I wonder what the cheapest possible build for something like this is, if you loosen enough constraints - let&#x27;s say, if we allow it to be externally powered, and agree that size doesn&#x27;t matter.Would it be cheaper (and&#x2F;or safer) to build a larger one, allowing for larger-but-slower flywheels? Could you make one out of a couple of scrap bicycles?

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.

Same. Immediately checked if it is for sale (apparently it costs $2500 if you do it yourself).

I&#x27;m actually more enamored with the cool look of the thing rather than the fact that it can balance.

It would lose its form factor of a pencil.

If the pencil can be very short, just put this cube on top of it.

What about a coin that always lands on its edge?

No worries: <a href="https:&#x2F;&#x2F;youtu.be&#x2F;woCdjbsjbPg" rel="nofollow">https:&#x2F;&#x2F;youtu.be&#x2F;woCdjbsjbPg</a>

Next I want to see a pencil that balances itself on its tip.

Probability courses would be funny with that thing.Roll the dice.

Cool functionality aside, it looks beautiful.

As mentioned in the article, reaction wheels are the standard method used to control satellite attitude.

Totally does work, lots of spacecraft use reaction wheels to control attitude.

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.

&gt; Wondering if this technology can be used to control spacecraft attitudeIt can indeed, and is already used in the wild today!<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Reaction_wheel#Examples_of_spacecraft_using_reaction_wheels" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Reaction_wheel#Examples_of_spa...</a>

Thank you! The weight of each wheel is approximately 220 g, whereas the total weight of the cube including wheels is 1700 g.

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?

True, but for something like this, would it work with a magnet?

If you&#x27;ve got 2 wheels side by side like a Segway, all you need is the IMU and those 2 wheels.

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.

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.

&gt; or are there implementations that don&#x27;t require spinning wheelsTons of different implementations out there for balancing. Maybe the most common one is the one we humans use, which requires zero wheels :)

This is cool. Is this how robots normally balance themselves, or are there implementations that don&#x27;t require spinning wheels?

Maybe some thin plexiglass around it would be fine - not sure if it would compromise the mechanism though.

How about just plexiglass sheets mounted on the 6 faces of the cube? With screws so they can be removed easily.

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.

My first reaction when I see one of these is &quot;where can I buy one?&quot;  And then I realize that it&#x27;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.

Why are you on Hacker News instead of practicing your software engineering skills? -50 points for Griffindor!

If you feel bad about yourself because of that, think of it not like something personal, it&#x27;s a lot connected to the environment you are from, and some factors cannot be controlled.It&#x27;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)

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&#x27;t have the &quot;whoa&quot; factor, but it also didn&#x27;t cost $2500 to build (not including the years [decades?]) spent learning.

It isn&#x27;t so much discouragement. And it&#x27;s a lot more like a great painter who would listen to a pianist masterpiece, and know very well achieving that level of skill in that totally different art field would be almost impossible = time is limited, would involve giving up the mastery or continue to improve in the visual artistry.It isn&#x27;t someone much better at something. It&#x27;s someone much better at something entirely different yet quite related.It doesn&#x27;t change what one can do that&#x27;s true. Comparison with oneself is mentally healthier for sure. But humans compare themselves with who they can see, the internet gives us a view of what virtually everyone is capable of.

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.

You could start by following basic tutorials and getting kits from places like adafruit. Many of them don&#x27;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.

The thing to do here would be to remove two dimensions first, it makes things _lot_ easier, and you can use off the self&#x2F;hand made parts.

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.

+ intensive in terms of energy usage + needed a second gyro to feel like you are standing in a flat environment.

Isn&#x27;t it more likely that idea got abandoned because a failure of the balancing system would be catastrophic?

Details for the curious: <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Gyro_monorail" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Gyro_monorail</a> <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=kUYzuAJeg3M" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=kUYzuAJeg3M</a>

The gyroscopic action of the cube&#x27;s momentum wheels must make the control algorithms quite entertaining.

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: <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Control_moment_gyroscope" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Control_moment_gyroscope</a>

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.

You are not alone. I&#x27;ve come to terms with the reality that every controller I&#x27;ve designed and implemented will always need a good amount of unit test coverage to ensure proper behavior (like signs and directions)...

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.

