel flywheels though..... No ideas.
| pavel_lishin wrote:
| I wonder if it would be possible to balance this thing by
| sloshing fluid around, or with linear actuators moving
| weights around.
|
| Or maybe a pair of motors, moving two circles with weights
| on their rims around, to shift the center of gravity around
| until it's stable enough to park them on opposite sides?
| duskwuff wrote:
| > I wonder if it would be possible to balance this thing
| by sloshing fluid around, or with linear actuators moving
| weights around.
|
| No. The reaction wheels are generating torque to change
| the orientation of the cube, not just shifting its center
| of gravity.
| s0rce wrote:
| Not really sloshing but you can pump fluid in tubes to
| mimic a reaction wheel
| https://ntrs.nasa.gov/citations/19910016066 Can also
| probably provide some thermal advantages as well. Oh
| neat, you can use a direct current electromagnetic pump
| to implement this with liquid metal as the fluid
| 10.1016/j.actaastro.2013.11.030
| pavel_lishin wrote:
| Right, that's how this cube - and how satellites - work.
| But would other approaches be feasible for a desk toy or
| an art object?
| johndough wrote:
| What are cheap alternatives for motors/drivers? I imagine
| there are cheap brushless RC motors which might work, but
| not sure about the electronic speed controller.
| YZF wrote:
| I suspect motors and drivers used for drones/quadcopters
| will work in this application as well. Those should be
| pretty cheap. You can do all the controls in software,
| you just need the right (I guess sensorless) driver.
| YZF wrote:
| Just brainstorming here but I don't think they need to be
| particularly precise or strong. You can likely use many
| materials as long as you can get enough weight (lead
| weights?) on the circumference. E.g. 3d print the flywheel
| structure (can be made thicker for rigidity if that's an
| issue) and glue some lead weights on. Looks like you can
| have slightly larger wheels too.
| dutchkiwifruit wrote:
| I spent quite some time (almost) perfectly aligning my
| reaction wheels. Vibrations at multiple thousands of RPMs
| are no joke. Then again, such speeds are typically
| unnecessary once the cube has settled into its
| equilibrium position. ReM-RC on YouTube has built a
| similar cube which uses 3D-printed wheels with steel
| bolts in the circumference [1].
|
| My wheels are oversized when you just consider the
| balancing application, but I want to add jump-up
| functionality later, and the wheels need significant
| inertia (and also need to run at significant speeds) to
| accomplish that.
|
| [1] https://youtu.be/AJQZFHJzwt4
| YZF wrote:
| Cool. The 3d printed wheels presumably would have some
| dampening properties vs. the steel ones. You can also
| attempt to balance them at speed (moving/adding/removing
| the weights) to try and minimize vibrations like you do
| with motorcycle or car wheels (I guess there's multiple
| modes though).
|
| Fun project!
| newaccount74 wrote:
| If you can make the flywheels flat, you could cut them with
| a waterjet, which would be cheaper and faster than milling.
| And I assume that you can use normal steel instead of
| stainless steel.
| amelius wrote:
| Next I want to see a pencil that balances itself on its tip.
| ASalazarMX wrote:
| If the pencil can be very short, just put this cube on top of
| it.
| amelius wrote:
| It would lose its form factor of a pencil.
| pavel_lishin wrote:
| What about a coin that always lands on its edge?
| dutchkiwifruit wrote:
| No worries: https://youtu.be/woCdjbsjbPg
| rq1 wrote:
| Probability courses would be funny with that thing.
|
| Roll the dice.
| dutchkiwifruit wrote:
| The house always wins!
| otto2 wrote:
| Cool functionality aside, it looks beautiful.
| dave333 wrote:
| So cool! Wondering if this technology can be used to control
| spacecraft attitude or does it require a fixed support? How heavy
| do the flywheels need to be in relation to the total weight?
| auxym wrote:
| As mentioned in the article, reaction wheels are the standard
| method used to control satellite attitude.
| glfharris wrote:
| Totally does work, lots of spacecraft use reaction wheels to
| control attitude.
| CaptainOfCoit wrote:
| > Wondering if this technology can be used to control
| spacecraft attitude
|
| It can indeed, and is already used in the wild today!
|
| https://en.wikipedia.org/wiki/Reaction_wheel#Examples_of_spa...
| jessriedel wrote:
| That list has three examples, but to be clear for others:
| Nearly every satellite has reaction wheels. There are
| literally tens of thousands of reaction wheels in orbit.
| dave333 wrote:
| I guess I have watched Apollo 13 too many times and was
| under the mistaken impression spacecraft still used
| propellant thrusters for attitude control.
| eternauta3k wrote:
| They still do!
| progman32 wrote:
| To add, reaction control is used in conjunction with
| reaction wheels. When the wheels saturate, the rockets
| are used to desaturate them.
| dutchkiwifruit wrote:
| Thank you! The weight of each wheel is approximately 220 g,
| whereas the total weight of the cube including wheels is 1700
| g.
| gniv wrote:
| This is cool. Is this how robots normally balance themselves, or
| are there implementations that don't require spinning wheels?
| phkahler wrote:
| If you've got 2 wheels side by side like a Segway, all you need
| is the IMU and those 2 wheels.
| gniv wrote:
| True, but for something like this, would it work with a
| magnet?
| rvnx wrote:
| This is what you'd need:
|
| https://eu.mouser.com/ProductDetail/TDK-
| InvenSense/ICM-20948...
