Difference between revisions of "Matrix - Soil Moisture Sensor"

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[[Matrix - Soil Moisture Sensor/zh|查看中文]]
 
[[Matrix - Soil Moisture Sensor/zh|查看中文]]
  
==介绍==
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==Introduction==
[[File:Matrix - Soil_Moisture_Sensor.jpg|thumb|土壤湿度检测模块]]
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[[File:Matrix - Soil_Moisture_Sensor.jpg|thumb|Soil Moisture Sensor Module]]
* 模块Matrix-Soil_Moisture_Sensor是一个简易土壤湿度检测传感器模块,适用于对土壤湿度的检测。
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* The Matrix-Soil_Moisture_Sensor is a simple and straightforward-to-use soil moisture detection module.
*选定合适的测量地点,确保钢针不会碰到石块之类坚硬物体,保持土壤原有的松紧程度,握紧传感器体垂直插入土壤,插入时不能前后左右晃动,以确保模块与土壤紧密接触,模块输出与被测土壤湿度成比例的模拟信号。
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* Before plug the module to a target soil make sure the target soil doesn’t contain rocks. Then point the pads perpendicular to the soil, push it in and make the module close contact to the soil and the module will output analog signals which are proportional to the soil’s moisture condition.
*以提高测试准确度,建议在一个测试点附近的小范围内多测试几次求平均值。
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* To improve the test result it is suggested to take the average of multiple test results.
*模块测量数据,会受到盐分,土壤成分,密度等各种因素干扰。
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* The test result can be influenced by various factors: soil density, soil composition and etc.
  
 
==特性==
 
==特性==

Revision as of 00:52, 10 August 2016

查看中文

1 Introduction

Soil Moisture Sensor Module
  • The Matrix-Soil_Moisture_Sensor is a simple and straightforward-to-use soil moisture detection module.
  • Before plug the module to a target soil make sure the target soil doesn’t contain rocks. Then point the pads perpendicular to the soil, push it in and make the module close contact to the soil and the module will output analog signals which are proportional to the soil’s moisture condition.
  • To improve the test result it is suggested to take the average of multiple test results.
  • The test result can be influenced by various factors: soil density, soil composition and etc.

2 特性

  • 使用标准的3 PIN接口
  • 尺寸为 20x60mm
  • PCB尺寸(mm):20x60

Soil_Moisture_Sensor.PCB

  • 引脚说明:
名称 描述
S GPIO
V 电源5V
G

3 工作原理

  • 模块两片测试电极间的阻值与环境的湿度成比例,利用电极间电阻变化测量周围土壤水分湿度。土壤越干燥,输出电压越小。越湿润输出电压越大。模块输出的模拟信号再通过AD转换数字信号信号,即可得到土壤湿度值。
  • 它利用电磁脉冲原理、根据电磁波在介质中传播频率来测量土壤的表观介电常数(ε),从而得到土壤容积含水量(θv)。
  • 使用说明:传感器模块使用的是adc模拟输入输出,这里直接把传感器模块接到PCF8591转换模块上即可检查到土壤湿度值。

3.1 连接NanoPi M1

参考下图连接模块:
Matrix-Soil_Moisture_Sensor_nanopi_m1

连接说明:

Matrix-Soil_Moisture_Sensor
GND NanoPi M1 Pin9
5V NanoPi M1 Pin2
S Matrix-Analog_to_Digital_Converter A0

3.2 连接NanoPi 2

参考下图连接模块:
Matrix-Soil_Moisture_Sensor_nanopi_2

连接说明:

Matrix-Soil_Moisture_Sensor
GND NanoPi 2 Pin9
5V NanoPi 2 Pin2
S Matrix-Analog_to_Digital_Converter A0

3.3 连接NanoPi M2 / NanoPi 2 Fire

NanoPi M2和NanoPi 2 Fire的40 Pin引脚定义是一模一样的,所以它们操作Matrix配件的步骤是一样的,这里仅以NanoPi M2为例。
参考下图连接模块:
Matrix-Soil_Moisture_Sensor_nanopi_m2

连接说明:

Matrix-Soil_Moisture_Sensor
GND NanoPi M2 Pin9
5V NanoPi M2 Pin2
S Matrix-Analog_to_Digital_Converter A0

3.4 连接NanoPi M3

参考下图连接模块:
Matrix-Soil_Moisture_Sensor_nanopi_m3

连接说明:

Matrix-Soil_Moisture_Sensor
GND NanoPi M3 Pin9
5V NanoPi M3 Pin2
S Matrix-Analog_to_Digital_Converter A0

3.5 连接NanoPC-T2

参考下图连接模块:
Matrix-Soil_Moisture_Sensor_NanoPC-T2

连接说明:

Matrix-Potentiometer
GND NanoPC-T2 USB Host GND
5V NanoPC-T2 USB Host 5V
S Matrix-Analog_to_Digital_Converter A0

4 编译运行测试程序

启动开发板并运行Debian系统,进入系统后克隆Matrix代码仓库:

$ apt-get update && apt-get install git
$ git clone https://github.com/friendlyarm/matrix.git

克隆完成后会得到一个名为matrix的目录。

编译并安装Matrix:

$ cd matrix
$ make && make install

运行测试程序:

$ matrix-adc

注意:此模块并不支持热插拔,启动系统前需要确保硬件连接正确。
运行效果如下:

The channel0 value is 2460

5 代码说明

所有的开发板都共用一套Matrix代码,本模块的测试示例代码为matrix-analog_to_digital_converter,内容如下:

int main(int argc, char ** argv)
{
    int i = 0;
    int value = 0;
    int channel = 0;
 
    if (boardInit() < 0) {
        printf("Fail to init board\n");
        return -1;
    }
 
    if (argc == 2)
        channel = atoi(argv[1]);
    system("modprobe "DRIVER_MODULE);
    signal(SIGINT, intHandler);
    for (i=0; i<ADC_READ_TIMES; i++) {
        if (pcf8591Read(channel, &value) != -1) {
            printf("The channel%d value is %d\n", channel, value);
        } else {
            printf("Fail to get channel%d value\n", channel);
        }
    }
    system("rmmod "DRIVER_MODULE);
 
    return 0;
}

API说明参考维基:Matrix API reference manual

6 相关资料