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Show HN: I spent a year making an electro-mechanical prototype of a liquid clock (hellorhei.com)
681 points by damjanstankovic on Sept 26, 2015 | hide | past | web | favorite | 103 comments

If you liked this, you'll probably also like Ferrolic: http://www.ferrolic.com/

Super mesmerizing to watch the ferro fluid making its way through the display.

Edit: I remember reading that the ferro fluid used in Ferrolic would begin to lose its magnetic properties a few months in -

Ferrofluids are fundamentally unstable. They're colloidal suspensions that rely on surfactants to keep the particles apart, and as the surfactants degrade, the particles start clumping together and falling out of suspension. - jpatokal [1]

Is the Rhei somehow designed to last longer? If so I would be really interested in purchasing one if you ever decide to get them into production.

[1] https://news.ycombinator.com/item?id=10053251

If i use the regular ferrofluid it can last for quite long, however i dont like the effect of the fluid in that case, it has spikes and doesnt really look like a blob that i wanted to achieve. I have samples that are year old and work just fine so far.

Higher viscosity filler fluid and/or a ferro-binding compound to dampen the "springy" vibrations and ferro "spikes"?

Btw: Comes off a labor of love and insanely-awesome attention to design and detail. Outstanding. Kickstarter/indiegogo/lockitron selfstarter page yet? :)

Yeah making just any prototype should have been much easier, i really tried to make something that looks beautiful even when its not animated.

KS, maybe one day :)

Dude! You did already all that hard work; make some $$, gain more freedom, while it's hot.

If the cost of making another example (parts, time, skill) can be made sufficiently below (say 30-50%) of a reasonable sale price, it may be business. The real "hacking" done by contract manufacturers is cutting corners to make something beautiful, functional and inexpensive to manufacture.

Challenge, should you choose to accept it, if not already:

Try to assemble a similar example with mostly scrap, for the least budget imaginable. (Penny wise & pound wise.)

Another possible path:

Patenting and licensing to boutique clock makers / electronics firms, which frees you from nearly all the headaches of dealing with advertising, manufacturing and distribution (after negotiations, assuming one would usually seek advice/assistance of trustworthy, relevant partners). Also, people may not like patents, but it's a double-edge sword necessary to create a survivable business... without that, the newbie wantrepreneur is often shoot themselves, in not just one foot, but reloads to see if that stops the fail. It's nice to broadly claim "patents are evil," but good luck making money sustainably in an environment where anything & everything is knocked off, without recourse (usually legal) of any measurable kind.

Dude! Do you really think that KS is a quick and easy pile of cash, or let alone has anything to do with freedom? Have you talked to anyone who got funded that way, or maybe read a postmortem on a failed hardware campaign?

Idea: Ferrolic showing Rorschach faces until it's 'asked' to show time.

> Ferrofluids are fundamentally unstable

But not if you are constantly stirring them up. The Ferrorfluid used in loudspeakers for instance doesn't seem to degrade.

Awesome. :)

The slogan is geat too, I would just drop the "literally" at the end, I think it's unneeded. "Time flows" is perfect IMHO.

Can you explain how did the idea grows in your mind?

seems that HN won't allow him post more so he messaged me the answer:

--- yeah its funny, the first time i tried to make this was long time ago, here is the video 3 years old: https://vimeo.com/42313987

The idea was pretty spontaneous. I saw CZferro toys online and wanted to play with it so much. I ordered one and played with it and after a while i was thinking why couldnt this be something concrete. I loved the idea of translating something thats abstract in a visual sense to a concrete thing and back.

After that a clock came as a logical object, since it changes non stop.

So you contreted your idea by concreting time as an object without a solid susbstance. I guess you got it right. :)

Thank you for the explanation. ;)

Supposedly he felt like he needs to build something with ferrofluid the first time he saw that. There is a video of his first experiment somewhere, where the liquid was way less good looking but he managed to "fix" it over time and actually build the clock

Thanks for your relaying of the info. ;)

Beautiful object!

What was an unexpected problem you had? And how do you solve it?

There's a bunch of mechanical stuff going on. How much training did you have in that before you started?

What one thing will you remember for your next project?

Hi DanBc,

Thanks a lot!

