The method works because the electrical field polarises the electric charge on water molecules in the air around the icy tip and then draws them in electrostatically.
Because the technique uses off-the-shelf wireless transceivers similar to those used in home computer networks, "the cost of this system will be cheaper than existing methods of monitoring breathing, " says Neal Patwari, senior author of a study of the new method and an assistant professor of electrical engineering.
Their method was based on the observation that electrical currents will be induced in a conductor (such as water) when it is faced with a magnetic field that varies over time.
His device will use Electrical Impedance Tomography (EIT), a medical imaging method in which images are produced quickly using electrodes placed around the body, to detect changes or abnormalities in the brain.
Rather than look for physical ridges, the scientists' method sweeps through AC frequencies to find the exact electrical impedances of fingertips in contact with the screen.
You see, it's been difficult for OLED builders to secure enough electrical conductivity of ITO in a low-temperature process, and this new methodology is perfectly suited for the coating method (which makes it ripe for printing).