Ancient Greek Lego Computer
by Tim Moran
In a previous life, when I edited a technical newspaper for electronics engineers, there was always something of a feud between the analog and digital designers. One epic throwdown concerned tube amplifiers vs. digital sound. As I recall, it got very ugly. Since then, analog computing has held great interest for me, so it was with much delight that I learned about a thoroughly modern digital engineer who recreated an ancient analog computer--out of Legos.
Andrew Carol is by day an Apple software engineer working on OS X; by night he's a Lego genius who created a working replica of the ancient Greek Antikythera Mechanism, circa 100 B.C., which was designed to predict astronomical events, such as eclipses.
An incredible stop-motion video discusses the history of the Antikythera and shows the design's inner workings. According to the video, the device was lost for more than 2000 years, until, in 1901, divers discovered it under the sea off Greece. Fast forward 100 years, at which time high-resolution x-ray tomography showed that the ancient Greek engineers had devised a unique "computer," using gears of great precision, to predict celestial events with uncanny accuracy.
In 2010, Carol decided to make a fully functioning replica out of children's building blocks--1500 Lego Technic parts and 110 gears. It took him 30 days to design, prototype and build the machine. He says, "The Greek guy who made the original could cut his own metal gears to the exact ratios he needed, so he only needed 50 or 60 gears total. . . . But I have to use the gears and ratios that Lego happens to make. That's why I might need eight gears to accomplish a bit of math that the original machine accomplished with two. My machine uses about 110 gears, and 7 complete differentials, to do most of what the original one did."
For someone who spent many an hour playing Legos with my boys when they were young, and whose biggest accomplishment with them was to make a cool tower, Carol's feat is one of wonder and awe.