Prosthetic arms and legs of the future will have tactile sensitivity as a feature, but a lot of work still has to be done to get there. A couple issues that have proven to be engineering challenges is how to cover complex 3D surfaces, such as the hand, with sensors and how to make those sensors differentiate between different kinds of mechanical stimuli.
Researchers at KAIST, a research university in South Korea, have developed a sensitive coating that partially solves these two problems. The investigators are able to spray a special material onto just about any kind of bent surface and to then activate it to make it into a strain sensor. What’s interesting, the sensing material works only to detect strain, ignoring any pressure that may be pushing on it.
Once current is sent through the new coating, the resistance that it experiences changes drastically as the material is stretched. But, when pressure is applied to the same material, the electric resistance barely budges at all.
The “stretchable pressure insensitive strain sensor,” as it is called, will, of course, best work in partnership with its complement, the stretchable strain insensitive pressure sensor. The KAIST team is already working on developing this technology.
Here’s a short video showing the spray-on application process: