Digital Sundial

by Mojoptix, published

Digital Sundial by Mojoptix Oct 13, 2015

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Digital Sundial by Mojoptix is licensed under the Creative Commons - Attribution license.

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The episode in [ENGLISH]: http://www.mojoptix.com/2015/10/25/mojoptix-001-digital-sundial/

L'épisode en [FRANCAIS]: http://www.mojoptix.com/fr/2015/10/12/ep-001-cadran-solaire-numerique



For those who have trouble slicing the gnomon, I ran the files through netfabb and re-uploaded them as:
-- Gnomon_Southern_NETFABBED.stl
-- Gnomon_Northen_NETFABBED.stl
Let me know in the comments if they don't still behave nicely with your slicer.

If you wish to print the gnomon in two halves :
-- Gnomon_Northen_half_1_of_2.STL
-- Gnomon_Northen_half_1_of_2.STL
They should fit on a 100x100 platform. (Thanks Zarlor for building these two files and fixing them ! )


Tadam !
A Sundial displaying the time inside its shadow, with actual digits ! There is a tiny bit of magic inside...

No batteries, no motor, no electronics... It's all just a really super-fancy shadow show. The shape of the sundial has been mathematically designed to only let through the right sunrays at the right time/angle. This allows to display the actual time with sunlit digits inside the sundial's shadow.

The sundial displays time (with actual digits !!) from 10:00 until 16:00, updating every 20 minutes.
You can precisely adjust the displayed time simply by rotating the gnomon (the magic box that displays time). So you can even adjust for Daylight Saving Time.

You'll also need :
--- an (empty !) jam jar
--- 3x M6 screws, flat head, length = 20 mm
--- 1x M6 screw, flat head, length = 50 mm
--- 4x M6 nuts
--- 4x M6 washer, outside diameter < 14mm

Tadam !
Un cadran solaire qui affiche l'heure dans son ombre avec des vrais chiffres ! C'est un peu magique.

Sans piles, sans moteur, sans électronique, etc... Il s'agit juste d'ombres chinoises très compliquées. La forme du cadran solaire a mathématiquement conçue pour laisser passer uniquement les bons rayons du soleil au bon moment/angle. Cela permet d'afficher l'heure en chiffres lumineux à l’intérieur de l'ombre du cadran solaire.

Le cadran solaire affiche l'heure (avec des vrais chiffres !!) de 10:00 a 16:00 toutes les 20 minutes.
On peut ajuster l'heure en tournant le gnomon (la boite magique qui affiche l'heure) sur lui même, par exemple pour passer de l'heure d'été à l'heure d'hivers.

Vous aurez aussi besoin de :
--- un pot de confiture (vide !)
--- 3x vis de taille M6, a tete plate, longueur = 20 mm
--- 1x vis de taille M6, a tete plate, longueur = 50 mm
--- 4x boulon de taille M6
--- 4x rondelles de taille M6 diametre exterieur < 14mm

Timelapse: https://www.youtube.com/watch?v=EoGVb82uCnA

Print Settings










Use ABS !!!!
It is something you'll want to leave under the sun, outside: PLA will deform under the sun heat. And some PLA biodegrade faster than others when left outside.
The inside of the gnomon is a fairly complex switch cheese. You should aim to print the gnomon with 0.1 mm layers or thinner. Otherwise it will most likely have some errors in the digits displayed.
The other parts can be printed with thicker layers.
Note: Print only the gnomon corresponding to your hemisphere: Northen / Southern.

Utiliser de l'ABS !!!
C'est quelque chose que vous allez laisser dehors, au soleil: des pieces en PLA vont se deformer sous la chaleur du soleil. De plus certains PLA sont plus rapidement biodégradables que d'autres...
L’intérieur du gnomon est un gruyère carrément compliqué. Essayez d'imprimez le gnomon avec des couches de 0.1mm ou mieux. Sinon les chiffres ne s'afficheront pas toujours correctement.
Les autres pièces peuvent être imprimées avec des couches plus épaisses.
Note: n'imprimez que le gnomon correspondant a votre hemisphere ('Northen' pour hémisphère nord, et 'Southern' pour l'hémisphère sud).


Don't forget to remove the breakable support material on the 'bottom part' (the two thin half cylinder inside).
To get the brighest display, try to set the angle between the ground and the gnomon equal to:
-- in spring and summer: your latitude - 10°
-- in fall and winter: your latitude + 10°
You can fine tune the time displayed by rotation the gnomon around the top-most screw, for example to adjust for Daylight Saving Time.

N'oubliez pas d'enlever la structure de support sur la pièce 'bottom part' (le couvercle): il faut casser les deux (très fins) demi-cylindres a l’intérieur de la pièce.
Pour un affichage optimal, inclinez le gnomon tel que l'angle entre le sol et le gnomon soit égal à:
-- printemps et été: latitude - 10°
-- automne et hivers: latitude + 10°
Vous pouvez ajuster précisément l'heure en faire tourner le gnomon sur lui-même, par exemple pour passer de l'heure d'été a l'heure d'hivers.

