构建移动多传感器系统由触摸屏为主

　　构建移动多传感器系统由触摸屏为主

　　移动设备似乎都有触摸屏显示器，也经常有许多其他传感器。理解底层技术可以帮助您评估这些设计中不可避免的权衡。

　　现代游戏、医疗和移动设备主要由集中显示为主要用户界面的触摸显示器所主导。然而，这些产品大多是可以从多种类型的传感器中受益的系统，用于确定位置、运动和其他环境条件。使用模型和反应决定的触摸界面，可以使用的类型。可利用的传感器类型、开发和应用支持、产品实现问题以及分级可用性将得到解决。

　　触摸传感器

　　有多个触摸传感器的接口和技术可。几个有针对性的大面积应用或需要线式电力执行。移动空间是这些接口的新的“量”的地区。移动空间的指南包括17英寸以下的显示器、电池操作、断电模式、毫秒响应时间和设备上的单个用户。这些要求将主流触摸技术缩小到三种类型：电阻式、投射式电容式和表面电容式。这三个技术概述如表1所示。

　　Resistive touch is one of the oldest and simplest technologies. The touch screen is based on a flexible conductive layer （generally coated with Indium-Tin-Oxide ［ITO］） that is spaced above another ITO conductive layer. When the top layer is flexed or depressed， it makes contact with the bottom layer and then creates a localized voltage change. The location of the voltage change is sensed， and that determines the position of the touch， as shown in Figure 1. This is a high accuracy technology， as the flex of the top layer can be from a large area object such as a gloved finger， or a very small area such as the end of a stylus. The technology also allows for weather and dust/foreign material resistance by allowing the edges of the top layer to be sealed. Digi-Key carries resistive touch control ICs from ten suppliers - Analog Devices， Inc.， Atmel， Integrated Device Technology （IDT）， Maxim， Microchip Technology， National Semiconductor， ROHM Semiconductor， Semtech， STMicroelectronics， and Texas Instruments （TI）。 The resistive touch ICs for the display systems， including those used by cell phones， are all supported by development systems featuring access to all stages of the data pipeline. Development systems such as the EVAL-AD7877EBZ-ND from Analog Devices， Inc. include software， cables， a touch sensor， control electronics， and a display. These systems allow for the application development and real-time test of the sensors. The high speed of resistive touch systems， in addition to the ability to have sealed displays， continued operation when moisture or fluid is on the screen， and a firm non-accidental touch， makes resistive touch the preferred technology for industrial control and medical electronics.