Two-finger input with a standard touch screen

Most current implementations of multi-touch screens are still too expensive or too bulky for widespread adoption. To improve this situation, this work describes the electronics and software needed to collect more data than one pair of coordinates from a standard 4-wire touch screen. With this system, one can measure the pressure of a single touch and approximately sense the coordinates of two touches occurring simultaneously. Naturally, the system cannot offer the accuracy and versatility of full multi-touch screens. Nonetheless, several example applications ranging from painting to zooming demonstrate a broad spectrum of use.