Touch screen or touch activated technology has been around for a few decades now, but only recently have prices dropped and the technology been (somewhat) perfected. As an input device touch screens offer a more natural interaction that humans are used to, which offers a great advantage for businesses selling to the general public over traditional keyboards and mouses.
This article will look at how to interface to a 4-wire resistive touch screen and find out the X and Y coordinates of the current point being touched. A minimal number of parts will be used to simplify the system hardware, and to focus more on the theory of how it works.
Simple Touch Screen Interface - [Link]