Just 3? I wonder now if I&#x27;m inexperienced.

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.

I mean, any physics teacher will tell you that all fermions have spin 1&#x2F;2, so I don&#x27;t know why people are so confused by USB.

Fun fact: part of the licensing agreement to use USB, is to have the usb symbol on top of the connector. So unless you&#x27;re using a cheap unlicensed cable, look for the symbol facing up and you&#x27;ll always be correct

Or 4 when it turns out you&#x27;re trying the HDMI port instead.

The holes in the contact on the cable should be up when plugging into the laptop

People think the USB-A port looks symmetrical. The way I do it is I look inside the connector and note which side the pins are before trying to plug it in 3 times.

See also the phenomenon of it always taking 3 tries to plug in USB the correct way

EE is very rewarding. I think it is only second to physics and nuclear eng in terms of how deep they go into physics.You also cover a wide array of topics, from hardware and how it works to a lot of systems programming (e.g: real-time operating systems, kernels, device drivers) some computer science theory (mainly automata theory and concurrency like petri nets) to signal processing which includes audio to heavy yet extremely beautiful math topics such as control theory.

I went through an EE associates program at my local community college after I’d graduated with a BA, purely because I wanted to know how to fix&#x2F;modify&#x2F;tinker with audio equipment. I went at night, part time, and it was easily one of the best experiences of my life. Like yourself, I had some amateur experience already, and as the gaps were filled I had at least 4-5 truly paradigm shifting moments where multiple concepts finally clicked together and whole swaths of the world suddenly made sense. I found elegant connections in the physics, familiar logic applications, and gained a lot of insight that I hadn’t expected, which helped reinforce my sense of just how little I will ever really know.Even though the purpose for taking those classes was largely personal, it’s materially contributed to my career in a lot of indirect ways (I’m an IT consultant and Linux sysadmin) by giving me a unique perspective for how things function on a much lower level than my colleagues who just have CS educations. I can troubleshoot Wi-Fi and signal transmission issues using spectrum and vector network analysis which makes everyone look at me as if I were a witch. I am comfortable disassembling and repairing equipment like scanners and commercial printers, with lots of moving parts and mains electricity that other techs won’t touch.All that said, I highly recommend attending an EE program, and even though you’ll feel like a big, wrinkled brain smart person—you will never stop turning it off and on again, bit-bashing, or sign flipping—all quite valid techniques for when the years of diligent study and experience loses out to fat fingers and poor eyesight.

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.

I think it&#x27;s possible.  But you&#x27;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&#x2F;or math match that.  I can see why some trial and error would be easier than completely rechecking things when they don&#x27;t work.

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.

Of course. The OP was modeling it theoretically, but making mistakes.

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 &quot;bugs&quot; just wondering if a theory to perfectly model it is even possible.

I just want you to know how hard I&#x27;m going to steal this and pretend I invented it when people think its clever.

also known as &quot;a fortuitous cancellation of errors&quot;

This reminds me of how one time in an interview, I realized I had an off-by-one error. Instead of actually trying to understand the source of the error, I just sped-run tweaking different values +&#x2F;- 1 until I got the expected result.In the moment I felt quite clever, but the interviewer apparently did not appreciate that technique.

This joke is used at the start of Abrash’s Graphics Programming Black Book, followed by “If you laughed, you’re a graphics nerd.” :D

The rest of engineering is doing very careful math and then multiplying everything by two just to be sure.

&quot;Now let&#x27;s assume our chicken is a sphere..&quot;

The tricky bit is when you have multiple interacting systems which see different combinations of those sign errors: it makes it a lot more important to know where all the sign flips should actually be. For example, it&#x27;s quite easy to make a PID controller where the D term is actually the opposite sign to the others.

Reminds me of one of my favorite lines of code:<pre><code> i = i - 2 &#x2F;&#x2F; because I&#x27;m bad at this</code></pre>

A lot of engineering is ensuring you&#x27;re making an even number of sign errors.

I spent many days trying to troubleshoot some HP&#x2F;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&#x2F;GL2 code. This was in the era where there were still DOS programs running under Windows and somebody didn&#x27;t check that it still worked right.)

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.

Multimeter and basic input output testing is your underappreciated friend.

