Difference between revisions of "Matrix - Photoresistor"

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[[Matrix - Photoresistor/zh|查看中文]]
 
[[Matrix - Photoresistor/zh|查看中文]]
  
−
==介绍==
+
==Introduction==
 
[[File:Photoresistor.png|thumb|Photoresistor]]
 
[[File:Photoresistor.png|thumb|Photoresistor]]
−
*Matrix-Photoresistor是一个光敏电阻模块。3-Pin 2.54mm排针接口，V接电源，G接地，S输出的模拟电压信号随着测试环境光照强度减小而增大，你可以把S输出的电压信号通过ADC转换为数字信号，得到与环境光线强度成反比的数字电压信号。
+
*The Matrix-Photoresistor is a photoresistor module. It has a 3 pin 2.54mm spacing pin-header of which V is supply voltage, G is ground and s is output analog signal. The output signal decreases with increasing incident light intensity. Users can convert its output analog signal to a digital signal via ADC conversion.
−
*输出电压范围：0--Vcc
+
*Output Voltage: 0 ~ Vcc
  
−
==特性==
+
==Features==
−
* GPIO 3.3/5V电平
+
* GPIO 3.3/5V
−
* 体积小巧
+
* Small
−
* 2.54mm排针接口
+
* 2.54mm spacing pin-header
−
* PCB尺寸（mm）：8x24
+
* PCB Dimension(mm): 8 x 24
 
[[File:xxx.png | frameless|400px|Photoresistor.PCB]]
 
[[File:xxx.png | frameless|400px|Photoresistor.PCB]]
  
−
* 引脚说明:
+
* Pin Description:
 
{| class="wikitable"
 
{| class="wikitable"
 
|-
 
|-
−
|名称 || 描述
+
|Pin || Description
 
|-
 
|-
−
|S    || 模拟GPIO
+
|S    || Analog GPIO
 
|-
 
|-
−
|V    || 电源5V
+
|V    || Supply Voltage 5V
 
|-
 
|-
−
|G    || 地
+
|G    || Ground
 
|}
 
|}
  
−
==工作原理==
+
==Basic Device Operation==
−
*模块主要器件是一个光敏电阻，光敏电阻的制作材料具有在特定波长的光照射下，其阻值迅速减小的特性。这是由于光照产生的载流子都参与导电，在外加电场的作用下作漂移运动，电子奔向电源的正极，空穴奔向电源的负极，从而使光敏电阻器的阻值迅速下降。在电源激励下，输出端分压减小。
+
*The module has a photoresistor. The resistance of a photoresistor decreases with increasing incident light intensity; in other words, it exhibits photoconductivity.If incident light on a photoresistor exceeds a certain frequency, photons absorbed by the semiconductor give bound electrons enough energy to jump into the conduction band. The resulting free electrons (and their hole partners) conduct electricity, thereby lowering resistance.
  
−
==下载Matrix源码==
+
==Applications==
−
Matrix配件相关的代码是完全开源的，统一由一个仓库进行管理：https://github.com/friendlyarm/matrix.git <br>
+
The Matrix-Photoresistor module outputs analog signals which can be converted to digital signals through an ADC converter e.g. the Matrix-Analog_to_Digital_Converter module.<br>
−
该仓库里不同的分支代表着Matrix配件所支持的不同开发板。<br>
+
For more details about the Matrix-Analog_to_Digital_Converter module refer to wiki: [[Matrix_-_Analog_to_Digital_Converter]].<br>
−
* nanopi分支用于支持NanoPi；
+
−
* nanopi2分支用于支持NanoPi 2；
+
−
* tiny4412分支用于支持Tiny4412；
+
−
* raspberrypi分支用于支持RaspberryPi；
+
  
−
在主机PC上安装git，以Ubuntu14.04为例
+
===Connect to NanoPi M1===
 +
Refer to the following connection diagram to connect the module to the NanoPi M1:<br>
 +
[[File:Matrix-Photoresistor_nanopi_m1.jpg|frameless|600px|Matrix-Photoresistor_nanopi_m1]]
 +
 
 +
Connection Details:
 +
{| class="wikitable"
 +
|-
 +
|Matrix-Photoresistor ||     
 +
|-
 +
|GND    || NanoPi M1 Pin9
 +
|-
 +
|5V    || NanoPi M1 Pin2
 +
|-
 +
|S      || Matrix-Analog_to_Digital_Converter A0
 +
|}
 +
 
