Researchers from the New York University have developed a new multi-touch display which is cheaper and more flexible than conventional touchscreens. iPhone-like screens can be operated with only one finger, while Microsoft’s touch-surface is expensive and rigid, but this new multitouch interface is flexible, meaning that it can be sized to fit small devices, and it can also be designed to fit a wall. The New York University researchers have called it the Inexpensive Multi-Touch Pressure Acquisition Device, and they will unveil it at the Computer Human Interaction show in Boston next week.
You might be wondering what’s so special about the IMPAD – well, iPhone-like touchscreens measure capacitance changes when an object or finger touches the display; other touch interfaces like surface screens are based on cameras to check the position of the objects or fingers; other displays like Perceptive Pixel are also based on cameras, but they capture information using infrared light and pressure, and they are not practical for use with small devices. On the other hand, IMPAD consists of few layers of materials and it measures the change of electrical resistance when it comes in contact with a finger or an object.
“One of the problems that’s been endemic to multitouch sensors is . . . you’re either touching it or not touching it. A significant amount of potentially useful information is thrown away because the sensor isn’t capturing the subtleties,” said Ken Perlin, Professor of Media Research at the New York University.
Another advantage of IMPAD is that it measures the pressure that a person applies to the touchpad meaning that it can measure how hard you press it and this opens up a broad range of applications – the device can be used to control a piano keyboard or other musical instruments, or you can use it for virtual painting or sculpting.
Aforementioned, I said that IMPAD consists of few materials, and according to Ilya Rosenberg, graduate researcher and co-author at the study, the device is based on two plastic sheets which measure 8 to 10 inches, and each include parallel lines of electrodes. The lines of electrodes are spaced a quarter-inch apart, and you will notice that they form a grid, and each intersection is actually a pressure sensor. The key to the IMPAD device is the FSR (force sensitive resistor) ink which “features” tiny bumps on its surface, and which was previously used on musical instruments.
How does the FSK ink work? Well, when you press an object coated with the ink, the microscopic bumps move along and touch each other while conducting electricity.
“The harder you press, the more it conducts,” said Rosenberg.
In order to make it perfect, the NYU team of researchers were looking to measure the exact placement of an object touching the IMPAD, but they needed too many sensors and expensive wiring for that. The goal was to measure to a resolution of 100 dots per square inch, and instead of using something expensive, they developed a complex algorithm that calculates the input at each intersection, and inserts the exact position of a finger or object, no matter how small it is.
The algorithm also allows the touch interface to realize when you press with two fingers – it collects information, sends it to a computer which measures the intensity and the exact placement of the objects, and according to Rosenberg, the computer collects information from the multi-touch pad 50 to 200 times per second, but the researchers are still looking to improve the technology.
“The pad gives you an animated pressure picture but has only 20 connectors or so coming out of it. This sounds like it’s not a big deal, but it makes it feasible to use it on very small mobile devices such as our nanoTouch,” said Patrick Baudisch, a researcher at Microsoft which collaborates with the NYU researchers.
For the moment, the researchers would like to commercialize this technology, while in the future the NYU team predicts that IMPAD will replace conventional touchscreen in cellphones and other touch-based devices. The multi-touch interface could be used as a skin for robots giving them the possibility to detect and feel touch. Also the technology could be used in construction industry as it could measure stress on structures and buildings. Only the future will tell if this technology will have enourmous implications in various topics. Until then stay tuned, and we will come with more information next week from Boston.