A Touch of Gold - Spraying and Electroplating 3D Prints to Create Biocompatible On-Skin Wearables

Iterative design cycles for tangible user interfaces and wearable devices require efficient prototyping techniques to optimize development and to elevate the overall design efficacy. A key challenge for rapid prototyping techniques such as cardboard prototyping, 3D printing, or laser cutting is the integration of conductive surfaces. Additional wiring, conductive paint, or special materials like conductive filament often lack the necessary high conductivity and sufficient durability for designing on-skin wearables to measure muscle activity or to electrically stimulate the skin and muscles. To solve this problem we propose to combine spraying and electroplating to create surfaces that exhibit high conductivity, are solderable, corrosion-resistant and skin-friendly, and embody both practical functionality and aesthetic value. In this paper, we describe an effective spraying and electroplating process for rapid prototyping and demonstrate its applicability using several examples of tangible user interfaces. Further, we discuss advantages and disadvantages and describe limitations of the approach.