How I Designed This

The episode #001 of the video podcast Mojoptix describes the invention of this sundial in details:

L'épisode #001 du podcast video Mojoptix décrit l'invention de ce cadran solaire en détails:

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My mind just exploded

How are the two parts of the Northern STL's connected?do I have to modify the model to combine the two part to one after printing?

Maker Geeks box sent me here. Thanks!

thanks to who?

can this be printed at half scale

Does it work on 82% scale? because my Printer is only 10x10x10

10 inches x 10 inches?

the southern half 1 of 2 and 2 of 2 don't have the connectors that the northern half 1 of 2 and 2 of 2 have. is there a reason for this? and could they be added on please?

can you create it with fdm printer ?

Idk try it out

Im thinking about selling these at a craft fair. As far as I can tell the creative commons does allow that as long as i include the credit page with the sell. Do you feel otherwise?

I set mine up during today's partial solar eclipse --- that was awesome! Pictures in the "I Made One".

Want to try printing this brilliant design, BUT I am a bit confused about settings and don't wish to experiment since it is a ~25h print...
To my best understanding the suggested settings are:
Temperature & speed: on the low edge to improve bridging
Layer height: 0.1mm
Raft, to improve 1st layer
Infill 20%
Line width ??? I am using a 0.4 nozzle. Do I have to go manually down to 0.3 or 0.2 or what ???
Any other suggestions?
Please base your answers on your experience printing it.

The concept is brilliant, but the Video explanation takes it to another level, Exceptional.
Thank You

I just fixed my printer and I am going to make this next been dying to make it really good design.

So, how did you actually make this...? Looks quite complicated...

I'm facing troubles printing this sundial. It fails when it comes to the details. The little bridges don't build as thes should. The filament falls down in between leaving to ends pointing at each other from each side but don't touching. With luck the next layer builds up on this parts.

Did someone face the same troubles? What can I do?

I tries printing 0.2 layer height with a 0.4 nozzle.

Comments deleted.

Will it work in the Southern Hemisphere?

There is a Southern version included. So yes. ...or just try holding the Northern one upside down (just kidding).

Did anybody print this in Vertical position? My Printbed is too small but if i flip it 90 degrees in vertical position it is no problem for my Kossel mini, but i guess it won't work without support and if you print this with support you will probably never get rid of it..

Or did it anybody succesfully?

Has anyone tried this in Sweden? Ditt ringer and summer time? Since the winter is the real time ( I Think)

Det borde gå fint. Man måste ställa den ändå när man sätter upp den. En timme är en timme. :-)

You should submit this to education.

you didnt gave any credit whatsoever your amazon page even says its by you, the license clearly states that you must give credit

actually you dont seem to give any credit for anything you sell, kind of unfair to the original creators

Awesome work. Cant wait to try it out. Anyone know if it will still work if it is scaled up?

A really nice thing. It has Printed works right !

how long did it take to print?

12 hours and change with .10 res. and 20% infill. print base and connector at lower res. and save the time high res. for the dial.

Komplett 20 Stunden

For the non-German speakers out there, that means "completed in 20 hours".

(To be fair, that's only for English speakers. Other languages: 20 heures / horas / ώρες, часов, jam, 時間, hores, ਘੰਟੇ, ora, گھنٹے, ساعات, 시간, and 小時. (I think that covers a good chunk of the world's population - if you count L1/L2 speakers, well over half (!) - so if you're offended at being left out, I apologize. (And you understand English enough to claim to be offended, so, no. >;-) And if you think I left out Hausa - that's "hours" as well, for another 41 million people... >;-)

Nice but i gonna remix it to print it faster and save some filament. Before finishing a design you need to add holes on some parts.

I'm speechless....This is WAY too cool! Excellent work!! :D

This is absolutly amazing!

So cool! How did you make that work? It's amazing!

The instructions say "supports : NO" has anyone achieved this with no support structure?

I'm currently printing half 2 of 2 right now. The first half came out amazing with no supports. I printed at .1 and super slow (15 for walls, 30 for infills). Took a solid day but it's a very crisp finish and all the swiss cheese inside is clean and in tact. Very slight stringing that's easy to clean up and don't harm the quality, but just retraction tweaks I need to fiddle with and that supports wouldn't have solved.

The instructions say "supports : NO" has anyone achieved this with no support structure?

What's the difference between the "NETFABBED" files and the same ones without this written?

What's the difference between the "NETFABBED" files and the same ones without this written?

Read what he wrote. Some slicers like Reptier might show it as open mesh and NETFAB fixed it.

Super cool. I have 2 versions printing now, one on the FDM and a scaled down one in the FormZ at super high resolution.

Would it be possible to get this as a 3D solid model (STP, IGES etc) so I can play with it in Solidworks.....I am contemplating making a giant one out of aluminum, hence the desire for a solid model.

Thanks and love it.


Super cool. I have 2 versions printing now, one on the FDM and a scaled down one in the FormZ at super high resolution.

Would it be possible to get this as a 3D solid model (STP, IGES etc) so I can play with it in Solidworks.....I am contemplating making a giant one out of aluminum, hence the desire for a solid model.

Thanks and love it.