| mrjet wrote:
| Most robots are passively balanced by having multiple wheels on
| the ground. Walking robots balance actively without active
| gyros by moving their limbs.
|
| Spacecraft (which most roboticists would call robots) typically
| orient themselves using a combination of reaction wheels,
| magnetic torquers and thrusters. The reaction wheels spin
| rotate the aircraft by "taking" angular momentum into their own
| rotation. They don't require a local magnetic field or the
| expenditure of fuel, so are a nice choice.
| CaptainOfCoit wrote:
| > or are there implementations that don't require spinning
| wheels
|
| Tons of different implementations out there for balancing.
| Maybe the most common one is the one we humans use, which
| requires zero wheels :)
| noman-land wrote:
| How does ours work?
| WJW wrote:
| Legs
| ponector wrote:
| Some people can balance without legs.
| CaptainOfCoit wrote:
| Input, processing, output.
|
| Sensors, brain, muscle movement.
| gniv wrote:
| Speaking of which, any good videos on how we balance
| ourselves when standing?
|
| And beyond the muscle mechanics, do we understand what the
| brain is doing? For example, I find it fascinating that I
| cannot balance myself on one foot if I close my eyes. So
| obviously we use some visual cues to balance.
| febusravenga wrote:
| > I cannot balance myself on one foot if I close my eyes.
|
| Skill issue. I'm good at balance sports and can say that
| balancing on one foot with closed eyes is hard but doable.
| Just train it :)
| omoikane wrote:
| My first reaction when I see one of these is "where can I buy
| one?" And then I realize that it's not unlike having an open-face
| blender with those flywheels spinning at 6000 rpm. I am not sure
| I would feel comfortable with something like that near my hands.
| binarymax wrote:
| Maybe some thin plexiglass around it would be fine - not sure
| if it would compromise the mechanism though.
| dutchkiwifruit wrote:
| My envisioned solution to this - very real! - danger is to
| attach some very thin round sheets of steel to the wheels such
| that you can't stick your fingers in them.
| hirako2000 wrote:
| On sundays I usually get hyped reaching new heights with code.
| Gratified by pushing perseverance and crearivity. then I come
| across posts like this one and feel totally powerless, having
| very short patience span, and too scared to even try such things.
| ASalazarMX wrote:
| Why are you on Hacker News instead of practicing your software
| engineering skills? -50 points for Griffindor!
| pavel_lishin wrote:
| Yeah, but this is kind of orthogonal to what you and I do.
|
| I felt pretty good over the past few weeks after finally
| starting to learn React on the side, and building something
| that some of my friends are going to use. Sure, it doesn't have
| the "whoa" factor, but it also didn't cost $2500 to build (not
| including the years [decades?]) spent learning.
| rvnx wrote:
| If you feel bad about yourself because of that, think of it
| not like something personal, it's a lot connected to the
| environment you are from, and some factors cannot be
| controlled.
|
| It's actually the ultimate sign of luxury when you have time
| to study, AND resources to go to a good school, AND enough
| free time and money to spend on gadgets, AND you can afford
| to throw thousands on something useless, etc.
|
| (All that said, the creation is cool and very nice work from
| Willem specifically)
| cortesoft wrote:
| If someone else being better at something discourages you, you
| are going to have a bad time in life. Very few people are going
| to be the best at the world at anything, but that doesn't
| matter. It doesn't change what you can do.
| dr_kiszonka wrote:
| You could start by following basic tutorials and getting kits
| from places like adafruit. Many of them don't even require
| soldering. For me, starting from scratch is (too) hard because
| you need to figure out what components would work together, how
| much power you need, etc.
| KaiserPro wrote:
| The thing to do here would be to remove two dimensions first,
| it makes things _lot_ easier, and you can use off the self/hand
| made parts.
| navane wrote:
| Reminds me of the self balancing train that rode on a single,
| small rail track. Project got cancelled because the double rail
| system was already well established.
| ravenstine wrote:
| Isn't it more likely that idea got abandoned because a failure
| of the balancing system would be catastrophic?
| rvnx wrote:
| + intensive in terms of energy usage + needed a second gyro
| to feel like you are standing in a flat environment.
| IggleSniggle wrote:
| Iirc the second gyro is necessary to ensure the train
| doesn't course correct itself right off the rail in the
| case of a curve? Coupled together to make the "correct"
| side more responsive for any given direction? Dunno.
| FinnKuhn wrote:
| you would also need a gyro in each train car, so that
| doesn't help
| navane wrote:
| As a sibling of yours pointed out above, the train worked
| with CMGs, their energy usage seems not too much:
|
| "CMGs are also far more power efficient. For a few hundred
| watts and about 100 kg of mass, large CMGs have produced
| thousands of newton meters of torque. A reaction wheel of
| similar capability would require megawatts of power."
| progval wrote:
| Details for the curious:
| https://en.wikipedia.org/wiki/Gyro_monorail
| https://www.youtube.com/watch?v=kUYzuAJeg3M
| nealabq wrote:
| Note that reaction wheels do not make use of gyroscopic torque
| (which balances these monorails). They are different control
| mechanisms. Altho both use spinning wheels.
|
| More info:
| https://en.wikipedia.org/wiki/Control_moment_gyroscope
| dtgriscom wrote:
| The gyroscopic action of the cube's momentum wheels must make
| the control algorithms quite entertaining.
| cmehdy wrote:
| > Like any experienced controls engineer, I spent a few days
| flipping the signs of various signals before I got them right.
