查看“Micro:bit系列教程14：Moisture Sensor检测土壤湿度”的源代码



本章将介绍Moisture
Sensor对土壤湿度的检测。


<h1 style="line-height:150%"><span lang="EN-US" style="font-size:15.0pt;
line-height:150%;font-family:黑体">1.<span style="font-size:15.0pt;
line-height:150%;font-family:黑体">基本介绍

</h1>

<span lang="EN-US" style="font-size:
15.0pt;line-height:150%;font-family:黑体">  Moisture
Sensor模块主要是利用三极管的电流放大原理。当土壤中的水分使三极管的基极与电源正极导通的时候，在三极管的基极和发射极之间就会产生一定大小的电流，此时在三极管的集电极和发射极之间就会产生一个一定放大倍数的电流，该电流经过发射极的电阻产生电压供AD转换器采集。


<h1 style="line-height:150%"><span lang="EN-US" style="font-size:15.0pt;
line-height:150%;font-family:黑体">2.<span style="font-size:15.0pt;
line-height:150%;font-family:黑体">硬件连接

</h1>

    <span style="font-size:12.0pt;
line-height:150%;font-family:宋体">在硬件连接上，采用Micro:bit的P0引脚来获取Moisture Sensor模拟信号的大小，并进行AD转换，从而得到数字信号。


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Micro:bit


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Sound Sensor


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VCC


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VCC


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GND


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GND


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  padding:0cm 5.4pt 0cm 5.4pt" width="277">

P0


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AOUT


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<span style="font-size:12.0pt;
line-height:150%;font-family:宋体">具体硬件连接如下图所示：




[[File:141024k5p4w454z24j2wjn.png]]

<h1 style="line-height:150%"><span lang="EN-US" style="font-size:15.0pt;
line-height:150%;font-family:黑体">3.<span style="font-size:15.0pt;
line-height:150%;font-family:黑体">软件设计

</h1>

<span lang="EN-US" style="font-family:
宋体">  <span style="font-size:12.0pt;
line-height:150%;font-family:宋体">打开makecode，添加软件包，输入以下链接：




<span style="font-size:12.0pt;
line-height:150%;font-family:宋体">https://github.com/waveshare/CourseKit
<span lang="EN-US" style="font-size:12.0pt;line-height:150%;
font-family:宋体">



<span style="font-size:12.0pt;
line-height:150%;font-family:宋体">添加软件包成功后，采用积木块编写以下程序：




[[File:141025l8xdkq3qvq8qu6vx.png]]


<span style="font-size:12.0pt;
line-height:150%;font-family:宋体">下载，点击显示数据(设备)，可观测Micro:bit读取Moisture
Sensor模块的ADC值及转换后的电压(mv):




[[File:141026e83y0fgbcvt2s379.png]]


<span style="font-size:12.0pt;
line-height:150%;font-family:宋体">将Moisture Sensor插入土壤中，并往土壤中加水，随着土壤湿度的增加，Micro:bit读取的ADC值将增大。