Super cool. I have 2 versions printing now, one on the FDM and a scaled down one in the FormZ at super high resolution.

Would it be possible to get this as a 3D solid model (STP, IGES etc) so I can play with it in Solidworks.....I am contemplating making a giant one out of aluminum, hence the desire for a solid model.

Thanks and love it.


Super cool. I have 2 versions printing now, one on the FDM and a scaled down one in the FormZ at super high resolution.

Would it be possible to get this as a 3D solid model (STP, IGES etc) so I can play with it in Solidworks.....I am contemplating making a giant one out of aluminum, hence the desire for a solid model.

Thanks and love it.


Super cool. I have 2 versions printing now, one on the FDM and a scaled down one in the FormZ at super high resolution.

Would it be possible to get this as a 3D solid model (STP, IGES etc) so I can play with it in Solidworks.....I am contemplating making a giant one out of aluminum, hence the desire for a solid model.

Thanks and love it.


Comments deleted.

will a resign printer (formlabs) work or be okay? it cures in UV light.....

Looking forward to making this with my kids. Great way to show them ancient and very new technology at the same time. Thank you! (This via http://www.sciencealert.com/it-took-thousands-of-years-but-we-finally-have-a-digital-sundial?perpetual=yes&limitstart=1 is what brought me to Thingiverse for the first time.)

Looking forward to making this with my kids. Great way to show them ancient and very new technology at the same time. Thank you! (This via http://www.sciencealert.com/it-took-thousands-of-years-but-we-finally-have-a-digital-sundial?perpetual=yes&limitstart=1 is what brought me to Thingiverse for the first time.)

Looking forward to making this with my kids. Great way to show them ancient and very new technology at the same time. Thank you! (This via http://www.sciencealert.com/it-took-thousands-of-years-but-we-finally-have-a-digital-sundial?perpetual=yes&limitstart=1 is what brought me to Thingiverse for the first time.)

Two questions:

Should I use a dark color for the filament, or would glow-in-the-dark filament work just fine to create the shadow needed?

Also how much ABS filament was needed for this?

Many thanks!

does this tell minutes?

The video demonstrates that it only shows the time in increments of 20 minutes. For example, it would display 10:00, 10:20, & 10:40 over the course of an hour. Hope that helps!

Is it safe to scale this print? It's just slightly bigger than my bed.

I think scaling to 80% makes it fit.

I scaled to about 80% on Ekocycle, and the third digit was too cramped. If I recall correctly, you can print the left and right sides separately, which I recommend doing.

That said, my printer prints at ~70 microns, so it might work just fine on yours.

Printing now on TAZ 6 with MatterHackers 3mm Pro ABS filament. I'm wondering if anyone has tried acetone vapor smoothing on this without destroying the print??? Some of the features are so tiny, it seems even quick exposure to acetone vapor could ruin the functionality.

Great idea! And I love Margu's modifications to ease transitions.

However, I'm a typesetter and the spacing used between the digits and between the colon ad the digits makes my teeth hurt,

I loaded downloaded OpenScad for the first time today, and after an hour or so I figured most of the project out.

The problem is, what lines change the spacing between the various blocks? I tried reducing "gnomon_thickness" but that left gaps between the various blocks.

Can anyone provide insight?

Also, the wall divisions between the columns needs to be a tiny bit wider, how would I do that?

Extrusion width = 0.2mm. And 0.1mm layer height.

Id love to print this as one piece but appears that JAVA is causing problems. Slic3r and replicatorg keeps crashing constantly.
Thank you for sharing this is AWESOME!!

who ever designed this is a mad man!

Such a cool Idea! Thank you, for posting this, I was very pleased with the print, Now if only I could find the right size jar to mount it to, but that's a minor problem. again Thank you for posting!

How do i know what i need?

-- Gnomon_Southern
-- Gnomon_Northen


It is the hemisphere that you are in. (Most of) Europe, Asia and North America are northern, (most of) South America and Africa are southern.

Are u from ecuador?

Comments deleted.

What about.. do you live on the NORTHEN or SOUTHERN hemisphere ?

If i will resize it for 3mm - It can destroy the model?

Anyone, what was your layer height and print speed for this?

I've got Cura set to .1 with a 1.05mm wall, 3 walls, (default for selecting "Normal" quality in Cura 2.1 beta), 20% infill, 45mm overall speed and I'm looking at 28.5 hours.

I've got an Ultimaker 2+, and I know it can print fast, but this model looks like there are some parts that need very precise printing and I think speeding it up might cause certain parts to print properly.

I've opted for .2 and I'm at 14.3 hours.. little more manageable.

If I print it in a 0.7 scale (30% smaller than the original model) It will work good too?

I simulated in software simplify3d and took about 804 minutes all the 4 pieces. Using 20% infill, medium quality. Is that correct?

yeah last print took me 12 hours. And the 16th layer covers all the holes up for about 7 layers. 12 hours gone. and alomost 1/2 a roll of fill.

Thats extremely clever

Do i have to print the sundial with or without supportmaterial

Alguien lo ha modificado, para el huso horario de México?

