Four-wire Resistive Touch Screen Test System

Because of its cost-effective, easy-to-use and low demands on the environment and other factors, at present, the four-wire resistive touch screen has accounted for the vast majority of the use of share. It has quickly response speed, sturdiness and durability, and space-saving, easy to exchange and many other advantages. So, it has become the most simple, convenient and natural way a human-computer interaction and has been widely used in our country. Therefore, it is necessary to study the principles of the four-wire resistive touch screen and develop highly efficient, accurate, stable, easy-to-use test equipment.Based on analysis of the principle of four-wire resistive touch screen ,the dissertation designs a sophisticated test system for the screen to meet the requirements of high precision of testing, zero voltage and pole voltage of touch screen drifting. By the support of mechanical components and combined with data acquisition circuit, stepping motor, pressure sensor and self-developed testing software, the system achieves test function. It reached a very high test accuracy and test efficiency.The development of the system monitoring and control software makes full use of MFC library, data buffer pool technology and database technology. VS2005 is used as its development platform and VC++ as development language. The system achieves peer to peer communication for upper and lower computer, real time response of the control order with displaying testing curve, state of lower computer and effective management of testing parameters and date of testing results. What's more, it has friendly user interface.The noise in the process of testing is the key of the accuracy and stability reasons of testing. The dissertation systematic analyzes a variety of noise sources in testing process. It includes the noise caused by the abnormal distribution of resistor, the overall migration test data, the noise caused by dust or scratches. Then, through the noise characteristics of the different analysis, using four-point voltage to correct algorithm, correcting algorithm, the weighted five times to deal with filtering algorithms to improve the test process and test the accuracy of anti-interference ability. The system automatically detect effective border and calibrate the difference of every screen in the testing process. The system can meet the needs well of a variety of tests at the scene of the application.