This is precisely how I passed the lab portion of my Control Systems course in undergrad engineering.

There are satellites in orbit right now that have their reaction wheels harnessed backwards and have a x *= -1.0; &#x2F;&#x2F;DO NOT TOUCH in the codebase.Everyone does it, though usually you do the test before you duct tape it to the top of a few thousand kg of explosives and push the red button :)

When studying electrical engineering (during all the advanced control theory math and stuff) we were told that this is the official way to do it. If your PID controller doesn&#x27;t work at first, second or third attempt, you don&#x27;t run for your math books, you tweak it and try again until it works.

Quaternions are hard to get right, and impossible to get right the first time.<a href="https:&#x2F;&#x2F;twitter.com&#x2F;grapefrukt&#x2F;status&#x2F;1618517709767016450" rel="nofollow">https:&#x2F;&#x2F;twitter.com&#x2F;grapefrukt&#x2F;status&#x2F;1618517709767016450</a>

&gt; 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 &amp; signal processing (who ended up doing way more boring things), I always figured that I was doing that because I wasn&#x27;t experienced enough. Turns out I also had the sign wrong on that one all along!

It would be fun if the LEDs changed or did something special based on the rotation.. :o

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.

I wouldn&#x27;t say this other project is totally different. In fact, he can probably easily combine the two!

This is extremely cool. Would love one that separates M&amp;Ms from Skittles, which is a constant problem.

I remember seeing his M&amp;M sorting machine several years ago: <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=ceGlMV4sHnk" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=ceGlMV4sHnk</a>

Now make it operate silently so that I can actually put it in my living room. ;)

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.

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.

If you like this, you are sure to love Jacob Tonski&#x27;s &quot;Balance from Within,&quot; 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&#x27;s hard not to see politics.It was recognized by Prix Ars Electronica, a very high honor for this genre of art.Video: <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=uQRP-b68fnE" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=uQRP-b68fnE</a>
Article: <a href="https:&#x2F;&#x2F;ars.electronica.art&#x2F;aeblog&#x2F;en&#x2F;2014&#x2F;07&#x2F;02&#x2F;auf-der-suche-nach-dem-gleichgewicht&#x2F;" rel="nofollow">https:&#x2F;&#x2F;ars.electronica.art&#x2F;aeblog&#x2F;en&#x2F;2014&#x2F;07&#x2F;02&#x2F;auf-der-suc...</a>

Great art. This other thing he built is totally different, but just as fun to look at: <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=P9jyNIWsRvI" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=P9jyNIWsRvI</a>I love engineers who make art so much.

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] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Alamo_(sculpture)" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Alamo_(sculpture)</a>

We need to get the guy who made this one and Tony Rosenthal together, unfortunately, however, Tony is dead.<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Tony_Rosenthal" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Tony_Rosenthal</a>

I&#x27;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&#x2F;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?

Very cool! I&#x27;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.

It&#x27;s the &quot;twentytwentyone&quot; theme for wordpress, which was the default during... twenty twenty-one. Maybe he installed wordpress then and didn&#x27;t bother changing the theme or liked it as it is.

Preemptively saving your Cmd+plus fingers from unneeded exercise.

Can someone explain the reason for the massive font-size on the website?

Haha this is great, dude. Man it looks so well machined too.

Amazing. Now it just needs a nice wood enclosure and matching induction charging pedestal. Kickstarter please take my money!

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.

In middle school I imagined a toy that would be a top with a similar mechanism as this cube. It could spin it&#x27;s outer shell and then tilt and engage a &quot;wheel&quot; hoop, just a bit above the the tops tip, exchange some of of it&#x27;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.

It makes me wonder if there&#x27;s a better shape than a cube for this.  You&#x27;d want to be non-circular to walk up things, but you&#x27;d want a circular edge for rolling down them.  I&#x27;m imagining something like two hoops forming a sphere: rotate 90 degrees to switch between roll mode and walk mode.

Knowing and seeing how it works takes away a lot of the magic, but imagine finding a completely featureless whirring metal cube... that then jumps up onto an edge, then onto a corner, and starts spinning. And is capable of doing this on any random surface.I bet that would puzzle even most people who consider themselves familiar with physics and when the cube suddenly jumps back from a corner onto a face, clearly showing that the jumping isn&#x27;t just some hidden mechanism that extends, make some seriously consider the possibility of magic.