No hay nada que modificar. En los archivos que descargues encontraras una impresión para la gente que vive en el hemisferio norte y otro para la gente que vive en el hemisferio sur. Visita su página tiene un video en el que lo explica todo. Eso sí deberás saber inglés o francés. http://www.mojoptix.com/

A Tostitos brand salsa jar is a great fit for the lid here in the US. You have to give it a good hard turn but it'll fit.

Seems with both a .4mm and .5mm nozzle, both Cura and Simplify3d are not slicing some of the bars. Can this get scaled up, or are there any suggestions to fix that?

You need to go manual for extrusion width, and adjust down to 0.2mm. And 0.1mm layers height is recommended.

Got the same problem

Awesome!!! I take my hat off to you. Congratulations!! ;)

So nice ! Congratulations ! And you share the new century concept : open-engineering !!

I tried printing the 20 minute digit (the one that displays 0,2,4 and I tried Simplify3d and Cura and a lot of the obstructions are ignored by the slicers. When I print it the 2 never gets displayed because a few pixels stay lit.

.4mm nozzle and .1mm layer but even if I tell the slicer that I have a .1mm nozzle the obstructions get ignored

Any ideas on how to fix this?

Is it possible to shrink the model ?

Printing this project is how I learned that there exist metric jam jars. >:-(

Awesome job designing this!

Now, to hit the lathe to make my own damned weighted base.

what is the best printing position: vertical or horizontal?

What are y'all doing so that it doesn't take 30+ hours to print the dial piece?

Took me 12hours in s3d. Its a high detail piece and most printers and nozzles will just fill n the display holes

I made it and it is perfect!! But i cannot find this empty jam jar ,i don't find the right size. Can you figure out in in an .stl file so than print that jam jar to the right size please. Or at least what is the right height having print all printable parts?

Go to the grocery store and get yourself a small jar of Old El Paso Salsa (other brands work too) The jar opening is the perfect diameter. Grab some chips too,

WOW That is amazing. I have been trying to figure out how to do that. I am going to print it right now.

Good luck Im on day 3 now. I've wasted 1.5 spools of fil. and Ive watched 3 prints take over 12 hours and the dial never prints right.

I live in Chichester in the UK and my sister lives in Chicago in the USA. Is it just a case of rotating the actual sun dial to get the right time? I only need the northern for both places.

I feel like an idiot but where are the instructions on how to assemble this after printed? I have all the hardware and I just can't figure it out.

The top part attaches to the round lid by 2, 20 mm screws, (lid sides facing down as this will go on the jar) secure with washers and nuts.
The connector piece fits into the top piece by the extension piece (round side up) Use the 50 mm screw to pass through the side of the top piece and the connector. Again secure with a washer and nut.
Last part will be to attach the main sundial to the connector. This is a little tricky. Turn the assembly over and slip a 20 mm screw in on one side and a washer and nut on the other. I would put the screw on the connector side and the nut on the main sundial side. Getting it tight enough to hold may take a little dexterity with a needle nose pliers. Not too tight as there should be some ability to rotate the sundial piece slightly if needed.
This is how I am going to put it together,
Hope that helps.

Made it. Awesome. Takes a considerable amount of cleanup on the bottom to get that first layer off but it's worth it!

awesome idea but when I 3D printed it many of the fine filaments broke off or simply weren't there. I printed at 0.1mm res. I wonder what would happen if I scales it up?

I printed the two halves but the do not go together. What did I do wrong? I was using the Northern files.

Having the same problem... was expecting male/female assembly or flat surfaces...
Anyone can cut the simplified design into parts and make it available for us with delta printers and small bed?


Many thanks and bravo for a smart and innovative design!

Digital Sundial cleansed
by Margu
Comments deleted.

Great design, very clever !
You can actually see the digits if you hold it up to the light horizontally and look at it with your eyes almost closed.
Just rotate it in your hands to see the time change.

wow wow wowie! i never would have thought this was possible. that is perhaps the coolest thing i have seen here. i don't see how you were able to figure out where to position the holes for the sun itself to display a digital readout. makes me wonder a bit more about stonehenge. great job. i will be printing this later today, thanks for sharing! question can i sell some?

Look at the creative commons thing. Duh... You can sell it.

Absolutely fabulous and brillant !
Congratulation as well for the smart and fun video explaining the design on a wide perspective.
I and my sons have watched it with a lot of pleasure.
Can't wait to see what will come next in your podcast :-)

Mojoptix, This excited me enough to print one and show my friends. They think I'm a genius, but I tell them the genius is on Thingiverse.
I wondered why the figure 2 was not as clear as the other numerals. In your scad file, I think the fourth line for "2" could be 0,0,1,0 rather than 0,1,1,0. Just my preference maybe, and not meant as a nit pick.

Hello! I have uploaded my Customizable Digital Sundial. The same thing, but you can customize what you want to display, and a lot of other parameters. Take a look: http://www.thingiverse.com/thing:1253190 Enjoy!

Customizable shadow display

you rock epic one cant wait heating my printer up now

One feature of OpenSCAD is the projection command. One can translate the object in Z and "cast a shadow" in the workspace of that specific location. Export the SVG files. Consider that one can slice the STL in thickness of 3mm or 1/8" suitable for laser cutting from cardboard or foam. Glue the slices together, protect the exposed surfaces (big job for the little holes) and cover it with fiberglass. Result: Huge digital sundial suitable for one's courtyard.