 +
===Connect to NanoPi 2===
 +
Refer to the following connection diagram to connect the module to the NanoPi 2:<br>
 +
[[File:Matrix-Photoresistor_nanopi_2.jpg|frameless|600px|Matrix-Photoresistor_nanopi_2]]
 +
 
 +
Connection Details:
 +
{| class="wikitable"
 +
|-
 +
|Matrix-Photoresistor ||     
 +
|-
 +
|GND    || NanoPi 2 Pin9
 +
|-
 +
|5V    || NanoPi 2 Pin2
 +
|-
 +
|S      || Matrix-Analog_to_Digital_Converter A0
 +
|}
 +
 
 +
===Connect to NanoPi M2 / NanoPi 2 Fire===
 +
Refer to the following connection diagram to connect the module to the NanoPi M2/ NanoPi 2 Fire.<br>
 +
[[File:Matrix-Photoresistor_nanopi_m2.jpg|frameless|600px|Matrix-Photoresistor_nanopi_m2]]
 +
 
 +
Connection Details:
 +
{| class="wikitable"
 +
|-
 +
|Matrix-Photoresistor ||     
 +
|-
 +
|GND    || NanoPi M2 Pin9
 +
|-
 +
|5V    || NanoPi M2 Pin2
 +
|-
 +
|S      || Matrix-Analog_to_Digital_Converter A0
 +
|}
 +
 
 +
===Connect to NanoPC-T2===
 +
Refer to the following connection diagram to connect the module to the NanoPC-T2:<br>
 +
[[File:Matrix-Photoresistor_NanoPC-T2.jpg|frameless|600px|Matrix-Photoresistor_NanoPC-T2]]
 +
 
 +
Connection Details:
 +
{| class="wikitable"
 +
|-
 +
|Matrix-Potentiometer ||     
 +
|-
 +
|GND    || NanoPC-T2 USB Host GND
 +
|-
 +
|5V    || NanoPC-T2 USB Host 5V
 +
|-
 +
|S      || Matrix-Analog_to_Digital_Converter A0
 +
|}
 +
 
 +
==Compile & Run Test Program==
 +
Boot your ARM board with Debian and copy the matrix code:
 +
<syntaxhighlight lang="bash">
 +
$ apt-get update && apt-get install git
 +
$ git clone https://github.com/friendlyarm/matrix.git
 +
</syntaxhighlight>
 +
If your cloning is done successfully a "matrix" directory will be generated.
 +
 
 +
Compile and install Matrix:
 +
<syntaxhighlight lang="bash">
 +
$ cd matrix
 +
$ make && make install
 +
</syntaxhighlight>
 +
 
 +
Run test program:
 +
<syntaxhighlight lang="bash">
 +
$ matrix-adc
 +
</syntaxhighlight>
 +
Note: this module is not plug and play therefore before running the module please make sure it is connected to an ARM board.<br>
 +
Here is what you should observe:<br>
 +
<syntaxhighlight lang="bash">
 +
The channel0 value is 2460
 +
</syntaxhighlight>
 +
The resistance of a photoresistor decreases with increasing incident light intensity.
 +
 
 +
==Code Sample==
 +
This Matrix code sample can work with all the ARM boards mentioned in this module's wiki. The name of this code sample is "matrix-3_axis_digital_compass". Here is its source code:
 +
<syntaxhighlight lang="c">
 +
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;
 +
}
 +
</syntaxhighlight>
 +
For more details about this APIs called in this code sample refer to [[Matrix API reference manual]] <br>
 +
 
 +
==Resources==
 +
 
 +
==Update Log==
 +
===June-22-2016===
 +
* Created English wiki
 +
 
 +
<!---
 +
==Download Matrix Source Code==
 +
All the matrix modules' code samples are open source. They are maintained on GitHub: https://github.com/friendlyarm/matrix.git <br>
 +
Each branch in this hub contains the matrix modules' code samples for a board that the matrix modules can work with.<br>
 +
* The nanopi branch contains the matrix modules' code samples for the NanoPi
 +
* The nanopi2 branch contains the matrix modules' code samples for the NanoPi 2
 +
* the tiny4412 branch contains the matrix modules' code samples for the Tiny4412
 +
* the raspberrypi branch contains the matrix modules' code samples for the RaspberryPi
 +
 
 +
Please follow the steps below to get the source code<br>
 +
Install the git utility on a PC running Ubuntu14.04
 
<syntaxhighlight lang="bash">
 
<syntaxhighlight lang="bash">
 
$ sudo apt-get install git
 
$ sudo apt-get install git
 
</syntaxhighlight>
 
</syntaxhighlight>
  
−
克隆Matrix配件代码仓库
+
Clone the matrix code from GitHub
 
<syntaxhighlight lang="bash">
 
<syntaxhighlight lang="bash">
 
$ git clone https://github.com/friendlyarm/matrix.git
 
$ git clone https://github.com/friendlyarm/matrix.git
 
</syntaxhighlight>
 
</syntaxhighlight>
−
克隆完成后会得到一个名为matrix的目录，里面存放着所有Matrix配件的代码。
+
If this is successful a "matrix" directory will be generated, which will contain all the matrix modules' code samples.
  
