Multitouch pads
March 31st, 2009 by rbanks
A Better, Cheaper Multitouch Interface
“It consists of two plastic sheets, about 8 inches by 10 inches, each with parallel lines of electrodes, spaced a quarter inch apart. The sheets are arranged so that the electrodes cross, creating a grid; each intersection is essentially a pressure sensor. Crucially, both sheets are covered with a layer of force sensitive resistor (FSR) ink, a type of ink that has microscopic bumps on its surface. When something coated in the ink is pressed, the bumps move together and touch, conducting electricity. “The harder you press, the more it conducts,” says Rosenberg.” 
Technology Review