Fantastic object! Remarkable piece of planning, brilliant

Wow... It's just AMAZING!

does this work if you shrink it down?

how do you know which angle from the sun to put it, once printed?

Angle it up or down until the numerals are clear. Angle left or right until the time matches the current time. (My guess based on logic)

[sarcasm]I bet it doesn't work at night...[/sarcasm]

Great job on designing and implementing this, seriously!

I bet it does if you use a torch (at the right angle of course) :-)

This is genius! I second the nomination for most ingenius design of 2015. Where do you go from here though? :-)

More Clarity (By removing unneeded intermediate segments making transitions sharper)
More Accuracy (By reversing the time direction moving the least significant digits to the bottom and increasing their size it could display smaller increments of time)
See this work in progress: http://www.thingiverse.com/thing:1149469

Digital Sundial cleansed
by Margu

The most ingenius design of 2015!!!

Has anyone had success on a Replicator 2? What were your settings?

Hi !
Amazing job.
I've print 2 half parts, but don"t know haw to connect them...
any help will be welcome :) Thanks in adbance

In French :
J'a imprimé en 2 partries, mais ne trouve pas comment les assembler.
Sui quelqu'un peut m'aider ,merci d'avance, et encore bravo pour ce génial objet.

The digital sundial is a brilliant design!

We mounted the halves on a sheet of clear acrylic plastic sheet (3mm thick) using some self tapping screws. That holds both halves in perfect alignment.

We printed ours in PLA on an XYZ Da Vinci JR printer with excellent results. Placing the two critical halves on the plastic sheet might help overcome and issues with distortion under hot sunlight.

One of the coolest things i have seen on here.

C'était très intéressant!

I actually speak primarily English, but really great job, such a great concept and execution.

Awesome design!

Is this still working if you scale it up and make a big one?

This is awesome, great work


English version below
Bravo bravo bravo.
Votre idée est très originale et très bien réalisée.
J'ai publié un remix optimisant les découpes. Je vais bien évidement poster le fichier OpenSCAD modifié dès que je l'aurais documenté le code.
Je n'ai rien imprimé car je souhaiterais en avoir un plus grand (pas compliqué à faire) mais surtout dont l'ombre sera sur un mur (vertical donc) et pour ça, j'ai besoin de votre aide

A suivre.

Bravo bravo bravo.
What an original idea. And well done.
I publish a optimising cuts. I willobviously post the modified OpenSCAD as soon as I I documented the code.
I didn't print it since I want to build a bigger (not complicated) but with the shadows projected on a (vertical) wall and for this, I need your help.

To be followed.

là, je suis 'achement impressioné !
Bravo !

Man, that's an awesome idea! Printed it, works great, although it needed a lot of tweaking after printing.
One clue for the next version: Many of that small bridges are not even needed. On the first digit, for example, i cut them all away. On the last digit, you already did. The other digits were too complex, so i'll better leave them as they are. But even with a print that stopped after ~8mm, almost all the second digit hour-numbers did already work!
If you write a code that adds material just around the pixels we need, instead of subtracting from a solid, maybe that might produce a less "cheesy" construction :-)
Thanks for sharing this one, anyway!

I made a remix cleansed.
The principle of my optimization : During digits transition, there is no need to block the light for pixels which remain lit.

Just have a look.


Really awesome to see people willing to dig into the Openscad script :)
Do you mind just adding a link to my website somewhere, maybe in the Readme file ?
It will make it easier for people wanting to ask me questions about parts of the code.

And some well deserved credit! Awesome work man. Thank you for sharing.

Definitely, done!

Wow man, what an idea! FRESH!!!!

I would like to endorse Tanato's comments, thanks for this, now to print!

Although I don't have any use for this device at the moment I just wanted to say thank you for sharing such a good stuff with the community! Good for you!

Comments deleted.

Great idea and excellent realization!
Unfortunately I tried for some days without success to print this great thing on my Flashforge Dreamer sliced with the bundeled Flashprint.
No chance to print into the air over 6mm. I tried it with ABS and PLA, with temperatures from 220°C to 240°C for ABS, layer thickness from 80µm to 150µm, print speeds from 20mm/s to 60mm/s.
The most bridges didn't reach the opposite border. It seems that the print head returns a little bit too early to glue the strand to the corner.
Has anyone had success to print this part on the Flashforge Dreamer and are there any hints to succeed these long airprints?
A g-file for the Flashforge would also be welcome.

This is a FANTASTIC model!!! It's super neat and functional.
I'm guessing you made it only show every 20 minutes due to the limitation of how small the tiny parts could be built on a 3D printer. I'm wondering if we separate out each digit into it's own printable piece, then we could enlarge the 10's digit (and MAYBE even make the 1's digit) then show every 10 minutes. We would just need to build a joint structure that would support the weight. Since the hours work fine, can we reverse the digits so that the hours are at the top and remain the same size and put the minutes at the bottom (Basically reverse the direction of the display so the heavier parts are at the bottom.) Let me know if that's something you might pursue, otherwise I may start digging through the SCAD code.

