Integrating Electronics into the Physical World
MIT researchers have successfully integrated 'breadboards,' commonly used flat platforms for electronic prototyping, directly with physical products. The goal is to provide a faster and more convenient way to test circuit functions and user interactions with products such as smart devices and flexible electronics.
Breadboards are rectangular boards with holes on their surface, featuring metal connections and contact points between most of these holes. Engineers can connect components of electronic systems (ranging from basic circuits to complete computer processors) to the desired holes. Subsequently, they can rapidly test, rearrange, and retest the components as needed. However, breadboards have remained largely unchanged for decades. As a result, testing how electronic parts, such as those in wearable devices and various smart gadgets, will look and feel has been challenging.
In a paper presented at the CHI (Conference on Human Factors in Computing Systems), researchers describe 'CurveBoards,' outlining the structure and function of a 3D-printed object integrated with a breadboard. Specialized software automatically designs objects with distributed pinholes filled with conductive silicone to test electronics. 
CurveBoards enable designers to experiment with component configurations and test interactive scenarios during prototype iterations. In their studies, researchers 3D-printed CurveBoards for smart bracelets and watches, frisbees, helmets, headphones, teapots, and a flexible, wearable e-reader.
Special Software and Hardware
The fundamental component of CurveBoard is a custom-designed layout software. Users import the 3D model of an object, then select the 'create pinhole' command, and the software automatically matches all pinholes along the object. Users can then choose between automatic or manual layouts for connection channels. The automatic option allows users to explore different connection layouts across all pinholes by clicking a button. For manual layouts, interactive tools can be used to select pinhole groups and specify the type of connection between them. The final design is exported to a file for 3D printing.
When a 3D object is loaded, the software forces its shape into a 'quadmesh,' where the object is represented as small square groups, each with separate parameters. In doing so, it creates a consistent gap between the squares. Cones, tapered holes with a wider base on the surface, will be placed at each point where the corners of the squares touch. For channel layouts, some geometric techniques ensure that selected channels join desired electrical components without intersecting. In their studies, researchers 3D printed objects using a flexible, durable, non-conductive silicone. To provide connection channels, they created a special conductive silicone that can be injected into the pinholes and flows through the channels after printing.
To validate CurveBoards, researchers printed various smart products. For instance, headphones equipped with menu controls for speaker and music streaming capabilities. An interactive bracelet included a digital display, LED lights, a photoresistor for heart rate monitoring, and a step counting sensor. A teapot featured a small camera to monitor the color of the tea and colored lights to indicate hot/cold areas. Additionally, they printed a wearable e-book reader with a flexible screen.
Better, Faster Prototyping
In a user study, the team investigated the benefits of CurveBoards prototyping. They divided six participants with different prototyping experiences into two groups: one using traditional breadboards and a 3D-printed object, and the other using only a CurveBoard of the object. Both groups designed the same prototype but switched between sections after completing designated tasks. In the end, five out of the six participants preferred prototyping with CurveBoard. Feedback indicated that CurveBoards were generally faster and easier to work with. However, researchers emphasize that CurveBoards are not designed to replace breadboards but rather function within the "middle accuracy" between initial breadboard testing and the final product in the prototyping timeline.
Later, researchers hope to design general templates for common objects like hats and bracelets. Currently, a new CurveBoard can be created for each new object. However, ready-made templates will allow designers to quickly experiment with basic circuits and user interactions before designing specific CurveBoards.
Additionally, researchers aim to move some early-stage prototyping steps entirely to the software side. The idea is to enable individuals to design and test circuits, and possibly user interactions, on a 3D model generated entirely by software. After several iterations, a more refined CurveBoard can be 3D printed.