|
| As somebody with a M.Sc. in controls & signal processing (who
| ended up doing way more boring things), I always figured that I
| was doing that because I wasn't experienced enough. Turns out I
| also had the sign wrong on that one all along!
| bchasknga wrote:
| You are not alone. I've come to terms with the reality that
| every controller I've designed and implemented will always need
| a good amount of unit test coverage to ensure proper behavior
| (like signs and directions)...
| noiv wrote:
| Interesting. Whenever I meet something with a boolean behaviour
| I already decide upfront it will be easier and less time
| consuming to test accordingly instead of building a mental
| model. However I have no problem to model tree searching or
| a-star stuff. It just seems I never developed neurons with just
| two outcomes.
| xtagon wrote:
| See also the phenomenon of it always taking 3 tries to plug in
| USB the correct way
| mewpmewp2 wrote:
| Just 3? I wonder now if I'm inexperienced.
| idiotsecant wrote:
| Or in the bad days of micro usb on the third try you just
| force it in the wrong way and destroy the port.
| datameta wrote:
| This is especially common with a fresh USB port. I learned
| why recently from the book Open Circuits: The Inner Beauty of
| Electronic Components. There is a mechanical component that
| is more stiff before being used, which can lead one to think
| that they simply had the USB connector the wrong way around.
|
| I highly highly recommend the book by the way, to anyone on
| HN. Goes all the way from mechanical components to resistors,
| nixie tubes, CMOS sensors, processors etc. Excellent
| photography that reveals the internals, along with operation
| explanations and history for each component.
| herbcso wrote:
| That looks amazing! I immediately bought it, thanks for the
| recommendation!
| CamperBob2 wrote:
| I mean, any physics teacher will tell you that all fermions
| have spin 1/2, so I don't know why people are so confused by
| USB.
| GianFabien wrote:
| I've never tried to plug a fermion into a USB port.
| JoeCortopassi wrote:
| Fun fact: part of the licensing agreement to use USB, is to
| have the usb symbol on top of the connector. So unless you're
| using a cheap unlicensed cable, look for the symbol facing up
| and you'll always be correct
| j5155 wrote:
| ...unless, of course, the port is upside down/sideways ;)
| MadnessASAP wrote:
| As somebody who has practically no post-secondary and just
| likes to tinker in the garage. I thought it might be nice to
| get an education of some sorts so I could stop wasting time
| doing stuff like flipping signs till it works.
| corethree wrote:
| Is there a way to model this theoretically? Or is it always
| trial and error?
|
| I mean I realize you have to test the thing for "bugs" just
| wondering if a theory to perfectly model it is even possible.
| dgoldstein0 wrote:
| I think it's possible. But you'd have to be really careful
| with your equations, then have to be really careful to know
| which direction is positive in each signal and make sure to
| make the wiring and/or math match that. I can see why some
| trial and error would be easier than completely rechecking
| things when they don't work.
| corethree wrote:
| Does anyone know what I have to learn to "know" about this
| theory? Is it control theory and classical mechanics?
| YZF wrote:
| Pretty much yes. I expect the heavy lifting is just math.
| dutchkiwifruit wrote:
| Some things certainly can be modelled, but for others it is
| easier to simply try. For example, will applying a positive
| current to the motor make it spin in the clockwise or
| counterclockwise direction? It really depends on the
| behaviour and configuration of the motor controller, and in
| this case it was easier for me to just try.
|
| The trick is to do these tests at a sufficiently low level,
| because that's usually where these issues are, in my
| experience.
| lupire wrote:
| Of course. The OP was modeling it theoretically, but making
| mistakes.
| ryandrake wrote:
| A lot of engineering is ensuring you're making an even number
| of sign errors.
| idiotsecant wrote:
| I just want you to know how hard I'm going to steal this and
| pretend I invented it when people think its clever.
| ryandrake wrote:
| I'm doing the same thing. I didn't[1] invent it either.
|
| 1:
| https://twitter.com/id_aa_carmack/status/419313776463077377
| littlestymaar wrote:
| Carmack didn't invent it either, my physics teacher was
| saying that a lot 17 years ago so it's clearly a common
| thing.
| beebeepka wrote:
| had you not mentioned that, we might have gotten another
| fast inverse square root origin investigation
| lupire wrote:
| fast (multiplicative) _inverse_ square root.
| beebeepka wrote:
| autocorrect or dyslexia. whoever wins, i lose
| gattilorenz wrote:
| a possible source is in the replies to that tweet:
| https://twitter.com/RobbieBC/status/419324772754132992
| littlestymaar wrote:
| Honestly it wouldn't surprise me if it had been invented
| multiple times independently, it's just too obvious to
| anyone that has had to deal with calculation.
|
| (But thanks for sharing what us without a Twitter account
| cannot see otherwise anymore...)
| ReptileMan wrote:
| It was common saying 30 years ago when we were preparing
| for IT Olympiads in Eastern Europe - if you do even
| number of errors chances are your program will work ok.
| mensetmanusman wrote:
| We would joke in physics class that you either need to
| memorize the right-hand rule; or if you were right handed
| while doing the test, the negative left-hand rule.
|
| (because students would often make the mistake while
| holding their pencil during the exam of how to calculate
| the curl)
| dekhn wrote:
| also known as "a fortuitous cancellation of errors"
| malux85 wrote:
| Same in finance!
