3D printers are incredibly useful tools for rapidly prototyping mechanical parts, but they are rarely used for anything electronic. The vast majority of 3D-printed parts are made of PLA or ABS—both of which are thermoplastics. It is, however, possible to print electrically-conductive material on everyday hobbyist FDM (Fused-Deposition Modeling), also called FFF (Fused-Filament Fabrication), 3D printers. Researchers from Australia and Germany have developed 3D-printable tactile pixel inputs called Tactlets that take advantage of that material.
These Tactlets can be made on most 3D printers with dual extruders, and the research paper describes their usage and the digital fabrication techniques needed to produce them. A Tactlet is made up of one of more “taxels” (tactile pixels), each of which is capable of sensing touch input. Different shapes and arrangements of taxels can be used to form a Tactlet, and those can be tailored to suit particular applications. For example, a linear arrangement of taxels can be used to create a volume control Tactlet. The researchers created an add-on tool for Rhino3D CAD (Computer-Aided Development) software that can be used to place various Tactlet styles onto complex 3D shapes.
During 3D printing, each taxel is embedded with a point on the surface made from conductive filament. A conductive trace runs from each taxel to a part of the model that is accessible so it can be connected to a microcontroller. From there, standard conductive or resistive touch circuits can be utilized to detect when the taxel is touched. The microcontroller can be programmed to detect exactly how a Tactlet is being touched, so it can register a sliding motion compared to a simple tap. It’s even possible to print Tactlets onto paper using an inkjet printer equipped with conductive ink cartridges. Tactlets may not be groundbreaking, but they could provide designers with an easy method for adding tactile controls to their creations.