&gt; 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&#x27;s a video: <a href="https:&#x2F;&#x2F;youtu.be&#x2F;n_6p-1J551Y?t=92" rel="nofollow">https:&#x2F;&#x2F;youtu.be&#x2F;n_6p-1J551Y?t=92</a>

You&#x27;re confusing design with invention. People design new instances of existing classes of object all the time, from shoes, to cars, to shirts. We call this profession &quot;design&quot;, in fact. It&#x27;s what the OP did with the cube: designed one.

Haha lol. Downvotes for saying &quot;building&quot; is not &quot;designing&quot;. Why?
Seriously people are so open-minded , very tolerant, just as long as you don&#x27;t upset their feelings. Hahah

You would say &quot;I designed a t-shirt&quot; not &quot;I designed a clothing that has short sleeves&quot;.It could just be a casual title, guy probably didn&#x27;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.

Shirts and pants have existed a long time, but clothing designers still design new ones. This isn&#x27;t an exact copy of someone else&#x27;s, it just uses the same principles, so yes, it is &quot;designed&quot;.

I agree that &quot;design&quot; in the title is misleading. The main novelty of this cube is that it balances itself etc, and that was thought of and designed 12 years ago at ETH.Nonetheless, incredible work by the OP - &quot;I built a cube that balances itself&quot; is already extremely impressive

He didn&#x27;t invent it and doesn&#x27;t claim he did but he did design each and every part that could not be bought off the shelf as well as the final assembly. I&#x27;d say &#x27;design&#x27; is more than appropriate.

Impressive work! Some people have all the time in the world it seems!That said, it&#x27;s not really &quot;designing&quot; if you&#x27;re &quot;building&quot; something that already exists, is it?

Makes me think to the Brennan monorail train.Very interesting video <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=kUYzuAJeg3M" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=kUYzuAJeg3M</a>.

Yep! A self-balancing cube can definitely be your sixth project, though.

Arduino + LED = Hello World for electronics.Find a project online that tickles your fancy, and then recreate that. If your thing doesn&#x27;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&#x27;s build.Nobody likes walking through tutorials for tutorials sake, but it&#x27;s still useful and rewarding if you can build something functional as a tutorial.

Here&#x27;s a handy guide ;)<a href="https:&#x2F;&#x2F;twitter.com&#x2F;thepracticaldev&#x2F;status&#x2F;760480121241427968" rel="nofollow">https:&#x2F;&#x2F;twitter.com&#x2F;thepracticaldev&#x2F;status&#x2F;76048012124142796...</a>

You can learn all of this on your own! Like most of us learned programming ;-)Probably don&#x27;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.

&gt; 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&#x27;t the 3rd iteration of which items were actually used in previous attempts. Pure R&amp;D type hobby projects can be oh so much more expensive, but oh so much fun.

yeah just the motors alone were 471 euros and the controller boards were about 300 euros... this is a spendy project

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&#x27;ve settled on home automation &amp; hobby electronic projects with some micro controllers like esp32, rpi pico etc. It&#x27;s worth a try for anybody itching to build something tangible.PS: the total BOM cost for this cube project was around 2500 Euros.

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&#x2F;mesh communication devices. I&#x27;ve been teaching myself electronics and RF to try to be able to meaningfully contribute.It&#x27;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.

Unfortunately most of today&#x27;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.

You could instead work on a robot performing surgery ... Just one example.

The word &quot;engineer&quot; 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 ingénieur or Italian ingegnere, also based on Latin ingeniumWould be great if we had a less war-like derived word for our profession.

One sometimes gets to a second take on that: you don&#x27;t want to make machines that kill people, until invaders from another country ride into your country (or a country of your friends&#x2F;neighbors) and start killing, raping and torturing. And suddenly, as you feel frustrated and powerless, you realize that even though you don&#x27;t want to make machines that kill people, you pretty much have to, otherwise those people will come for you, your family and your friends.I thought humanity would grow out of senseless aggression in 2024, but here we are. And yes, I am basing this on a specific real-world example of a country invading another country right next to mine, and my specific thoughts and beliefs.

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.

In which day job does one build cubes balancing on the corner?