| LorenPechtel wrote:
| I spent many days trying to troubleshoot some HP/GL2 plotter
| code in the distant past. I eventually concluded that the real
| problem was with the implementation--I was working with code
| that was written by others and went a little crazy with
| coordinate transforms. Oops--worked as expected on one non-HP
| plotter. Drew the image inverted on a HP plotter. The HP
| implementation appeared to break if you flipped the world too
| many times. That was a *long* time ago, my memory is fuzzy by
| now.
|
| (And in later days I saw a firmware update for a laser printer
| cause it to spew gibberish when fed embedded HP/GL2 code. This
| was in the era where there were still DOS programs running
| under Windows and somebody didn't check that it still worked
| right.)
| dfee wrote:
| Is there a term for this systematic approach? I do it too, in
| software, and hone in on the right behavior using unit tests -
| especially to account for idiosyncratic off by one errors.
|
| Basically: get the structure right and then re-align the
| implementation to meet the expected behavior.
| oconnor663 wrote:
| Guess and check :)
| Tempest1981 wrote:
| HL? (human learning)
| ilayn wrote:
| Multimeter and basic input output testing is your
| underappreciated friend.
| neom wrote:
| Great art. This other thing he built is totally different, but
| just as fun to look at:
| https://www.youtube.com/watch?v=P9jyNIWsRvI
|
| I love engineers who make art _so much_.
| amelius wrote:
| I wouldn't say this other project is totally different. In
| fact, he can probably easily combine the two!
| neom wrote:
| It would be fun if the LEDs changed or did something special
| based on the rotation.. :o
| dutchkiwifruit wrote:
| This is definitely something I'm thinking about doing! I
| would ideally like to keep the reaction wheels visible
| though. Putting LEDs inside the wheels for a persistence of
| vision effect might be cool.
| sorenjan wrote:
| I remember seeing his M&M sorting machine several years ago:
| https://www.youtube.com/watch?v=ceGlMV4sHnk
| MOARDONGZPLZ wrote:
| This is extremely cool. Would love one that separates M&Ms
| from Skittles, which is a constant problem.
| almostnormal wrote:
| Even the sorting by color would be useful if Van Halen was
| still touring.
|
| https://m.youtube.com/watch?v=_IxqdAgNJck
| layer8 wrote:
| Now make it operate silently so that I can actually put it in
| my living room. ;)
| uint8_t wrote:
| If you like this, you are sure to love Jacob Tonski's "Balance
| from Within," a 170-year-old couch outfitted with reaction
| wheels so that it stands up improbably on one leg.
|
| Eventually, the reaction wheels max out and the couch falls
| over, exploding like... well, an interpersonal relationship if
| you ask the artist; but lately, it's hard not to see politics.
|
| It was recognized by Prix Ars Electronica, a very high honor
| for this genre of art.
|
| Video: https://www.youtube.com/watch?v=uQRP-b68fnE Article:
| https://ars.electronica.art/aeblog/en/2014/07/02/auf-der-suc...
| drBonkers wrote:
| Wow, I deeply want the cube and this couch. How much do you
| think it would cost to make the couch? How dangerous are
| these objects if one of the reactive wheels fails? I imagine
| if one was to fail, the object could be violently launched
| across the room.
| s0rce wrote:
| Do you mean a piece of the reaction wheel getting thrown
| across the room? You could shield that with something like
| they do on jet engines to avoid turbine blades being
| launched through the fuselage. I think the object itself is
| heavy enough compared to the energy in the reaction wheels
| that it would just fall over.
| newaccount74 wrote:
| I think a stainless steel reaction wheel is unlikely to
| break. Now those 3D printed reaction wheels using ball
| bearing balls for weight are another story:
| https://www.youtube.com/watch?v=AJQZFHJzwt4
| toss1 wrote:
| The cube? Not severe but enough to _definitely_ wear safety
| glasses when things are activated in development. The
| couch? That 's a fair amount of mass at a good height above
| floor level; definitely don't want to drop it on your body
| parts. Tje reaction wheels failing, Calc the max velocity &
| mass of the ring, and that'll give you an idea of the
| energy levels you're dealing with. I see nothing that would
| prevent me from doing either project, just enough to take
| good ordinary safety measures. Start on much smaller
| projects, enjoy the builds, and by the time you get to the
| cube & couch, you'll be able to estimate all that you need.
|
| Also, when you have a question in development, remember:
| One test is worth a thousand opinions (especially re. your
| own opinions).
| dutchkiwifruit wrote:
| I didn't know about this, but it's great! It makes me wonder
| whether I should come up with some kind of funny enclosure
| for my cube now, haha.
| kibwen wrote:
| Very cool! I'd like to see one of these made into a permanent
| sculpture, where the battery is removed and energy is provided
| via the contact plate itself.
| neom wrote:
| We need to get the guy who made this one and Tony Rosenthal
| together, unfortunately, however, Tony is dead.
|
| https://en.wikipedia.org/wiki/Tony_Rosenthal
| crazygringo wrote:
| That Alamo sculpture was the first thing I thought of! Fun
| fact: it spins, even though that was never intended. [1]
|
| Making a public sculpture size version seems really cool on
| the one hand. On the other hand, it seems incredibly
| dangerous if it could crush someone to death if the power or
| electronics failed...
|
| [1] https://en.wikipedia.org/wiki/Alamo_(sculpture)
| crazygringo wrote:
| I'm sure this is a dumb question because I never studied
| electrical engineering, but can you supply power with just a
| single point of contact? Rather than the two contacts/wires
| that wall plugs and batteries have? (And is a contact plate
| even safe?)