−
==与NanoPi 2连接使用==
+
==Connect to NanoPi 2==
−
===硬件连接===
+
===Hardware Connection===
−
参考下图连接模块Matrix-Photoresistor和NanoPi 2：<br>
+
Please refer to the following connection diagram to connect the Matrix-Photoresistor to the NanoPi 2:<br>
 
[[File:Matrix-Photoresistor_nanopi_2.jpg|frameless|600px|Matrix-Photoresistor_nanopi_2]]
 
[[File:Matrix-Photoresistor_nanopi_2.jpg|frameless|600px|Matrix-Photoresistor_nanopi_2]]
  
−
连接说明：
+
Connection Details:
 
{| class="wikitable"
 
{| class="wikitable"
 
|-
 
|-
Line 76: Line 209:
 
|S      || Matrix-Analog_to_Digital_Converter A0
 
|S      || Matrix-Analog_to_Digital_Converter A0
 
|}
 
|}
−
光敏电阻输出的是模拟信号，需要使用ADC转换模块Matrix-Analog_to_Digital_Converter将模拟信号转换为数字信号。<br>
+
This module's output signals are analog signals. You can use our Matrix-Analog_to_Digital_Converter to convert them to digital signals.<br>
−
先把模块Matrix-Analog_to_Digital_Converter接在NanoPi 2上，然后将模块Matrix-Photoresistor的S引脚接在ADC转换模块的A0引脚。<br>
+
Please connect the Matrix-Analog_to_Digital_Converter to the NanoPi 2 and then connect Pin S of the Matrix-Photoresistor's pin header to Matrix-Analog_to_Digital_Converter's A0.<br>
−
关于模块Matrix-Analog_to_Digital_Converter可参考wiki：[[Matrix_-_Analog_to_Digital_Converter/zh|Matrix-Analog_to_Digital_Converter]]。<br>
+
For more details about the Matrix-Analog_to_Digital_Converter module please refer to wiki:[[Matrix_-_Analog_to_Digital_Converter]].<br>
  
−
===编译测试程序===
+
===Compile Test Program===
−
进入Matrix代码仓库，切换到nanopi2分支
+
Please login the matrix hub and enter the nanopi2 branch
 
<syntaxhighlight lang="bash">
 
<syntaxhighlight lang="bash">
 
$ cd matrix
 
$ cd matrix
Line 87: Line 220:
 
</syntaxhighlight>
 
</syntaxhighlight>
  
−
编译Matrix配件代码
+
Compile the Matrix code
 
<syntaxhighlight lang="bash">
 
<syntaxhighlight lang="bash">
 
$ make CROSS_COMPILE=arm-linux- clean
 
$ make CROSS_COMPILE=arm-linux- clean
Line 93: Line 226:
 
$ make CROSS_COMPILE=arm-linux- install
 
$ make CROSS_COMPILE=arm-linux- install
 
</syntaxhighlight>
 
</syntaxhighlight>
−
注意：请确保你的主机PC当前使用的交叉编译器为NanoPi 2配套的arm-linux-gcc-4.9.3。<br>
+
Note: please make sure to install the cross compiler "arm-linux-gcc-4.9.3" on your PC, which is used to compile files for the NanoPi 2.<br>
−
编译成功后库文件位于install/lib目录下，而测试程序则位于install/usr/bin目录下，模块Matrix-Photoresistor对应的测试程序为matrix-adc。<br>
+
Generated library files are under the "install/lib" directory. The test program is under the "install/usr/bin" directory. Its test program is "matrix-adc"<br>
−
硬件驱动模块位于modules目录下，对应的驱动源码都包含在在NanoPi 2的Linux内核仓库里：https://github.com/friendlyarm/linux-3.4.y.git <br>
+
The modules are under the "modules" directory. Its driver's source code is in https://github.com/friendlyarm/linux-3.4.y.git <br>
  
