Matrix - Water Sensor

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1 介绍

水位检测模块

• 模块Matrix-Water_Sensor是一个简易、性价比较高的水位/水滴识别检测传感器模块，适用于对液位高度的检测，可轻松完成水量到模拟信号的转换。
• 灵敏度可通过电位器调节。

2 特性

• 使用标准的3 PIN接口
• 尺寸为 16x60mm
• PCB尺寸（mm）：16x60

• Pin Description

Pin	Description
S	GPIO
V	Supply Voltage 5V
G	Ground

3 工作原理

• 模块通过一系列暴露的平行导线线迹，利用线迹电极间的电阻与液位高度成比例，测量水量大小从而判断水位。

利用线迹电极间的电阻与雨滴量成比例，测量是否下雨。

4 Applications

The Matrix-Water_Sensor module outputs analog signals which can be converted to digital signals through an ADC converter e.g. the Matrix-Analog_to_Digital_Converter module.
For more details about the Matrix-Analog_to_Digital_Converter module refer to wiki:Matrix_-_Analog_to_Digital_Converter。

4.1 Connect to NanoPi M1

Refer to the following connection diagram to connect the module to the NanoPi M1:

Connection Details:

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

4.2 Connect to NanoPi 2

Refer to the following connection diagram to connect the module to the NanoPi 2:
Matrix-Water_Sensor_nanopi_2

Connection Details:

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

4.3 Connect to NanoPi M2 / NanoPi 2 Fire

Refer to the following connection diagram to connect the module to the NanoPi M2/ NanoPi 2 Fire:

Connection Details:

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

4.4 Connect to NanoPC-T2

Refer to the following connection diagram to connect the module to the NanoPC-T2:
Matrix-Water_Sensor_NanoPC-T2

Connection Details:

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

5 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

6 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