|
| Or would wireless power be the way to go, the same way we
| charge our phones these days? Could you fit a large enough coil
| close enough in the tip?
| philipwhiuk wrote:
| Can someone explain the reason for the massive font-size on the
| website?
| vdaea wrote:
| It's the "twentytwentyone" theme for wordpress, which was the
| default during... twenty twenty-one. Maybe he installed
| wordpress then and didn't bother changing the theme or liked it
| as it is.
| hanspeter wrote:
| Preemptively saving your Cmd+plus fingers from unneeded
| exercise.
| enjoyitasus wrote:
| The OA
| renewiltord wrote:
| Haha this is great, dude. Man it looks so well machined too.
| johanneskanybal wrote:
| Well I need one.
| stuaxo wrote:
| What a pleasing object.
| lh7777 wrote:
| > I plan to add mechanical brakes to the reaction wheels...This
| enables jump-up manoeuvers which in turn enable the cube to get
| to its equilibrium position on its own.
|
| Looking forward to this -- I always thought that was the coolest
| part of the Cubli project. Here's a video:
| https://youtu.be/n_6p-1J551Y?t=92
| darzu wrote:
| Amazing. Now it just needs a nice wood enclosure and matching
| induction charging pedestal. Kickstarter please take my money!
| __MatrixMan__ wrote:
| It makes me wonder if there's a better shape than a cube for
| this. You'd want to be non-circular to walk up things, but
| you'd want a circular edge for rolling down them. I'm imagining
| something like two hoops forming a sphere: rotate 90 degrees to
| switch between roll mode and walk mode.
| dutchkiwifruit wrote:
| That's an interesting idea. I have no good answer to your
| question, but something like a dodecahedron comes to mind, as
| a 'trade-off' between a cube and a sphere.
| javajosh wrote:
| In middle school I imagined a toy that would be a top with a
| similar mechanism as this cube. It could spin it's outer
| shell and then tilt and engage a "wheel" hoop, just a bit
| above the the tops tip, exchange some of of it's angular
| momentum for linear, right itself and build up angular
| momentum again. This would enable a fully enclosed, no
| external moving parts RC vehicle.
|
| It seems such a thing is possible now.
| mavili wrote:
| Impressive work! Some people have all the time in the world it
| seems!
|
| That said, it's not really "designing" if you're "building"
| something that already exists, is it?
| mavili wrote:
| Haha lol. Downvotes for saying "building" is not "designing".
| Why? Seriously people are so open-minded , very tolerant, just
| as long as you don't upset their feelings. Hahah
| smolder wrote:
| Shirts and pants have existed a long time, but clothing
| designers still design new ones. This isn't an exact copy of
| someone else's, it just uses the same principles, so yes, it is
| "designed".
| mavili wrote:
| You would say "I designed a t-shirt" not "I designed a
| clothing that has short sleeves".
|
| It could just be a casual title, guy probably didn't even
| mean to title it that way but he probably didnt think about
| it too much. But to downvote because I point out something
| factually incorrect is just absurd.
| maelito wrote:
| Makes me think to the Brennan monorail train.
|
| Very interesting video
| https://www.youtube.com/watch?v=kUYzuAJeg3M.
| beoberha wrote:
| I very much enjoy my career as a software engineer, but man
| there's a side of me that wishes I had studied something where I
| could even begin to build something like this. Super super cool!
| cuu508 wrote:
| You can learn all of this on your own! Like most of us learned
| programming ;-)
|
| Probably don't start with a self-balancing cube as the first
| project though. Get an Arduino or ESP board, make some leds
| blink and go from there.
| szundi wrote:
| Completely true and good advice
| stavros wrote:
| Yep! A self-balancing cube can definitely be your sixth
| project, though.
| YZF wrote:
| Sometimes taking a big challenge can accelerate learning.
| As long as you're not giving up ;)
| dylan604 wrote:
| Arduino + LED = Hello World for electronics.
|
| Find a project online that tickles your fancy, and then
| recreate that. If your thing doesn't work, you _know_ it is
| something you did incorrectly as the project has been built
| successfully by others. During the course of that project,
| you will pick up on so many little things.
|
| As an example, I had a project with more buttons than pins.
| Just something as simple as adding a few resistors to each
| button allows multiple buttons to be connected to the same
| pin. You just have test the voltage to know which button.
| Sounds simple, but I learned it from someone else's build.
|
| Nobody likes walking through tutorials for tutorials sake,
| but it's still useful and rewarding if you can build
| something functional as a tutorial.
| moffkalast wrote:
| Here's a handy guide ;)
|
| https://twitter.com/thepracticaldev/status/76048012124142796.
| ..
| A4ET8a8uTh0 wrote:
| Hah. That hit home. But now I have a kid and we are slowly
| starting to delve into things. It is oddly fun to explore
| this realm together.
| devsda wrote:
| As a fellow developer I feel the same but then when I realize
| that the cost of building something cool like this as a hobby
| is very high(for me at-least), I feel like we are lucky enough
| to have picked a field where the cost of experimenting is close
| to zero.
|
| As a middle ground, I've settled on home automation & hobby
| electronic projects with some micro controllers like esp32, rpi
| pico etc. It's worth a try for anybody itching to build
| something tangible.
|
| PS: the total BOM cost for this cube project was around 2500
| Euros.
