It’s hard to watch this video and not have your head explode with all of the possibilities for what you can do with a conductive spray-on material that can turn just about anything into a touchscreen interface. The technology is being developed at The Future Interfaces Group (FIG), an interdisciplinary research lab at the Human-Computer Interaction Institute, Carnegie Mellon University.
Here, Yang Zhang, one of the 2nd year Ph.D. students working on the project, explains its basics:
Electrick is a low-cost and versatile sensing technique that enables touch input on a wide variety of objects and surfaces, whether small or large, flat or irregular. This is achieved by using electric field tomography in concert with an electrically conductive material, which can be easily and cheaply added to objects and surfaces. We show that our technique is compatible with commonplace manufacturing methods, such as spray/brush coating, vacuum forming, and casting/molding, enabling a wide range of possible uses and outputs. Our technique can also bring touch interactivity to rapidly fabricated objects, including those that are laser cut or 3D printed. Through a series of studies and illustrative example uses, we show that Electrick can enable new interactive opportunities on a diverse set of objects and surfaces that were previously static.
As Yang points out, the technique is achieved through electric field tomography. A series of electrodes around the interface surface pass a small amount of electric current into the conductive layer. Voltage is then measured at all of adjacent electrodes. When a finger touches the surface, some current is shunted, causing a reduction of voltage at the contact point. Cross-sectional measurements around the surface are taken, and using electric field tomography, the exact location of the touch can then be calculated.