Am I the only one that noticed the Death Star plans on the wall in the episode? Yall gonna try to 3d print a fully operational space station? Now THAT would blow my mind! Aaaand maybe a planet or two but, eh... Although I was wondering if this did minutes and whether or not it was possible to do that and seconds with this design, although seconds would probably be really fun to print.


Je me demande si la pensée pour cette idée a eu quelconque ajout vegetal par ce que c'est assez des pensées paralleles..

Witch! Witch!

Seriously. Awesome. Work!

This is the best thing since sliced bread!..... I printed it last night, the place I had the most issues with was the minutes (first digit), It would be nice if a small "test" piece could be made out of it with the same bridge sizes etc so you could get your printer dialed in before printing. Also I printed the 2 halves, only because I didn't want to get 9 hours in and have my printer mess up and have to start over, would be nice if the model was broken further, digit 1, 2, 3, 4 so you could print each digit individually, this way you could repeat a print if you had to.

Anyways great job, My grandfather used to smelt aluminum, make sand molds and built sundials as a hobby, Can't wait to show him one of these!

This is brilliant!

thank you this is awesome

Several months ago I began reading about sundials with the idea of making a sundial based on the seven-segment digit code I wrote for my Illumination of Pi lamp (http://www.thingiverse.com/thing:903332), but I ran into some problems with my design and never completed it.

It's great to see this and that you've elegantly solved some of the problems I had encountered. Fabulous design!

The Illumination of Pi
by marciot

Putain-de-brillant. Je suis tout à la fois émerveillé et jaloux!

Vite la fin de la journée pour imprimer ça....


A really great thing!
I downloaded all files, but only the netfabbed file is loadable in ReplicatorG.
I printed it, and it seems to work fine (tested with a cree torch).
But even the connector.stl or toppart.stl are invisble in my version of ReplicatorG.

I ran these files through Netfab and uploaded them as ****_NETFABBED.stl
"Netfab" is my new favorite magical incantation.
Give these files a try and let me know if that improves things !

i'm very impressed.

I haven't download it yet, but just want to say that I had with this one a real WOW-feeling. Wat a great idea!
Thank you for this!

This is really brilliant. So well done and the video is amazing. Thanks for taking the time to explain both how sundials work in general and how yours works specifically in terms that anyone can understand.

To add to the short wish list, because very few things could make this idea any better, I'd love to see a 12 hour version in addition to this 24 hour version.

Thanks! Keep up the great work!


OK, I used this as a learning opportunity for myself and took a look at the code in OpenSCAD. I adjusted it to be a 12 hour clock. The code was written so nicely that it was no trouble at all. Thanks, @Mojoptix!

You can find the 12hr version here: http://www.thingiverse.com/thing:1112347

Digital Sundial 12hr Gnomon

That is such a really cool idea !!
nicely done !

this is fantastic! thank you for the tutorial as well!

This is very cool.
A lot of the really tiny little bridges don't seem to be necessary. I had a look at the code but not quite got to grips with it. Are they there for a reason or are they just irrelevant bits that happen to be left behind after all the cuts? I think a lot of them could be taken out to speed up the print and simplify the slicing.
So far I've only printed the 1st half of the gnomon but it came out fine at 0.3mm layers and was no trouble in Slic3r.
Great idea elegantly implemented.

i can't slice it in Cura, slic3r or something else.
Can anyone rapair the south gnomon file for me?

Thank you in advanced

Aloha !
I just ran the file through Netfabb and uploaded it as Gnomon_Southern_NETFABBED.stl
Can you try it out and let me know if you can slice it ?

Thanks so much, now i can slice it.
Great support.

Incredible, old and modern technology all in one

Super! Also a very nice tutorial on how you designed it (including cartoon background)!!

What! Blew my mind!

I'm gobsmacked. My gob is just gone.

GOOD IDEAL! If you can put a magnet to your product base to make it auto rotate to found the direction then it will be perfect.

Doesn't seem to like Slic3r without having to be repaired first.

Completely brilliant!! :D

You my friend have given me a reason to fix my printer!

Congratulations on getting featured! No problem slicing in Mattercontrol with Matterslice.

this is by far the most creative thing on thingiverse i have ever seen!!!
perfecto! te felicito!!

This is a genius design!!

Holy effing es! This is amazing! I must print one, today!

I'm blown away! This is pure genius.

Watch the video -- it's awesome too.

My FF Dreamer gives 28 hours print time in given settings for the main dial part. Any suggestions?

this is definitely a tricky one to slice using simplfy 3d. It doesnt like the model as downloaded, so, I created my own stl from the SCAD and then repair the model using makeprintable.com which is fast becoming my goto fixing software, (its fixed everything so far!).
Then slice as normal.

Slice it in Cura. Had no trouble slicing it printed fine.

Thank you for this magnificent piece of work. Not only for the quality and clarity of your SCAD code but mostly for the example of how to rethink an existing concept. Take a bow.

