We introduce MechSense, 3D-printed rotary encoders that can be fabricated in one pass alongside rotational mechanisms, and 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 but can be seamlessly integrated during design and fabrication. Our MechSense editor allows users to integrate the encoder with a rotating mechanism and exports files for 3D-printing. We contribute a sensor topology and a computational model that can compensate for print deviations. Our technical evaluation shows that MechSense can detect the angular position (mean error: 1.4°) across multiple prints and rotations, different spacing between sensor patches, and different sizes of sensors. We demonstrate MechSense through three application examples on 3D-printed tools, tangible UIs, and gearboxes.

This work introduces “destaining” as an interactive component for the HCI community. While staining happens unintentionally (e.g., spilling coffee), destaining can be used as an intentional design tool that selectively degrades stains on textiles. We explore the design space using silver doped titanium dioxide (TiO2/Ag), stains and light as a set of design primitives for interactive systems. We then developed replicable and accessible fabrication and testing methods that enable HCI researchers and designers to upgrade various fabrics to self-destaining textiles. Next, we demonstrate a Self-deStaining textile interface with embedded Light Emitting Diodes (LEDs) and moisture sensors that activate cleaning. Lastly, we showcase how the textile can be used in everyday objects such as self-cleaning clothes, a patterning station for phone cases, and accessories that change patterns and colors based on the user’s experiences.