[ekaggrat] designed a 3d-printed clock that’s fairly simple to make and looks awesome. The clock features a series of 3d-printed gears, all driven by a single stepper motor that [ekaggrat] found in surplus.
The clock’s controller is based around an ATtiny2313 programmed with the Arduino IDE. The ATtiny controls a Darlington driver IC which is used to run the stepper motor. The ATtiny drives the stepper motor forward every minute, which moves both the hour and minute hands through the 3d-printed gears. The hour and minute are indicated by two orange posts inside the large gears.
[ekaggrat] etched his own PCB for the microcontroller and stepper driver, making the build nice and compact. If you want to build your own, [ekaggrat] posted all of his design files on GitHub. All you need is a PCB (or breadboard), a few components, and a bit of time on a 3D printer to make your own clock.
I love the design! It’s crying out for a lasercut adaptation, though.
Without a crystal or RTC, though, it seems likely it’s going to keep really terrible time.
Or perhaps an escapement?
the attiny on the internal oscillator is fairly accurate enough for this clock..
According to the datasheet it’s within 10% factory-trimmed, which means it would lose or gain up to 2.4 hours a day!
i have tested it for a week…and it has not lost more than 2 -3 minutes … … anyways i will upgrade it to a crystal soon..
I’m guessing he could do manual trimming of the crystal in his code to make it more accurate in lieu of adding an external crystal. After that, most variation would probably be temperature dependent.
Why dont you try it before you knock it?
Well, first of all it was intended as constructive criticism.
As for why I don’t try it – the datasheet makes it abundantly clear that the internal oscillator will not be sufficiently accurate for a clock over extended periods and in different temperatures. If it were possible to make sufficiently accurate RC oscillators, nobody would use watch crystals.
Really? You find +/- 1% (best case) is accurate for a clock? You really think 864 seconds deviation per day is in any case useful?
Nice build ekaggrat. While I agree that it might need a slight modification to increase accuracy I’m not going to jump down your throat about it (like others here).
thanks for the backup
OK you are right. I did not want to be rude. But I was. Sorry for that. This clock really IS a beauty and you should spend some effort to make it as accurate as possible. Which you already said is going to happen. So sorry again for being unreasonably harsh.
@xnalpf
you were just pointing out the weakness thanks for that .. will upgrade it in the next instance…
Well.. no. The datasheet [0, p25] says that the internal oscillator’s accuracy is +/- 10%, so expect more than 5 minutes per hour deviation. I wouldn’t use it as my alarm clock, even when calibrating it to 2% accuracy.
32kHz crystal oscillators such as used in everyday clocks typically have an accuracy of +/- 20 ppm, 5000 times more accurate.
well as i said i have had it working for a week with 3 minute error at the end of the week ( i was curious to see the accuracy )…. thanks for the behind kicking…. i will put the crystal in … HAPPY?
There’s rarely anything anyone can say which will go down with everyone. That’s the way it goes in the comments-secion of HaD these days, or so it seems. Don’t get too worked up about it, it’s not worth the energy.
I personally think it’s a lovely build: the clock looks good and a 3-minute error sounds like a pretty accurate clock for its part count.
This is an amazing build, don’t let anyone bring you down about it. It’s interesting, well built, and imaginative. Keep up the good work.
Just a suggestion: a printed clock face of some sort might make the clock easier to read, if you wanted to go that route. This is only a suggestion, not criticism.
Part of it is the amount of resolution for the trimming, and part of it is to account for variation in process, voltafge and temperature (PVT). Then there is the Scotty fudge factor so you don’t toss out otherwise usable batches of chip and the usual CYA. In reality, you should be within +/-1% just from factory calibration as you are not likely to be at the corner cases for PVT.
+/- 20ppm for a gear clock should be fine as it falls in the resolution of how you read it anyways. If you want to play with temperature compensation, those guys with the TI MSP430 watch managed to trim it down to a few seconds a year.
This is a great build. excellent work. Can’t wait to get my printer next month to start making this clock. Ignore the 1st world complainers on the oscillator. This isn’t intended to be an atomic clock. a few minutes per week adds to its charm. Keep up the good work.
Any chance you will sell the kit ? not all have access to the needed equipment to make a kit
can do a one off on special request .. mail me.. ( ekaggratatgmaildotcom)
Sent, thanks
noamr$beyondsecurity!com
beautiful! that is all I have to say.