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...

<a href="https:&#x2F;&#x2F;www.adafruit.com&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.adafruit.com&#x2F;</a> 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&#x27;s very easy to spend some $$$ there.

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&#x27;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&#x27;m sure there&#x27;s rare exceptions but you get the gist.

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.<a href="https:&#x2F;&#x2F;www.reddit.com&#x2F;r&#x2F;ErgoMechKeyboards&#x2F;comments&#x2F;hj0q8x&#x2F;first_diy_keyboard_dactyl_manuform_5x6&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.reddit.com&#x2F;r&#x2F;ErgoMechKeyboards&#x2F;comments&#x2F;hj0q8x&#x2F;f...</a>

You totally can. This video [1] someone linked below comes with a github repo [2], it seems pretty straight forward to build this with access to a 3d printer and some basic electronics&#x2F;soldering skills. Probably a &lt;100$ for parts project? You also need a soldering iron and learn how to use it, but nothing of this is too hard for anyone technically inclined, especially if you have a hackerspace nearby where you can get a bit of help.[1] <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=AJQZFHJzwt4" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=AJQZFHJzwt4</a>
[2] <a href="https:&#x2F;&#x2F;github.com&#x2F;remrc&#x2F;Self-Balancing-Cube">https:&#x2F;&#x2F;github.com&#x2F;remrc&#x2F;Self-Balancing-Cube</a>

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!

This is exactly the sort of artifact you expect a wizard to have floating above their hand on a fantasy pulp&#x27;s cover, circa 1955.

<a href="https:&#x2F;&#x2F;a.aliexpress.com&#x2F;_EzMRNIv" rel="nofollow">https:&#x2F;&#x2F;a.aliexpress.com&#x2F;_EzMRNIv</a> €250 for one axis (edge) and €500 for a 3-axis (single point). There are a couple sellers &#x2F; designs.

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.

I was hoping for a DIY kit available until I saw BOM costs around 2.5k

That would be cool. I thought about balancing one cube on top of another balancing cube, but sadly I’ve only got one.

I&#x27;ve got a floating planter (not this model, but similar: <a href="https:&#x2F;&#x2F;www.amazon.com&#x2F;BandD-Floating-Plant-Pot-Levitating&#x2F;dp&#x2F;B091WYF4XF&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.amazon.com&#x2F;BandD-Floating-Plant-Pot-Levitating&#x2F;d...</a>).It would be cool to combine these techs. Maybe have a floating floor that the cube then balances on or something to that effect.

Here is one from 10 years ago that can jump up, balance, and &#x27;walk&#x27;: <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=n_6p-1J551Y" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=n_6p-1J551Y</a>

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: <a href="https:&#x2F;&#x2F;youtu.be&#x2F;hI5UDKaWJOo" rel="nofollow">https:&#x2F;&#x2F;youtu.be&#x2F;hI5UDKaWJOo</a>

It can be hard to commit to certain moves that you think you can do even when the wall is staying still.  I think having to commit to them even when you know it&#x27;s going to move would help with one&#x27;s head game when they went back to stable rock.

gonna be like climbing a wall of jello, or a mountain during an earthquake. fun thought experiment.

Call me reckless, but I&#x27;d totally pay to climb a bigger one, with holds along the edges.  I just wanna feel how it responds to my movements.

Anything that balances is mechanical, you will always end up moving something to compensate for being off center. For instance, you could have two fans spinning to pump air from one side of the device to the other but that would still be mechanical. You could do the same with fluid and so on. But all of it would eventually require a mechanical component to output the reaction force.Ion drives or selectively colored surfaces don&#x27;t have enough impulse to do the job, those are the only non-mechanical reaction devices that I know of, but maybe there are others that could work?

I had a McDonald’s toy that was a self balancing Superman on a point. Obviously this cube is something else in that it can move around but I wonder if it’s even possible to build a non mechanical cube that could balance on its point

I pictured one of three things:1) A &quot;cube&quot; that isn&#x27;t really a cube in that the corners aren&#x27;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.

That&#x27;s what people say right before the exponential function (or rather, X^n) elipses them&quot;Sure, the machines can do X really well, but what about Y&quot;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!

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.

