The Digital Fern

For my XYZ and Nature of Code final, I propose to make a robotic fern that will adapt and reposition itself to follow a light source. This arm will have several points of articulation in order to replicate an “unfurling” appearance.

One of the challenges of having a limb with several controllable joints is that there needs to be a motor controlling each one of them. This can add a problematic amount of weight, so I will explore the use of hydraulic pumps, in the form of syringes, or using a tension cable-driven system. This allows the motors to be located off the arm keeping it relatively light.

This video is somewhat of a proof of concept. One challenge I will have to work through is supplying enough strength in the motors to actually move the arm. I also intend to see if there are any benefits to using water vs. some kind of hydraulic oil. Either way, the hydraulic pump method may help me satisfy my first condition outlined in this post, to move in a surprising way.

As for the actual job of this arm, I would like it to be heliotropic, i.e. follow a light source. This will ultimately be more of a software solve, but I intend to use a series of light sensors to sniff out the source of the light. The arm can then use that data to optimize its angle to point directly at the light source. This can also be a source of interactivity.

Stay tuned as I continue to develop the concept.

References images:

A light installation with articulated “petals” made by Patten Studio


A robotic arm that draws pictures on your latte


A robot arm with an octopus tentacle for a hand

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