[MOC] Fully automatic Clock

[Gonkius]

This is a fully automatic clock that was finished end of 2014. So, why do I call it "fully automatic"?

- The clockwork runs as a normal mechanical clock with a pendulum and counterweight.

- There is a motor that winds the clock every hour.

- The speed of the clock is adjusted once a day using the Mindstorms unit. The speed is adjusted by changing the length of the pendulum.

In total, the clock runs for itself without any assistance, and it shows the right time, even if it is build using only LEGO bricks. (Apart from the string to the counterweight)

There have been many challenges in this design. My main focus, except the obvious goal to make everything to work, was to make this as compact as possible. The whole clockwork fits inside 14x14x14 studs.

I did a short video to show the "action":

The two sensors are used for:

1. Stop when the counterweight is fully winded

2. Give feedback from the minute hand rotation back to the Mindstorms unit.

The counterweight is made out of 12 train/boat weights and is about 0.68kg.

Winding is done through a differential to avoid interruptions during the winding.

There are two medium motors inside the clockwork for the winding and adjustment.

The Mindstorms unit is hidden in the base behind a hatch:

WIP pictures

Specially designed differential gear to reduce the friction between the counterweight and clockwork as much as possible. The winding motor rotates the large turntable gear:

Clockwork prototype, without any automation:

Very first prototype of the escapement:

Edited August 25, 2015 by Gonkius

[zver]

Great work!

I like the speed adjustment mechanism especially.

Are you going to make the NTP synchronization? ;)

[timslegos]

Now thats a great use of technic! My only critique would be to cover up the small LA so that it is as clean as the clock face. Also, how do you set the time?

Tim

[Gonkius]

zver: The NXT don't communicate very well to the Internet, so an upgrade to EV3 is necessary to talk to a NTP server.

timslego: I tried to cover the actuator, but I didn't manage to get a design that didn't look bulky. The hands are connected to the remaining gears through white 24T gear with clutch so the hands can be adjusted if needed.

[Alasdair Ryan]

I really like this moc,good job.

[BusterHaus]

Nice work, it's very functional and looks good, too. How big is the correction every hour? And is it consistent? Do you think the correction could be done mechanically, without the NXT unit?

[KirTech LAB]

Fantastic creation!!! Very realistic mechanism!

[zux]

Nicely build, I like it a lot! Did you have a chance to test/calculate how long it will work on single battery charge? Would it be possible to incorporate a solar panel for "infinite uptime" ?

[lcvisser]

That is very cool. Really ingenious and seems to work really well. I'm also curious to know how accurate it is on an hourly basis.

[imajor]

This is incredible, grats. Any plan for sharing building instructions?

[Rockbrick]

very compact and great idea to use the mindstorms for regulation and winding

[Gonkius]

The error is in the range of 2s/h according to my measurements (Without correction). The actual adjustment done by the software is not known as I don't log this... I guess it is very sensitive to temperature changes, but I've not made any measurements on this. I'm investigating to use the Mindsensors real time module to get an even better time reference, but I need more data to tell how much correction that actually is used over a longer time. In the next software version I'm working on it will display more statistics regarding how much adjustement that was applied over longer time.

The clock only runs a few days using batteries. I have now added an external power supply to run continously. Good idea to add a solar panel, (oerhaps the one that LEGO have done), I doubt it will be sufficient, but I will make some calculations. Here in Sweden, the days are short and dark during wintertime...

BusterHaus: To be able to adjust the time mechanically, you would need a better mechanical time reference than the clock itself, that is similar to lift yourself in your hair...

No plans for instructions, sorry, this would be really complicated, at least for the complete clock. Bút you have the pictures ;) If anyone would like to see any special details, let me know.