智能手机下一代的标配系列3：气压表(Barometer)

智能手机下一代的标配系列3：气压表(Barometer)

(2010-12-01 22:54:59)

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标签： 教育

应用：

气压表也是一种压力传感器，新一代的气压表既可以测量气压和高度，又可以测量温度。所以它既可以做GPS的补充又可以预报天气，可以应用于户外活动和高空作业等，手机配置上这个功能无疑更加智能。

工作原理：

现在气压表只是一个2毫米见方的小芯片，当然不可能是基于托里拆利试验的水银气压计，而是基于piezo－resistive的压电传感器。石英SiO2等晶体,受到压力变化时导致电压的变化，从而电阻也会变化。

通过AD转换，输送到主机，即可知道压力的大小。而温度可以根据PVT的关系计算出来，你懂的。

名词解释 Piezo-resistive

Piezo is derived from the Greek word piezein, “to squeeze.” Piezoelectric materials
produce a voltage when strained. Piezoresistive materials exhibit a change in resistance
when subjected to pressure.

When pressure (stress) is applied to a material it creates a strain or deformation in the
material. In a piezoelectric material this strain creates an electrical potential difference, a voltage. The effect is reversible. When an electric potential is applied across two sides of
a piezoelectric material, it strains. Both effects were discovered by Jacques and Pierre
Curie in 1880-1. The piezoelectric effect is found in materials with a specific electical
crystalline structure. These are known as piezoelectric materials.