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Entropy Machine

Mechanism Design/CAD

Entropy Machine

This is a story about chaos and order told through the interaction of gears. Among the intricate relationship of these mechanical parts lay a luminescent sphere that witnesses the interchange of chaos and order. As the gears turn and drive the triple pendulum surrounding the sphere, they cast a retraceable trail of light upon the sphere's surface, thus creating a seemingly random pattern from logic. 

2020SP.DP2.Mechanism Project(2).Liang_Da


We started by investigating different types of mechanical interaction, looking for ways in which gears move in reverse directions, various speeds and time frames. 

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Initial Modeling/Testing

In the initial Modeling stage, we tested out the different mechanisms that would potentially make up the final design.

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Final Sketch/Model

After brainstorming and testing, we finalized the material and mechanical interactions for the final design.

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Computer Simulation/CAD

We constructed the CAD models to fully visualize the dimensions of this machine as well as the necessary parts tp be fabricated. We also tested out the operation of the mechanism through Solidworks by adding constraints to the model



Based on the model, we started our fabrication and assembly process. We used 3D printing technology in producing the custom designed gears and rails.

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This video illustrates the driving mechanism of the triple pendulum that creates the chaotic motion and makes up the central part of the machine.


To elaborate upon the narrative of logic, we further attached a compound rack and pinion which is composed of two gears of different sizes rotating on their respective track while sharing a common axis. This effectively reverses the directions of the gear by changing the torque output.

The central sphere is attached to one of the pendulum arms and is in the center of the chaotic motion. It acts as a canvas that captures the motion of the innermost pendulum arm.


The mechanism is powered through a step motor that is mounted on the based and connected to the drive train to increase the torque.

There are three major tracks that provide rotational motion for the pinions attached to different levels of the sphere. They transfer energy to the gears and eventually to the spinning pendulum.

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