Wonderful build! I like the colors and the construction!
Of course there will be an inaccuracy with the built-in oscillator but I bet that [ekaggrat] already knew that before posting the project..
What I wonder is how loud it is?
as loud as a sms buzz every one minute
That’s very stylish! Not surprised to see that [ekaggrat] appears to have an architectural background.
Also happy to see this was described accurately, as “an ATtiny2313 programmed with the Arduino IDE”, rather than simply called an Arduino.
thanks and a good guess
Mm. how about a feature where you could position a laser etched round piece of acrylic in the center in one or two small acrylic extentions. That would be a freaky faceplate.
http://www.clocksbysid.com/images/FLOATGINGHANDSCLOCK.JPG
yes thought of that but left it out for simpicity
That is one beautiful clock – amazing build!
What CAD software did you design it in, that exploded diagram looks really good too. I’ll be adding this to my “to-make” list, thanks for sharing!
all done in rhino3d with grasshopper for the gears and vray for the render
I can’t help but think that this could be the basis for a Stargate clock.
Or Halo for that matter. Can you imagine two Master Chiefs chasing each other around the clock?
Pretty.
This is the first 3d printed project on HAD that has inspired me to fire up the makerbot and try out!
Awesome design, i can’t wait to have it ticking away on my desk, though after reading some of the comments I might try to experiment with a different oscillator…
I was curious if you considered adding a second-hand ring to the clock, and if you decided not to include one, why not?
i did make a mechanism to have a 3rd ring but it just made it bulky and the friction of the gear train was adding up.. Besides you don’t want a stepper motor going burr burr in the middle of the night..:)
True about the stepper motor running all night. I’m sure adding a seconds-gear would require adjusting the design to use some other low power constant motor or other similar mechanism… like some sort of clock haha
I fully understand the issue of gear friction, there’s obvious limits to what we can do with the tolerances of 3d printed parts. Even with just minutes/hours, awesome project, ekaggrat, thanks!
working on a electro mechanical pendulum version but damn the friction ,,,, a sneek peek
http://imgur.com/GhZHIkD
Have you tried a nylon filament?
… how about a weight driven wall clock… that would really annoy the accuracy police.
You are keeping time in the microcontroller not mechanically. The clock can always go to sleep and catch up to the right time in the morning.
no the micro controller is working in dumb mode… just pulses the motor at reqular intervals without knowing where the rings are .. so you turn of the clock it looses track of time…
…but as tekkieneet suggests it might be an interesting addition to have a “sleep” mode, with the micro able to drive the stepper to a specific time. Hooked to a GY-521 and could wake on tap outside normal sleep times.
Great design ekaggrat, thanks for sharing!
I’m reminded of an episode of Northern Exposure, where Maurice bought an antique clock – then got upset that it didn’t keep perfect time. If you focus on the imperfections to the point that you can’t see the beauty, you don’t deserve to own it. http://www.imdb.com/title/tt0662377/
Did you have difficulty getting the 3D printed rings to stay round and straight as they cooled?
printed with pla on a heated bed … abs warps badly and wont print without brim…. so avoid it.
Argghh. I’m running out of excuses to keep from buying/building a 3d printer. Very cool & if you want to *really* annoy people, just run it via an old synchronous motor like a 70’s(ish) flip clock
Now suddenly, I see a printed grandfather flip clock clacking away the mins
i always wanted to make a flipclock but cant get a basis to tart with …any links to plans/diagrams/ 3d models of flipclocks?
Sadly, no sources of dxf/stl/?? that I could find. Amazon and company list flip clocks that could be used as donors/models of the drivetrain.
to make things worse, I was just contemplating woodFill/Laywoo-D3 vs “normal” plastic colors contrasting with local red cedar open “frame”. Then there’s always steam motif w/the metallic filaments. (too many ideas and too little skill, sorry)
I love this concept. If I had access to a laser cutter, then clear acrylic would be my material of choice, with perhaps transparent hands with black dots and tiny luminous circles on the tips and some carefully placed LEDs for subtle illumination.
Having said that I love this design, and the choice of colours. As for accuracy… the nay sayers can use their smartphone, laptop, wristwatch, TV…. you simply can’t get away from millisecond accuracy these days.
at this size the laser cut gears will not be as good…