Wow... were to start.. Perhaps the biggest problem i had was preventing the ferrofluid to stain glass and aluminum frame i used for the screen. I tried to get some help on the faculty of chemistry here in Belgrade, but no real success. Finally after months and months of experimenting with different liquids, you start to feel and "undertand" the way ferrofluid behaves.. very strange :) Its still not perfect but im working on perfecting it.

The first time i sketched the project seemed very easy, i will make a matrix of electromagnets and simply attract the ferrofluid. It actually gave some results but i realized that having a system that requires a huge amount of electricity to be spent all the time to simply show a number thats fixed - is not elegant. Here is one of the videos i recorded: https://www.youtube.com/watch?v=Kvp7bWe-M94

So finally i decided to go with neodymium magnets and mechanics. Building this from scratch was a crazy adventure of lots of lathe machining and cnc machining and so on.

I had no training basically i had to learn all along the way. I used illustrator for the most of the construction, since i am UI/UX designer, and finally gave it up and learned solidworks so i can make a whole 3d model of the clock and assemble all parts in 3D.

For the next project i think i will have to curb the need to make it "perfect", i lost A LOT of time beacuse of this. For example each time i wanted to make a screen for this i had to buy a glass, cut it on waterjet, then drill a hole, then glue to the frame that needed to be cut on waterjet also and polished before adding adhesive and so on. And once it does not work, i have to do it all again...

It's interesting to see that you're physically moving the magnets towards and away from the ferrofluid. Did you investigate electrically switchable permanent magnets?

e.g.: http://www.eclipsemagnetics.com/media/wysiwyg/datasheets/lif...

I know very little about them, other than that they're cool. The ones in that datasheet start about at about 2kg, so I don't know if you can get them small enough for your purposes.

yeah the size is the problem definitely. I experimented a lot with electromagnets and finally gave up, any result i could get didnt leave me with this kind of animation:


> I had no training basically i had to learn all along the way.

This is amazing. Very inspirational.

Thank you, much appreciated. I think this is my favorite project so far just because i learned the most.

#usraćuse :)


META - are you thinking about hiring the OP? These look exactly like some of my favorite questions when I interview candidates :D

Not to dismiss the website, but I could not reach it the first couple times so here is a direct link to the video: https://vimeo.com/140469553

I had a problem with my hosting, however one of my friends solved it. Thanks so much for jumping in :)

Does vimeo have some sort of unspoken rule that all videos must have a hundred cuts a minute or something? This style of film making is incredibly obnoxious.

It's shown to increase excitement and therefore engagement.

It is also shown to decrease the information density (w.r.t. the actual subject matter) of a video. So you have engaged viewers watching a video of less substance... Reevaluate what you are optimizing for.

And here I am, waiting for the video to fully load in another tab so I can skip around to find where it actually shows the product.

It doesn't seem to say so anywhere on the page, but "Rhei" is presumably a reference to the ancient Greek phrase, "panta rhei" (πάντα ῥεῖ), which means "everything flows." It's associated with the pre-Socratic philosopher Heraclitus, and while the phrase itself doesn't occur in any of his extant writings, it's reminiscent of his famous observation that you can never step into the same river twice.

Pretty awesome name for a liquid clock.

Rhei is just Greek (modern and ancient) for "it flows" (ρέει).

Which also gives us rheology (study of flow), diarrhea ("a flowing through"), rhythm (measured flow), etc. Ultimately coming a Proto-Indo-European root (*sreu-? I think), which also gives us the Rhine river and the word 'stream', amongst others. The more you know.

That is absolutely beautiful. Congratulations on creating such a unique object; you must be very proud of your work!

Thank you so much. I am really, considering the fact that i started almost 4 years ago, then paused after few months and then spent almost the whole last year on it. Thanks again!

author here, i will be glad to answer any questions you guys have

I couldn't find anywhere in the video where it was changing the time in real time....it either shows it while staying at a certain time, or shows it in fast motion. Am I looking in the wrong place?

I was also desperate to see this. And rightly so, here's what looks like a prototype link from above - and it's beautiful!


You can really appreciate the difference between the gentle movement induced with mechanically actuated magnets, and the nasty instantaneous movement which would happen with electro.

