A Design and Fabrication Pipeline for Integrating Rotary Encoders into 3D Printed Mechanisms

Abstract

In this thesis, we introduce MechSense: rotary encoders 3D-printed in one pass alongside rotational mechanisms. MechSense encoders report on their angular position, direction of rotation, and speed. MechSense encoders utilize capacitive sensing by integrating a floating capacitor into the rotating element and three capacitive sensor patches in the stationary part of the mechanism. Unlike existing rotary encoders, MechSense does not require manual assembly and can be effortlessly integrated during design and fabrication. MechSense is accompanied by an editor that allows users to integrate the encoder within a rotating mechanism.

We contribute a sensor topology and a computational model that can compensate for print deviations. We also evaluate our sensing model for angular position detection (mean error: 1.4°) across multiple prints and rotations, different spacing between sensor patches, and different sizes of sensors. Finally, we demonstrate MechSense through three application examples on 3Dprinted tools, tangible UIs, and gearboxes.