| dylan604 wrote:
| > PS: the total BOM cost for this cube project was around
| 2500 Euros.
|
| Somethings are purchased in packs of 10 even when needing 1
| type of things happen too, so sometimes you have to divide
| the price by numbers used. Your comment also suggest you
| consider that nothing was necessary to repurchase or that the
| final BOM wasn't the 3rd iteration of which items were
| actually used in previous attempts. Pure R&D type hobby
| projects can be oh so much more expensive, but oh so much
| fun.
| weaksauce wrote:
| yeah just the motors alone were 471 euros and the controller
| boards were about 300 euros... this is a spendy project
| thimp wrote:
| It was always cool. Until you find the only jobs on the market
| were ones that involve making machines that kill people. That's
| what happened to me. YMMV.
| noman-land wrote:
| I know this is easy for me to say but I really want to
| encourage you and other hardware people to innovate on
| extremely cheap consumer facing commodity p2p/mesh
| communication devices. I've been teaching myself electronics
| and RF to try to be able to meaningfully contribute.
|
| It's dumb that we have these super computers in our pockets
| with long range antennas and in order to talk to each other
| they have to go through central intermediaries and paid
| access.
|
| I want ad-hoc geographically local connectivity without
| service providers.
| thimp wrote:
| That's a pipedream. Our current intermediary run cellular
| networks pretty much replaced all our previous
| infrastructure in that space because there are far fewer
| compromises to end user experience. Secondly, your phone
| doesn't have any long range antennas in it.
|
| Do some research on VHF/UHF amateur radio. That'll give you
| a primer on why this is hard. Think line of sight,
| repeaters, traffic management.
|
| Our current infra, even if it is paid, is cheap and
| miraculous.
|
| Edit: I had a ham license once (probably still do), built
| VHF transceiver, only had asshats to talk to on it
| (locality related not technical).
| esafak wrote:
| Wireless ad hoc networks came and went two decades ago.
| Perhaps they'll rise again but I wouldn't bank my career on
| it.
| Consultant32452 wrote:
| The closest I've heard of to something like this is some
| autist creates a low cost mesh internet connection for his
| neighborhood, then you could use VOIP on top of that.
| paganel wrote:
| Unfortunately most of today's software is also going down
| that route, if not necessarily killing people then most
| likely making their lives a lot more nightmare-ish. AI is a
| very good example of that.
| thimp wrote:
| That is exactly why I am heading out of the industry. I
| have little faith in the direction and want nothing to do
| with it any longer.
| Consultant32452 wrote:
| I was amused by the fact that in the same week that AI
| generated fake nudes of Taylor Swift was hitting news
| headlines another AI tool which puts clothes on e-girls
| pics also popped up on my radar.
|
| The internet is amazing and stupid.
| amelius wrote:
| You could instead work on a robot performing surgery ... Just
| one example.
| GianFabien wrote:
| The word "engineer" origin (from Oxford Dictionary):
|
| Middle English (denoting a designer and constructor of
| fortifications and weapons; formerly also as ingineer ): in
| early use from Old French engigneor, from medieval Latin
| ingeniator, from ingeniare 'contrive, devise', from Latin
| ingenium (see engine); in later use from French ingenieur or
| Italian ingegnere, also based on Latin ingenium
|
| Would be great if we had a less war-like derived word for our
| profession.
| s0rce wrote:
| A big portion of this is software and the rest you could
| certainly learn. Although I suspect if this was you day job you
| might not want to come home and build the same stuff...
| mseepgood wrote:
| In which day job does one build cubes balancing on the
| corner?
| s0rce wrote:
| Satellites mostly. Possibly missile guidance and then more
| general applications of controls.
| noman-land wrote:
| https://www.adafruit.com/ is an amazing resource. The tutorials
| are excellent and the products and video presentations of them
| are really great. Basically every single product has
| accompanying videos. It's very easy to spend some $$$ there.
| geor9e wrote:
| There is something a lot more healthy-feeling about tinkering
| in the shop using your hands, versus staring down a panel of
| colorful monospaced ascii. But the individual contributor MechE
| career plateaus in pay around $170k. There's no L7 or whatever
| pay scale. Seeing total compensation in the $300k+ range is
| unheard of. In software you find them all over. I'm sure
| there's rare exceptions but you get the gist.
| matthewtse wrote:
| I felt the same yearning. I found a creative outlet in
| hardware, that still furthers my software engineering career,
| by building a custom mechanical keyboard to improve coding
| speed, accuracy, and efficiency.
|
| https://www.reddit.com/r/ErgoMechKeyboards/comments/hj0q8x/f...
| pradn wrote:
| This is exactly the sort of artifact you expect a wizard to have
| floating above their hand on a fantasy pulp's cover, circa 1955.
| jedilance wrote:
| I was hoping for a DIY kit available until I saw BOM costs around
| 2.5k
| moffkalast wrote:
| Well this is such an old project idea that they are already
| being sold on aliexpress both in complete form for $500 and $50
| per torque axis if you want to make one from scratch. Just
| search up cubli.
| SeanAnderson wrote:
| I've got a floating planter (not this model, but similar:
| https://www.amazon.com/BandD-Floating-Plant-Pot-Levitating/d...).
|
| It would be cool to combine these techs. Maybe have a floating
| floor that the cube then balances on or something to that effect.
| dutchkiwifruit wrote:
| That would be cool. I thought about balancing one cube on top
| of another balancing cube, but sadly I've only got one.