−
===运行测试程序===
+
===Run Test Program===
−
将带有Debian系统的SD卡插入一台运行Linux的电脑，可以挂载SD卡上的boot和rootfs分区。<br>
+
Please insert a TF card which is flashed with Debian to a Linux host and mount its boot and rootfs sections.<br>
−
假设rootfs分区的挂载路径为/media/rootfs，执行以下命令将Matrix的硬件驱动、库文件和测试程序拷贝到NanoPi 2的文件系统上。<br>
+
We assume the rootfs is mounted to /media/rootfs then please run the following commands to copy the driver, library and test program to the card.<br>
 
<syntaxhighlight lang="bash">
 
<syntaxhighlight lang="bash">
 
$ cp modules /media/rootfs/ -r
 
$ cp modules /media/rootfs/ -r
Line 106: Line 239:
 
</syntaxhighlight>
 
</syntaxhighlight>
  
−
将SD卡重新插入NanoPi 2，上电启动，在Debian的shell终端中执行以下命令加载硬件驱动。<br>
+
Insert this TF card to your NanoPi 2, power on and run the following commands to load the driver.<br>
 
<syntaxhighlight lang="bash">
 
<syntaxhighlight lang="bash">
 
$ cd /modules
 
$ cd /modules
Line 112: Line 245:
 
</syntaxhighlight>
 
</syntaxhighlight>
  
−
运行模块Matrix-Photoresistor的测试程序。<br>
+
Please run the following command to test the Matrix-Photoresistor module.<br>
 
<syntaxhighlight lang="bash">
 
<syntaxhighlight lang="bash">
 
$ matrix-adc
 
$ matrix-adc
 
</syntaxhighlight>
 
</syntaxhighlight>
−
运行效果如下：<br>
+
Here is what you should expect:<br>
 
[[File:matrix-adc_result.png|frameless||matrix-adc_result]] <br>
 
[[File:matrix-adc_result.png|frameless||matrix-adc_result]] <br>
  
−
===代码展示===
+
===Code Sample===
 
<syntaxhighlight lang="c">
 
<syntaxhighlight lang="c">
 
int main(int argc, char ** argv)
 
int main(int argc, char ** argv)
Line 142: Line 275:
 
}
 
}
 
</syntaxhighlight>
 
</syntaxhighlight>
 +
--->

Latest revision as of 00:46, 22 June 2016

查看中文

1 Introduction

Photoresistor
  • The Matrix-Photoresistor is a photoresistor module. It has a 3 pin 2.54mm spacing pin-header of which V is supply voltage, G is ground and s is output analog signal. The output signal decreases with increasing incident light intensity. Users can convert its output analog signal to a digital signal via ADC conversion.
  • Output Voltage: 0 ~ Vcc

2 Features

  • GPIO 3.3/5V
  • Small
  • 2.54mm spacing pin-header
  • PCB Dimension(mm): 8 x 24

Photoresistor.PCB

  • Pin Description:
Pin Description
S Analog GPIO
V Supply Voltage 5V
G Ground

3 Basic Device Operation

  • The module has a photoresistor. The resistance of a photoresistor decreases with increasing incident light intensity; in other words, it exhibits photoconductivity.If incident light on a photoresistor exceeds a certain frequency, photons absorbed by the semiconductor give bound electrons enough energy to jump into the conduction band. The resulting free electrons (and their hole partners) conduct electricity, thereby lowering resistance.

4 Applications

The Matrix-Photoresistor 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:
Matrix-Photoresistor_nanopi_m1

Connection Details:

Matrix-Photoresistor
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-Photoresistor_nanopi_2

Connection Details:

Matrix-Photoresistor
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.
Matrix-Photoresistor_nanopi_m2

Connection Details:

Matrix-Photoresistor
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-Photoresistor_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 Compile & Run Test Program

Boot your ARM board with Debian and copy the matrix code: 

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

If your cloning is done successfully a "matrix" directory will be generated.

Compile and install Matrix: 

$ cd matrix
$ make && make install

Run test program: 

$ matrix-adc

Note: this module is not plug and play therefore before running the module please make sure it is connected to an ARM board.
Here is what you should observe:

The channel0 value is 2460

The resistance of a photoresistor decreases with increasing incident light intensity.

6 Code Sample

This Matrix code sample can work with all the ARM boards mentioned in this module's wiki. The name of this code sample is "matrix-3_axis_digital_compass". Here is its source code: 

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;
}

For more details about this APIs called in this code sample refer to Matrix API reference manual

7 Resources

8 Update Log

8.1 June-22-2016

  • Created English wiki


Retrieved from "https://wiki.friendlyelec.com/wiki/index.php?title=Matrix_-_Photoresistor&oldid=6195"