How do touch-screen monitors know where you e touching?
Touch-screen monitors have become more and more commonplace as their price has steadily dropped over the past decade. There are three basic systems that are used to recognize a person’s touch: • Resistive • Capacitive • Surface acoustic wave The resistive system consists of a normal glass panel that is covered with a conductive and a resistive metallic layer. These two layers are held apart by spacers, and a scratch-resistant layer is placed on top of the whole setup. An electrical current runs through the two layers while the monitor is operational. When a user touches the screen, the two layers make contact in that exact spot. The change in the electrical field is noted and the coordinates of the point of contact are calculated by the computer. Once the coordinates are known, a special driver translates the touch into something that the operating system can understand, much as a computer mouse driver translates a mouse’s move