We&#x27;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&#x27;re better than previous ones, then it&#x27;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&#x27;t be surprised if computers can brute-force better scientific theories just by being fed motions of stars or other data. Like deducing Kepler&#x27;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 &quot;understanding&quot; 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 &quot;reputation&quot; points that they accumulate from existing humans in the communities (social capital). By doing this 24&#x2F;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&#x27;s own friends turn on them, ruining a famous person&#x27;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&#x27;s a bit like giving everyone atomic bombs or the ability to create novel viruses, except online. Someone&#x27;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&#x27;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: <a href="https:&#x2F;&#x2F;www.laweekly.com&#x2F;restoring-healthy-communities&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.laweekly.com&#x2F;restoring-healthy-communities&#x2F;</a>

Agreed. If only to enable others to reproduce and improve on the work.

It&#x27;s a shame that cubli wasn&#x27;t open sourced in the first place. Academics need to do better than just publish papers

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.

Yes, the reaction wheels normally rotate very slowly.

Just out of curiosity: do the flywheels actually stop and rotate slowly in either direction or is it just an artifact of the video?

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.

I think you&#x27;ve got a startup on your hands young man. ;)

Your comment makes me smile. Thank you! :)

I really agree that some control engineering applications can feel like magic.When I learned programming, I thought &quot;Wow, I can tell a computer anything I want, as long as I take the time to program it.&quot;I have a similar feeling about control theory, just that it feels like you&#x27;re &quot;programming&quot; the laws of physic, modifying how reality works.

But in 10 years nobody has built a low-cost design right? Since OP has open sourced the build and software, that may change now.

&gt; I can&#x27;t wait until smaller mass-produced versions are sold on Amazon for $50, however many years from now that is!This is old as fuck btw..... checkout youtube for 10year+ examples...

OP is planning on implementing braking next, which will make the same capabilities available in this open source design.

In the old Cubli videos they go further, chaining together &quot;jumping up&quot;, balancing, and controlled falling to demonstrate locomotion!<a href="https:&#x2F;&#x2F;youtu.be&#x2F;n_6p-1J551Y?si=zvwORnuPZmgXw0S8" rel="nofollow">https:&#x2F;&#x2F;youtu.be&#x2F;n_6p-1J551Y?si=zvwORnuPZmgXw0S8</a>

Wow, watching that video is wild. It&#x27;s the closest I&#x27;ve ever found myself to thinking, well that&#x27;s just magic. The way it responds to being pushed around, it&#x27;s almost like experiencing magnetism for the first time, only now it&#x27;s as if it&#x27;s a whole new force. It almost seems like it&#x27;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&#x27;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.

Not to downplay software engineering, but any project that mixes hardware and software together is always better and cooler in my opinion, great work!

James Burton on YouTube makes a lot of self balancing robots with different configurations and balancing techniques.

strong plug for onshape instead of fusion360

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&#x2F;A, they usually give KV, which is actually the same value but shown in a different form :).

I wonder if shorting out the windings or even more extreme, reversing polarity on the running motor would have enough of an effect to cause the jump.

I&#x27;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&#x27;m thinking about using a (possibly bidrectional) band brake for my cube, similar to the one used in the &quot;M-Blocks&quot; [1]. Based on this video and the associated research paper, I&#x27;m quite optimistic about this kind of brake.[1] <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=hI5UDKaWJOo" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=hI5UDKaWJOo</a>.

Nice.That stainless steel work is very nice. I didn&#x27;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.

What if to keep it standing for the whole day?

Reminded me of the red cube in NYC <a href="https:&#x2F;&#x2F;publicdelivery.org&#x2F;isamu-noguchi-red-cube&#x2F;" rel="nofollow">https:&#x2F;&#x2F;publicdelivery.org&#x2F;isamu-noguchi-red-cube&#x2F;</a>

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: <a href="https:&#x2F;&#x2F;ethz.ch&#x2F;content&#x2F;dam&#x2F;ethz&#x2F;special-interest&#x2F;mavt&#x2F;dynamic-systems-n-control&#x2F;idsc-dam&#x2F;Research_DAndrea&#x2F;Cubli&#x2F;RevisedManuscript.pdf" rel="nofollow">https:&#x2F;&#x2F;ethz.ch&#x2F;content&#x2F;dam&#x2F;ethz&#x2F;special-interest&#x2F;mavt&#x2F;dynam...</a>

This is really cool. Would love to see a basic analysis of the physics - I know it&#x27;s just basic angular momentum and torque. Are reaction wheels somehow intuitive and don&#x27;t require you to think about these things?