Yeah it was the biggest challenge, how to gently move liquid and not "expose" the mechanism behind it so it looks that liquid is moving on its own. I have a lot more videos, feel free to send me an email stankovicdamjan@gmail.com i will share. My plan is to publish the making of presentation by the end of this week

Does your clock require frequent refilling?

Hi Henk,

At the moment its working but its not perfect. The biggest challenge i had was to make this really look like fluid and kill the ferrofluid spikes. I simply wanted to animate the fluid not make it obvious that its a ferrofluid. So i had to thin the ferrofluid with all kinds of different things, some work better some work worse, still testing.

That's true! It's not viscous at all, which makes it all the more mesmerizing.

I was wondering about the spikes. What did you do that worked / didn't work to fix that?

What is the 'thickness'? I'm guessing only several millimeters??

actually this was the hardest part, how to make numbers look thick and REAL, and connected. Here is a GIF that shows this nicely:


Thats the reason why i had to work with ferrofluid and change its structure and composition, i wanted to have thicker numbers. Whole screen is 10mm thick inside, and numbers sometimes go up to 8mm of thickness. They are especially nice from the angle because the seem like they float and not simply stuck to the wall. I will make better photos definitely.

You've done that quite well. I'm surprised its that thick, but it looks like it give the numbers an awesome rounded look.

Really adds to the organic look and feel.

Well done!

Yeah, when there is no number it turns to big blobs of liquid that actually touch walls of the screen on both sides, so i guess its bigger than 10mm in that case

How long did the process of making the video take? Since this is mostly an art project, was filming done gradually over the year along with R&D, or only after the clock was finished?

Was this funded by a grant, or is it a personal investment in hopes of selling completed versions of the clock?

Hi Vortico,

Shooting took around 7 days because we were on a very tight schedule, trying to make it for the public announcement of the red dot results http://www.red-dot.sg/en/online-exhibition/rhei/

The good news is that i do have all the process over the year documented, if you want i can upload some photos but i am writing a making of presentation that i will place on behance and medium. I think it will be a really useful story for an industrial design student or someone who has good ideas but still not sure if he should start prototyping or not.

This was funded solely by me, which made it so much harder. I had to do freelance by day and work on this by night. Its difficult especially because prototyping means you have to make the same thing many times over and over again and its really time and money consuming.

Is that Adagio in D minor in the video? Who made this version?

Guys that made video know what the song is, its a bought from audiojungle. I will find out whats the name or url

Absolutely fantastic idea and execution. Props to the video producer(s) as well.

One question: what sort of power consumption is required to maintain the digit positions inside of the enclosure?

I'm guessing none. Looks like a servo is moved, which moves permanent magnets closet or farther from the fluid. Once the servo moves the magnets to the desired position, no further power would be required. So looks like just a burst of power every minute to move the servos and nothing more.

It could get away with none, however i wanted it to constantly move even while numbers are changed - otherwise i asked myself why build it out of liquid if its not moving.

On the other hand, you are right, it only draws power when it moves and it moves every other segment every few seconds which is enough to constantly animate the numbers, because the fluid needs time to readjust.

The motors are actually stepper motors, which made it all harder, because its not as easy to move them as it is to move servos, and steppers have no idea where they are which required an initial calibration sequence. The good news is that steppers are not loosing any steps, i guess the mechanics work very well.

Is the display fast enough to include seconds?

It could, currently for animation i use 5 second interval, because its much more nice to look at because liquid slowly transforms. I will include new videos an GIF to show this.

However seconds would be doable but it would result in animation being constant since it needs about a second to transform, so i finally decided to go with HH:MM

Here is another video of this little thingy: https://www.youtube.com/watch?v=SoOMQ8TaTyE

you can see that the liquid is quite different, it was long time ago, but it basically acts the same but looks more blobby

Some of you asked for a video of nubmer changing. Here it is completely behind the scenes with visible mechanics, enjoy:


Hey guys,

Damjan asked me to post a comment here, he says he is sorry but HN is not allowing him to respond to all coments quick enough. But stay assured he will anwer each and every question. :)


THIS is inventing a clock

You know, not every situation calls for belittling the achievements of children in the news.

What achievement? Buying a clock from the 70s and putting it in a suit case to bring to school?

From my understanding of American culture derived from a thorough reading of Peanuts, I thought you were supposed to bring hastily assembled items to school. You wouldn't dare say something like that to Sally Brown about her leaf collection.