| ijhuygft776 wrote:
| Here is one from 10 years ago that can jump up, balance, and
| 'walk': https://www.youtube.com/watch?v=n_6p-1J551Y
| deadbabe wrote:
| How large could these cubes scale?
| dutchkiwifruit wrote:
| I'm not sure! You could probably at least double the rib length
| if the wheels are scaled accordingly. I can however answer the
| opposite "how small" question to some extent by linking to this
| really cool project: https://youtu.be/hI5UDKaWJOo
| __MatrixMan__ wrote:
| Call me reckless, but I'd totally pay to climb a bigger one, with
| holds along the edges. I just wanna feel how it responds to my
| movements.
| pravint wrote:
| This is so beautiful work ! Loved it !
| markdog12 wrote:
| Imagine showing Archimedes this device.
| anonymouskimmer wrote:
| I pictured one of three things:
|
| 1) A "cube" that isn't really a cube in that the corners aren't
| points.
|
| 2) A cube designed to balance on the corner of a wall.
|
| 3) A cube with varying densities such that it will balance on a
| corner.
|
| I did not picture a mechanical device.
| EGreg wrote:
| We've reached a point where machines can do pretty much
| everything better than humans and animals too, even without AI.
| Because people add solutions to problems and if they're better
| than previous ones, then it's downloaded to all the machines
| which perfectly run the software. Self-driving card etc.
|
| No animal can compete with the accuracy, reaction speed, etc.
| Racing Drones will be able to fly better than 99% of human
| operators. Cars will be able to drive better than 99% of human
| operators. And consistently.
|
| Google already gives direction better. Trading bots trade better.
| They are preferred by people and corporations, respectively.
|
| I wouldn't be surprised if computers can brute-force better
| scientific theories just by being fed motions of stars or other
| data. Like deducing Kepler's laws in 2 minutes and then going
| much much further, into laws that use 19283-dimensional vectors
| and are 99.9% of the time predictive.
|
| Monte Carlo Tree Search has done very well with chess, with
| AlphaZero beating all human-designed programs like Rybka, and
| playing much more elegant chess too.
|
| Where we need AI models is training on human-produced data (art,
| text on the internet, etc.) And there, it can be trained to
| maximize various metrics, including human satisfaction, or actual
| investment into an enterprise, and soon -- laughing at jokes, or
| agreeing to go out with someone romantically, etc. Just pick the
| stuff that works the best, and show it to humans as a
| superstimulus.
|
| In addition, the models are developing "understanding" of the
| latent space, the way a student in a classroom would develop this
| from listening to the professors explain stuff (rather than do
| experiments themselves). The latent space, thanks to humans,
| models the real world quite well, from a human perspective, and
| the computers can become polyglots and polymaths... ALL of them.
| Just download some compressed model weights onto a small
| computer, and it becomes more knowledgeable about topics than any
| human. And just like other software, the weights can be improved.
|
| But the next level is Swarms. Swarms of bots in online accounts
| at online platforms and communities will be able to optimize
| "reputation" points that they accumulate from existing humans in
| the communities (social capital). By doing this 24/7, and
| mimicking timing of humans etc. they can eventually (in
| aggregate) command far more reputation than any set of humans.
| They can also coordinate over long periods of time, as sleeper
| accounts, and eventually undertake any reputational attacks,
| including and up to having a person's own friends turn on them,
| ruining a famous person's reputation, having them convicted of a
| crime, or even foment a war etc.
|
| Whether or not humans are behind these directives at that point
| will be irrelevant. It's a bit like giving everyone atomic bombs
| or the ability to create novel viruses, except online. Someone's
| bound to misuse it. And because the swarms are so destructive and
| able to blend in, the internet will become a Dark Forest and
| people will try to retreat into real-life communities, where they
| will try to eliminate bots by having people show up periodically
| at events, but never completely succeed (because these same
| people will run bots on their own accounts).
|
| Already for years, corporations have been deploying algorithms to
| optimize people's addiction to TikTok, Instagram etc. with
| predictable effects of depression in teens, anger in adults
| arguing politics, etc. And that was _before_ AI.
|
| I wrote about this here in LA Weekly:
| https://www.laweekly.com/restoring-healthy-communities/
| ponector wrote:
| That is not true. Machines can do things better only in strict
| environment.
|
| Self driving car in Las Vegas is relatively easy. How about
| tight curvy streets of Rome?
|
| And what about medical machines or sex machines. I doubt they
| are better then human.
| EGreg wrote:
| That's what people say right before the exponential function
| (or rather, X^n) elipses them
|
| "Sure, the machines can do X really well, but what about Y"
|
| Y is just X with more variables. The machines will be able to
| do better than 95% of humans in a couple years, and then
| eventually better than all humans. But doing better than 95%
| already means they will be preferred everywhere.
|
| And the swarms is the key!
| Invictus0 wrote:
| It's a shame that cubli wasn't open sourced in the first place.
| Academics need to do better than just publish papers
| dutchkiwifruit wrote:
| Agreed. If only to enable others to reproduce and improve on
| the work.
| litoE wrote:
| Just out of curiosity: do the flywheels actually stop and rotate
| slowly in either direction or is it just an artifact of the
| video?
| ElectricalUnion wrote:
| One of the optimizations that is employed to make the whole
| thing possible is reducing flywheel rotational speed whenever
| possible. Otherwise, as the video says, the reaction wheels get
| saturated and you lose control over that saturated axis
| rotation.
