A Lego Replica of the Antikythera Mechanism

vbraga writes "The Antikythera Mechanism is the oldest known scientific computer, built in Greece at around 100 BCE. Lost for 2000 years, it was recovered from a shipwreck in 1901. But not until a century later was its purpose understood: an astronomical clock that determines the positions of celestial bodies with extraordinary precision. In 2010, a fully-functional replica out of Lego (YouTube video) was built."

Comments

I must have this!!

[erroneus]

I need a parts list and build instructions. Anyone know if they did this? All we got was a Youtube video...

Re:I must have this!!

[JaZz0r]

Andrew Carol is the designer. His website has more information - http://acarol.woz.org/antikythera_mechanism.html If the site is down, try the Google cache

Re:I must have this!!

[TheMidget]

.... which also shows that it is not a replica of the Antikhera mechanism. It achieves the same purpose (predicting eclipses), but using a different mechanism, because they needed to work with gear ratios achievable with available Lego pieces, and thus needed to add differentials, whereas the Greeks had no such needs (making their own gears, so being able to directly use whatever ratio was needed). Moreover, display differences (4-wind spirals versus 5) introduced more differences in the multiplicative constants, and thus the mechanism:

Because it would be difficult to fit the information for 223 lunar months in a single rotation of a dial, the original machine used a 5 wind spiral to encode the information. This made more space available for the markings required for the eclipse information.

My version of the machine uses a 4 wind spiral. This provides the same benefit as a 5 wind spiral but matches the Full Moon Cycle which may permit future enhancements to accuracy.

This change results in the formula:

Saros4 = Y * 4 * 235 / (223 * 19)

I decided to not use the Corinthian calendar and instead use the standard Gregorian civil calendar in a four wind spiral representing the four year leap year cycle.

Noting that 235 is 5 * 47 and 254 is 2 * 127, the important constants for the construction are:

4, 5, 19, 47, 127, and 223.

The readily available high quality LEGO gear ratios are combinations of 1, 3, and 5. With some challenge 4 is available. With these combinations we can get to gear ratios which are multiplicative combinations of these values. The easy ratios we can get to include: 1, 3, 4, 5, 9, 12, 15, 20, 25, 27, etc.

Ratios of 19, 47, 127, and 223 are impossible to achieve with simple gear ratios because they are prime numbers. We have to look beyond simple gears to differentials.

Re:I must have this!!

[AmberBlackCat]

It would be nice if I walked into a toy store and saw a Lego set with this on the front of the box instead of a Star Wars ship.

Re:I must have this!!

[Tablizer]

It would be nice if I walked into a toy store and saw a Lego set with this on the front of the box instead of a Star Wars ship.

It doesn't have to be mutually-exclusive: A Millenium Falcon can be made to predict eclipses. Of course you need a Wookiee to bang on it when it jams.

See "The Making of" too

[wiredlogic]

Not to be missed is the time lapse video of the process of creating the video which was as fascinating as the model itself.

my scientific observation

[Tumbleweed]

"A device is not truly understood until its function can be duplicated by Legos."
- Tumbleweed's Observation

Re:my scientific observation

[jcr]

I think I understand how an oxy-acetylene torch works, but I don't think I could duplicate its function with legos...

-jcr

Re:my scientific observation

[Anonymous Coward]

I think I understand how an oxy-acetylene torch works, but I don't think I could duplicate its function with legos...

Well, you can duplicate its function with bacon. That also counts.

Re:So...

[neokushan]

No, you idiot, that's obviously not how it works. If you find a bug in this, you cause the entire celestial system to collapse in on itself, killing us all!

More Information

[breser]

Built by Andrew Carol who is an engineer for Apple.
He had a website about his building complex lego machines at: http://acarol.woz.org/
And specifically information about this one at: http://acarol.woz.org/antikythera_mechanism.html

Unfortunately, the site seems to be down but Google still has a good cache:
http://google.com/search?q=cache:acarol.woz.org/antikythera_mechanism.html
http://google.com/search?q=cache:acarol.woz.org/acarol.woz.org

Re:More Information

[madmayr]

Ahh, yes. The slashdot front page effect. Funny how that works.

maybe we should build a slashdot-effect-machine out of LEGO

Antikythera Reconstruction ?

[Anonymous Coward]

This has as much to do with the Antikythera mechanism as a software simulation. The mechanism has no differential gears, which are used on this lego construct because its creator played with them during his experiments with Babbage's Difference Engine. The beauty of the Antikythera machine lies in its pin-and-slot mechanism for modelling epicyclic trajectories which are of course nowhere to be found in this "reconstruction".

Re:As opposed to

[AHuxley]

http://en.wikipedia.org/wiki/Berlin_Gold_Hat ~ bronze age pda (personal duration assistant?) meets lunisolar calendar meets bling sun cult headdress?

NOT a replica

[Gravis Zero]

it's an implementation of the same math that that the Antikythera mechanism does but it's done in a completely different fashion.

Woz explains the device on his own page as well as the math behind it: http://acarol.woz.org/antikythera_mechanism.html
There is also an article about his LEGO device: http://www.fastcodesign.com/1662831/how-one-engineer-redesigned-an-ancient-greek-mechanical-computer-out-of-legos

more information about the Antikythera mechanism can be found here: http://en.wikipedia.org/wiki/Antikythera_mechanism

As opposed to abacus

[mangu]

is there an even earlier computer that was in some way un-scientific?

Certainly, the abacus is much older and was used for business, as opposed to scientific, calculations.