Anyone know what the music is here? Shazam seems to be giving me false results :(

Its a stock music from audiojungle :)

I want these as individual 7 segment displays. Or 16 segment.

Just FYI I interpreted the URL as "Hell or Hei" which might not be the impression you want to give.

I assumed that was intentional- "come hell or high water", liquid clock, it makes a lot of sense in a punny sort of way.

yeah my bad, i forgot to put a capital R which helps a lot in this case :)

Great man, I would like to purchase this clock! Please sell me that prototype :D

umm.. that would be very expensive :))

Any ballpark figures you'd like to release?

Really nicely done!

Is all the equipment yours or did you work in a Makerspace or something?

Check out the credits at the end of the page: http://www.hellorhei.com/

No mention of a particular Makerspace, but obviously a lot of collaboration with people with various tools/skills.

Yeah, so far no makerspace here in Serbia, however we have a lot of small local businesses and craftmans that you can pay to get something done.

How can i buy one of these? And how much does/would it cost? :)

At the moment its only a prototype. After some testing, if it reutrns promising results i would be more than glad to produce a smaller quantity of these. Unfortunately i have no idea about the price, sorry.

A DIY kit would be great - I would pay for just the parts and instructions.

Magnets & ferro fluids, excellent.

Because of the video, I can literally see through the box into the 7 segment magnet chunks moving with the servos when the time ticks over. I like the simplicity & the way the tick flows into shapes.

@damjanstankovic: can you throw up a Cinegraph/GIFV below the fold or something, so that the flow is clearly visible before we even head into the video itself?

Like a 1,2,3...9 sequence for the last digit, because the beauty of that should hit the next person who clicks this.

I am just working on this :) Somehow we missed to put a part of the transforming numbers in the video because we were on such a tight schedule. I will be updating website and more important i will launch the making of document of the whole project that will show all of this.

GIF on the way :) thanks a lot!

This reminded me a lot of the "world of goo" you should check it out I'd you haven't. It's an indie game. (PC originally but later ported to phones)

I found it on youtube too! http://youtube.com/watch?v=p5b_m6ucpAQ

I love this sort of build video. I wish I could watch for hours the setting up of the various machines and the construction of the different parts.

The project itself is amazing, but this is also one of the most beautiful websites and captivating videos I have seen in awhile.

Vide is a product of two very talented guys, Djordje Stojiljkovic and Nenad Veljovic. I will pass on your compliments to them. As for the website, that would be my primary profession UX/UI design :) Althugh it was all done in 1 day.

You guys did a good job!! Amazing.

This somehow reminds of iOS game Feed Me Oil. https://www.youtube.com/watch?v=X6qhbZkMA0Q


Most of the innovation in consumer clocks is aesthetic. Anyone can pick up a clock from Walmart that does everything they need and will last for years for cheap. Displaying the numbers by manipulating magnetic fluid is an interesting and pleasing way to do things. It's never going to be cheaper, more reliable, or more efficient than and LCD display. However, it doesn't have to be. That's not the point.

This definitely the clock that would sit on Rorschach's desk.

Really loved the project. Would love to get one of these if you ever make this available to purchase.

Call the cops he has a clock!!! j/k... What a wonderfull piece of engineered art.

Thank you, the making of presentation coming soon!

Damn! Time to scratch this idea off my list. GJ

This is a great project. As someone has mentioned, check out http://www.ferrolic.com/

Also a great project but I like the design and the fluid itself better with Rhei

Simply amazing.

Very impressive.. I'd buy one too.

Congragulations... It's great :)

Just don't bring it to school!

He didn't shuck a Micronta clock and hot glue it into a pencil case.

Why does the press kit make me download a zip? I just wanted to learn more. Cool idea though.

It was mostly for newspaper websites so they can get photos when they are publishing stories. Thanks!

Flash = not viewable here. Why not put this on YouTube instead of Vimeo?

I don't think it's a flash issue (unless it's something else with the parent site). I was just able to watch the video on vimeo in linux+firefox, and I do not have flash installed.

Vimeo's player does indeed default to HTML5 video [1].

[1]: https://vimeo.com/player

Yeah, it doesn't work for me either.

there's a youtube link up there

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