| dutchkiwifruit wrote:
| Yes, the reaction wheels normally rotate very slowly.
| wwarner wrote:
| really so beautiful. the writeup really revved up my imagination,
| thinking about how the wheels slow and reverse direction to
| change and then maintain equilibrium, and thinking about how
| wheels like this control the orientation of the hubble and jwst.
| wojtczyk wrote:
| Thanks for sharing! Awesome project
| crazygringo wrote:
| Wow, watching that video is _wild_. It 's the closest I've ever
| found myself to thinking, well that's just _magic_. The way it
| responds to being pushed around, it 's almost like experiencing
| magnetism for the first time, only now it's as if it's a whole
| new force. It almost seems like it's _alive_ , actively
| maintaining its equilibrium and resisting changes from its
| environment. Throw a literal tomato on it and it just _adapts_ ,
| not unlike the way our bodies do to changing loads.
|
| I can't wait until smaller mass-produced versions are sold on
| Amazon for $50, however many years from now that is! I would just
| love to play with something like this.
| dutchkiwifruit wrote:
| Your comment makes me smile. Thank you! :)
| neom wrote:
| I think you've got a startup on your hands young man. ;)
| fisian wrote:
| I really agree that some control engineering applications can
| feel like magic.
|
| When I learned programming, I thought "Wow, I can tell a
| computer anything I want, as long as I take the time to program
| it."
|
| I have a similar feeling about control theory, just that it
| feels like you're "programming" the laws of physic, modifying
| how reality works.
| tamimio wrote:
| Not to downplay software engineering, but any project that mixes
| hardware and software together is always better and cooler in my
| opinion, great work!
| pests wrote:
| James Burton on YouTube makes a lot of self balancing robots with
| different configurations and balancing techniques.
| stuart73547373 wrote:
| strong plug for onshape instead of fusion360
| Animats wrote:
| Nice.
|
| That stainless steel work is very nice. I didn't know PCBway did
| CNC machining. eMachineShop has been around for two decades, but
| now more companies are offering online CNC, which may bring
| prices down.
|
| He wants to add brakes, so he can spin up a wheel, apply the
| brake hard, and get enough of a change in angular momentum to
| bring the thing upright. I wonder if eddy current brakes would
| work for that. More elegant and quieter than friction brakes.
| Actually, just shorting the motor might work.
| dutchkiwifruit wrote:
| I've considered various concepts for the brake design and think
| the way forward is to use friction brakes. The original Cubli
| uses bicycle brake pads, but this has its disadvantages. I'm
| thinking about using a (possibly bidrectional) band brake for
| my cube, similar to the one used in the "M-Blocks" [1]. Based
| on this video and the associated research paper, I'm quite
| optimistic about this kind of brake.
|
| [1] https://www.youtube.com/watch?v=hI5UDKaWJOo.
| Panzer04 wrote:
| I suppose there are limits to the size and power of the
| motors and controllers you want to use, but those inrunners
| are probably not ideal either, right? I wonder if you could
| use an oversized hobby outrunner and achieve the same effect
| (probably with a large controller as well)
|
| Also, even if most hobby motors do not specify Nm/A, they
| usually give KV, which is actually the same value but shown
| in a different form :)
| c-smile wrote:
| What if to keep it standing for the whole day?
| altspace wrote:
| Reminded me of the red cube in NYC
| https://publicdelivery.org/isamu-noguchi-red-cube/
| andrewp123 wrote:
| This is really cool. Would love to see a basic analysis of the
| physics - I know it's just basic angular momentum and torque. Are
| reaction wheels somehow intuitive and don't require you to think
| about these things?
| dutchkiwifruit wrote:
| Most of the dynamics and kinematics involved are thoroughly
| discussed in the research work that has been published by the
| authors of the original Cubli! For example:
| https://ethz.ch/content/dam/ethz/special-interest/mavt/dynam...
| lovegrenoble wrote:
| You have to make fundraising to produce it on
| https://www.kickstarter.com
| geor9e wrote:
| Now put some of those reaction wheels in one of these, to give
| them lateral self balancing
| https://alienrides.com/collections/electric-unicycles
| CodeWriter23 wrote:
| My kind of crazy mf.
| matthewtse wrote:
| Just subscribed to your YouTube channel, hope to see more
| Mechanical Marvels from you! It's rare to feel an unstoppable
| childlike smile creep onto my face, the smile of experiencing
| joy+wonder, and I felt that today.
|
| Also super impressed by the build quality and the welds you made
| for this hobby project.
| dutchkiwifruit wrote:
| Thank you!
| syntaxing wrote:
| As a former MechE, those parts look like it cost a pretty penny
| but damn, the results are worth it. Naively, you should be able
| to plug figure 21 into simulink to get the tuned constants.
| Though to be honest, getting the system constants will probably
| take just as much time and for a one off piece that's for fun,
| hand tuning is more than fine.
| dutchkiwifruit wrote:
| Fusion 360 calculates things like moments of inertia and
| weight, and this was very helpful since the controller requires
| these parameters to convert control inputs to torques, for
| example. I still had to tune the controller gains, of course.
| (Which I did by hand.)
| syntaxing wrote:
| Is there anyway to tune the controller gains beforehand? Also
| if you don't mind me asking, how much did everything cost
| you? This looks super fun and I'm debating to build one.
| tharakam wrote:
| It's so beautiful! Love it!
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