Researchers from Glasgow University have developed a new type of electronic skin made out of mini-solar cells without dedicated touch sensors. These cells allow the skin to generate its own power and surplus and provides tactile capabilities for touch and proximity sensing.
Similar to regular solar cells, the cells on the s-skin create energy when exposed to a light source. When a cell is shadowed by an approaching object, the intensity of the light and the energy generated reduces. When it drops to zero, it confirms touch with the object. The skin’s proximity mode uses light intensity to determine how far the object is with respect to the cell. The light intensity can be compared in real time and can determine distances after calibration.
To test the concept, the team covered a 3D-printed robotic hand in the solar skin. The results showed an energy surplus of 383.3 mW from the palm of the robotic arm, which is promising. The researchers say that it could generate more than 100 W if it covered the entire body.
“If you look at autonomous, battery-powered robots, putting an electronic skin [that] is consuming energy is a big problem because then it leads to reduced operational time,” notes Ravinder Dahiya of the Bendable Electronics and Sensing Technologies (BEST) Group. “…if you have a skin which generates energy, then…it improves the operational time because you can continue to charge [during operation].”
Because of its material-integrated sensing capabilities, Dahiya envisions numerous uses for the skin. Improving prosthetics is an obvious application. He believes the skin can be used to make prosthetics that are of “optimal weight and size, thus making it easier for prosthetics users.” Additionally, it could reduce time lag seen in brain-computer interfaces by being able to sense when an object is approaching. The skin can even be used for cars, particularly electrical and interactive vehicles. A car covered with the skin could sense an approaching obstacle or person.
Though the new skin shows great promises, there are still challenges to overcome, such as flexibility. The cells in the prototype are made of amorphous silicon, which are not flexible. The team is also working on how to make the solar skin work with different materials.