Thank you for creating this!. I just printed the Gnomon. I am using a Makerbot Replicator 5th generation. I printed at a high resolution (1mm). I did print in white PLA. I am not concerned about the sun's heat issue since it is cold here, white is reflective and I am likely to just play with it and use my watch for keeping time.

I note that in the minutes slots there is enough errant strings to block much of the light. I am now sorting how to gently clip and remove those strands. Any ideas are welcome.

Would PLA be more likely to allow bits of string residues than ABS?

In theory can this be designed bigger to increase the time increments from 3 periods per hour (20 minute segments) to say 12 periods (5 minutes) or does the increased size increase the strand failure without support?

What if the gnomon was increased in size, sliced horizontally and each layer laser cut from plexiglass (or aluminum) and then stacked and secured... how about this and that.

I think someone said something about the benefit of printing the gnomon in sections. This would be helpful. I would like to be able to print the minute module alone or even the minute + final zero unit (which has no small strands). Anyway I'd like to experiment to produce a errant strand free print on the minutes module without having to print 22 hours each try. I am giving OpenScan a go but if someone cuts the gnomon up, I'd be glad for it.

Thanks for the thumbs up ! A few thoughts about your questions:

  • Maybe with a hot needle: hold a needle with a pair of pliers, heat the needle with a candle flame, and then use that needle to carefully cut both sides of each extraneous strand of plastic. Just don't drink too much coffee beforehand.
  • Stringing can usually be improved by tinkering with the hotend temperature, retraction settings, printing speed, PLA brand... It's usually slightly printer specific too, so maybe someone on a makerbot forum might have already done some research on it (?).
  • Theoretically: yes! Although you might also need to adjust a bit the other parameters at the same time: pixel size, pixel pitch, gnomon shape...

tout à fait génial! Je prédits une apparition dans les featured très prochainement.
J'ai bien hâte de voir la suite sur mojoptix . Merci d'avoir partagé ce modèle.

L'ingéniosité de l'homme ne cessera de m'étonner.

Brilliant - I cant wait to make this!

I'm getting a compile error "FLAG_draw_this_column = len( search(tx, ID_column_OFF) ) == 0;"
I'm on linux mint 17

That is odd indeed.
Could it be that your version of Openscad is older than 2013 ?
The function "search" was only added in the 2013.01 OpenScad release.

The stl's seem ok although sli3er said it had to fix it ??
Cura didn't have any problems at all. Here are some screenshots of the openSCAD's version
and the line throwing the error.



I managed to replicate the parser error with an earlier version of Openscad (2013.06 was the closest I could find for windows). After checking the Openscad release history, I believe this error might come from this:
"Before version 2015.03
It was not possible to do assignments at any place except the file top-level and module top-level. Inside an if/else or for loop, assign() was needed." (from https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/The_OpenSCAD_Language#Variables)
And I also noticed something even worse with that version: the Openscad editor would only open the first 425 lines of the .scad files (which is 823 lines long).
So maybe if you try the last version of Openscad (2015.03), it will all behave nicely again (hopefully) ? Let me know if that doesn't work.
And thanks for the heads up on slic3r. I've heard before that sometimes slic3r doesn't like much any Openscad files from countries that use commas as decimal separator. I'll check it out.

I have run into problems with mismatched versions of OpenSCAD before, too. The real issues start when they phase out the old code and replace it with more robust code. Old scad files not working in newer versions of OpenSCAD is a pain to track down. Anyone have any thoughts on how to prevent issues with this? I try to comment the version of OpenSCAD that I used to compile the code, but tracking down an old version is sometimes harder than doing a replace search on the new code (if you know what you're replacing and what has changed in OpenSCAD). I try to always keep my OpenSCAD updated to the newest version. Then I sometimes can't even recompile my own code from months past.

Thank you linux doesnt give many options I'll boot into windows instead and run it there.

brilliant !!!loved it

This really highlights how complex 3D printed objects can be with no additional cost to make. Thank you!

Brilliant. I think a useful addition would be to have openSCAD create a fixed angle base if you know your latitude (google your city and latitude). Then that part would not need to be adjusted.

This is an amazing thing with a wonderful contrast between old and new tech. :) Thanks for sharing the files!

Thank you all so much for your awesome feedback and kind words !!!
If you're curious about what sort of witchcraft is happening inside this sundial, then have a look at the link at the top of the page:
there is now an [ENGLISH] version of the tutorial video for this sundial ;)

Très étonnant ^^
Merci du partage.

Seriously. A true example of taking a classic invention and reinventing it.

A real "I wish I had thought of that" moment.

golf clap

Brilliant ... magical!

in one word ---just awesome! well done! and thanks for sharing ;)

That's like 8 words, but I agree totally!

Hat off for this great creation.

I'm having great trouble getting the gnomon to print correctly. Your mesh is the problem. All off my slicer's are printing a solid layer about 7-8mm from the bottom. I tried repairing the meshes with multiple software and cannot get this to come out right. Any suggestions/repairs? I am printing at .1mm layer height with a .4 nozzle.

I'm seeing the same thing. Simplify3D reports that the STL is not manifold. NetFabb's online STL repair fails on the file, so there's definitely an error in there somewhere. I get a solid layer around 8mm which ruins it. I see issues with Simplify's slicer and the Dremel slicer.

That is odd indeed, there is nothing special happening at 7-8 mm.
I doubled checked the STL files for both gnomons on thingiverse with Cura (to make sure there wasn't any sort of corruption in the upload), and they both seem just fine.
Let me try to replicate what you see. Which slicer are you using ?

I found the solution. I had to repair with netfabb, then repair in Simplify3d with certain fixes (not all), then I had to adjust my FFF settings to ignore mesh/layer problems.

I am glad you managed to sort it out !
But I am still really curious to understand why you'd need to repair the mesh at all. So I've tried to reproduce this 'solid layer' issue with Cura and MatterSlice, with your printer settings (a Robo R1, right ?). But still no luck: it all looked perfectly fine on the layer-by-layer views.

So maybe it is simply that I didn't correctly understand your issue (?). By "bottom": do you mean the (horizontal) "printing plate" or the (vertical) "end of the gnomon with a round hole for a screw" ?
If it's the latter (and this 'solid layer' is also vertical), then could it simply be some support material ?
If it's the former, I would be curious to try with the slicers you've also tried...

Simplify3d definitely gives an issue, and I can't seem to find a combination of settings to just print the model as is and not try and make it manifold. Skeinforge did similar when I had "correct mesh" selected, but with "unproven mesh" I think it ay be better. I have a few other options for things still enabled I need to kill to see if it makes it so its obviously working.

If someone has this working in simplify, please post which options are the right options :)

Thinking about this some more... (it's so cool, I'm captivated)...

I'm thinking that it would be convenient to place the gnomon vertically, say standing on a window sill, or stuck to a window. If the slots for the "pixels" were made at 40 (or whatever latitude you're at) degrees to the long axis of the gnomon, then they'd be in the right orientation to the sun when the gnomon was vertical.

Could the "angle" of the gnomon be virtualised and incorporated into the OpenSCAD script? (In this case, it would be sensible to make the gnomon a customizable object in Thingiverse).

So I'm thinking something like programmatically rotating the gnomon by 40 degrees and then flattening the top and bottom. But, looking at the code, I think it might be just a matter of setting the right value in direction_angle_y, and/or pixel_wall_angle_y before calling extrude_character?

An indoor sundial! I like it!
In the script, the X direction is along the gnomon main axis. So you would have to tinker with direction_angle_x (pixel_wall_angle_x defines the angle between the two walls in the x direction, it is currently set to 0).
There was a "tiny" bit of trial and error to find the best gnomon size and shape, pixel size and pitch, timing of the transition between displayed numbers... Most geometries required to remove too much material inside the gnomon, and then gave significant display errors. This visual checking is a tedious process but it's visually obvious when it's a working design. However I am not sure how to automate this in a customizer.
Nonetheless I really like the idea, I'll try to whip up something that can be printed.
I am almost done with the editing of the english version of my video. It might give an even clearer idea of how this sundial works.

Belle et éloquente.

Très impressionnant ! BRAVO et merci.

Mind blowing. I want this, but I'm not sure I can print it as is, so I have a question: I think the answer is yes, but if I break the main arm up in to the separate digits and print them at a larger scale (my printer has a 0.4mm nozzle and prints at a 0.14mm layer height) and then glue them back together, it should still work right?

If you do this, please share the STL for those of us with smaller printers.

Incidentally, I printed one, scaled down to 53%, to make it fit diagonally on my 100x100 printer. That worked, kindof. The hours is about right, but the minutes not so good. I can see where there's some threads that didn't print, and some holes that are filled.

Doh, I now also need a 53% scale jar to mount it on. lol

KISSlicer on my (older) Ubuntu box SegFaults on the original file. I used TinkerCad to chop the minutes off - KISSlicer is estimating 15 hours (at 10mm/S) to print just the 2 hour digits at 100%. Might try printing it this weekend.

Indeed, that should still work.
Maybe just a suggestion: make sure you don't have any noticeable under-extrusion.
Most of the swiss cheese structure is made of a zillion horizontal strings of plastics: they are all very thin 5mm-long overhangs. So scaling-up the model will also make these overhangs that much more challenging to print. Or in other words: "under-extrusion is evil !"
Have fun !

That's absolutely brilliant!

Super idee.

Hate de voir avancer ton blog.


Very cool! Does it work in the Southern hemisphere?

Yes !
You just have to print the correct .STL file for the gnomon: 'Gnomon_Southern.stl' (instead of 'Gnomon_Northen.stl').
(If you were to use 'Gnomon_Northen.stl' in the Southern hemisphere, you would actually see time going backwards: start at 16:00 and finish at 10:00.)

There will only be one tiny difference :
In the pictures and video above (taken in the Northen hemisphere with 'Gnomon_Northen.stl'), the time is written (inside the shadow) from the glass jar base toward the tip of the shadow.
In the Southern hemisphere with 'Gnomon_Southern.stl', the time will instead be written from the tip of the shadow toward the glass jar (so you will have to stand on the other side of the white table in this video to read the time from left to right).

Enjoy your summer ;)