Phone Borneo

Resistive and the LCD display is difficult to fully and accurately all the points with, so addition to calibration of precision mechanical assembly technologies, the use of software program should also be calibrated before. This article describes the calibration process 1st decide the source of error, and then export the three selected points, touch-screen calibration matrix, and use the computer software method to implement the corresponding relation among points of calibration. To master this technique for lowering the cost of embedded systems is crucial.
Figure 1 shows a resistive touch-screen cross-section, its structure is incredibly rather simple, from leading to bottom the relative placement of two pieces of glass composition, the inner surface of glass coated with a thin layer of conductive material, and applied some little glass beads across the surface of the conductive open. When the finger or stylus press the glass surface, the upper make contact with with the lower glass bending glass. The structure of glass beads determines the distance between the touch screen sensitivity. The even more glass beads placed close to every single other, the sensitivity the smaller the greater the pressure vital to make trustworthy make contact with with two layers of glass.

Touch screen calibration method - mxpopstar - The Frozen Throne
Figure 2 shows the equivalent circuit of touch-screen. Through a touch screen controller (AD converter) to the power of the positive and negative added to a conductive layer of the glass at each ends, and the other a piece of glass on the conductive layer is to play the function of a potentiometer cursor. On glass of distinct touch points, conducting the situation is completely different, digital converter will be recorded in the distinct test voltage value, then controller will be recorded in the voltage value converted into a two-dimensional coordinates: X-axis coordinates and Y coordinates of .