DUET: A Kinetic Sculpture

When I'm not creating music, I can always be found creating something else! I was super drawn to Legos as a child, and now I've rediscovered them as an adult. As part of this fun hobby I built a kinetic sculpture, DUET, in celebration of the Aurora School of Music’s spring recital series. This sculpture features a pianist and violinist playing together. The pianist’s arms move up and down the violinist rotates in place.

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The pianist is the most dynamic part of the sculpture and was the most difficult to build! It takes a few simple machines to get it up and running. Inside the sculpture are two weights that rise and fall, each is responsible for the motion of a different hand. The weights are lifted by prongs sticking out of two small wheels. As the wheels rotate, they cause the weights to rise. Once a prong moves past the weight  — because of the wheel’s rotation — the weight drops down. Thanks gravity!

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Each weight is attached to a loop of string (courtesy of some Christmas ornaments). When a weight drops, this causes its loop of string to yank down on a lever inside the piano. When this lever is yanked down, a piano key quickly flips up, causing one of the pianist’s arms to bounce in the air. In this sculpture the piano plays the pianist!

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The violinist sits on top of a big gear that can spin freely. Its back-and-forth rotation is caused by the movement of a grooved Lego piece—one with teeth that fit the side of the gear. The grooved piece itself moves forward and back because it is attached to a rod being cranked by a small gear.

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Lastly, the speed of the sculpture is controlled by an early-2000s era LEGO train controller. Ta-da!