高效的电容式感应设计优化

　　高效的电容式感应设计优化

　　现代点和点击编程软件取代了旧的焊料和希望设计电容传感接口的方法。

　　近年来，在广泛的应用中，人们使用电容式传感接口，从移动电话到计算机、服务终端到家用电子设备，以及医疗设备到工业控制，都有很大幅度的增长。本文将探讨电容传感设计方法的演变，并概述超越猜测和焊接方法的现代调谐过程，使开发人员能够实时校准传感器，而不涉及编码。

　　电容式传感是一种基于触觉的传感方式，它提供了一种替代传统机械按钮和滑块的方法。而感知一个按钮的物理状态，电容传感检测近触屏导电物体的存在和接近传感器的触摸屏。通常，对象是人体的一部分，如手指。为了理解设计过程的演变，理解电容传感的基本知识是很重要的。

　　Fundamental to any capacitive sensing solution are groups of conductors that interact with their surrounding electric fields. The human body itself is full of conductive electrolytes， covered by a poor dielectric： skin. The fact that our bodies， or more specifically our fingers， are conductive is what enables capacitive sensing for human interfaces.

　　If you examine a simple parallel-plate capacitor， you will find two conductors separated by a dielectric layer. The majority of the energy in this capacitor is focused between the two plates; however， some of the energy spills over to the area outside the plates. This spillage creates what is called fringing fields， referring to the overflow electric field lines. A well-designed capacitive sensor function requires controlling the PCB traces to prevent fringing fields spilling over into the active sensing area. As you might guess， a parallel-plate capacitor is not a good choice for our desired sensor pattern.