You have to make fundraising to produce it on <a href="https:&#x2F;&#x2F;www.kickstarter.com" rel="nofollow">https:&#x2F;&#x2F;www.kickstarter.com</a>

Now put some of those reaction wheels in one of these, to give them lateral self balancing <a href="https:&#x2F;&#x2F;alienrides.com&#x2F;collections&#x2F;electric-unicycles" rel="nofollow">https:&#x2F;&#x2F;alienrides.com&#x2F;collections&#x2F;electric-unicycles</a>

It deserves to be said fully spelled out: this guy is one hell of a crazy motherfucker. Respect.

Just subscribed to your YouTube channel, hope to see more Mechanical Marvels from you! It&#x27;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.

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.

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.)

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.

Really Interesting! I had never seen it before.I would suggest v2 have photovoltaic panels on all sides so it could run indefinitely on a sunlit windowsill...

Damn, I have been living a lie. Now I won&#x27;t be able to sleep until I can build one for myself.

6000rpm cannot be silent, it causes the air to move and it&#x27;s perceived as noise.

This looks excellent. How could someone make this more silent though?How does one quieten fan sounds?

It would be cool if a gigantic one of this were made.People would love to see this in a museum.

I’m looking for more companies like these:<a href="https:&#x2F;&#x2F;www.evilmadscientist.com&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.evilmadscientist.com&#x2F;</a><a href="https:&#x2F;&#x2F;teenage.engineering&#x2F;" rel="nofollow">https:&#x2F;&#x2F;teenage.engineering&#x2F;</a>

Very cool project. I&#x27;m curious, was the bulk of that £2500 cost tied up in any one part of the build? I&#x27;m suspecting the CNC work.

Put this in a sealed wooden box and you&#x27;d have the basis for a magic routine that would fool many people. Especially when the box and what it&#x27;s standing on can be inspected. When the motors aren&#x27;t spinning, if this were enclosed, it would feel normal.

The title undersells it. It balances itself on a corner, can be knocked about and rotates itself to. And can balance on an edge.

Yeah it says it was inspired by the Cubli

I remember seeing this exact thing a couple years ago. Or is my brain bugging out? very cool nonetheless.

Should make the frame out of wood or some soft material so no one thinks you welded it to the table.

Gyros were also used to balance a massive passenger monorail in 1962 without a Raspberry-pi <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Gyro_monorail" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Gyro_monorail</a>

I would say cost, imagine the R&amp;D of the part itselft, but the cost of it in maintenance to the final user. I believe citroen had electromagnetic shocks in the 90&#x27;s and it didn&#x27;t catch much momentum but if you see the videos of it working, its exactly like you said, smooth as heck drive throwgh bumps.

I wonder why cars and trains don’t use tech like this to keep passengers stable, even when the road&#x2F;track has bumps. Something like this, built into shock absorbers, could be revolutionary for transport.

Ha, this project does seem extremely Dutch! Whimsical yet practical(ish).

very cool. reminds me of the alamo sculpture in astor place in front of the site of the old cooper union engineering building.

Cover the sides in something soft? Also it might be possible to control the fall so that the reaction wheel spins up just before estimated impact.

You know, once you implement the braking system, it seems like you could make it walk across your desk, corner over corner. Might be hell on the wood surface though.

If you showed this to someone in the stone age they would literally think you were a god and probably worship the cube.

I have been obsessed with this balancing cube for years now

I have been obsessed with this balancing cube forever now

The second I clicked on the video I instantly recognized those synths as being Kevin Macleod&#x27;s music. Very iconic

i mean this sort of thing usually gets like &gt;1k votes so thats an easy enough filter?

Would love if HN had a section like &#x27;show hn&#x27; specifically for long-form, lone-hacker, impressive stuff like this. Not sure exactly what the metrics would be that qualify an article to belong there but every few months I see something like this that has that &#x27;wow&#x27; factor, and wish there was an easy way to collect all of them.

I designed a cube that balances itself on a corner