Difference between revisions of "Matrix - Temperature Sensor"

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[[File:TemperatureSensor01.png|thumb|Temperature Sensor]]
 
[[File:TemperatureSensor01.png|thumb|Temperature Sensor]]
 
* The matrix-temperature_sensor module is used to measure temperature.
 
* The matrix-temperature_sensor module is used to measure temperature.
−
* 搭载了一颗非常流行的TO-92封装的DS18B20芯片。从DS18B20读出的信息或写入DS18B20的信息仅需要一根口线（单线接口）读写,温度变换功率来源于数据总线，总线本身也可以向所挂接的DS18B20供电。DSl820的电源可以由数据线本身提供而不需要外部电源，因为每一个DSl820在出厂时已经给定了唯一的序列号。
+
* We utilitze the DS18B20 chip with the To-92 package in this module. Its unique 1-wire interface requires only 1 port pin for reading/writing. Power for reading, writing, and performing temperature conversions can be derived from the data line itself with no need for an external power source. The DS18B20 can be powered from its data line. Each DS18B20 is assigned a unique ID.
−
* 测量范围是-55摄氏度到+125摄氏度，可选9-bit或12-bit，在-10摄氏度到+85摄氏度时可以精确到0.5度，采用一线协议通讯。我们把DS18B20的3个针脚全部引出，V对应电源引脚，G对应地引脚，S对应数据引脚。
+
* Its temperature range is -55 degree Celsius to +125 degree Celsius. The thermometer resolution is programmable from 9 to 12 bits. When the measured temperature is between -10 degree Celsius to +85 degree Celsius the accuracy can be at 0.5 degree. Among all three DS18B20 pins V is power, G is ground and S is data.
  
 +
==Features==
 +
* -55 degree Celsius to +125 degree Celsius
 +
* One wire interface for communication
 +
* Tiny, easy to be deployed in various situations
 +
* 2.54mm spacing pin
 +
* PCB dimension(mm): 8 X 24
 +
[[File:temppcb.png|frameless|400px|Temperature Sensor PCB]]
  
−
We utilitze the DS18B20 in this module. The DS18B20 can be powered from its data line. Each DS18B20 is assigned a unique ID. Its temperature range is -55 degree Celsius to +125 degree Celsius. The thermometer resolution is programmable from 9 to 12 bits. When the measured temperature is between -10 degree Celsius to +85 degree Celsius the accuracy can be at 0.5 degree. It uses the unique 1-wire interface which requires only one port pin for communication. Among all three DS18B20 pins V is power, G is ground and S is data.
 
  
 +
*Pin Description:
 +
{| class="wikitable"
 +
|-
 +
|Pin || Description
 +
|-
 +
|S    || GPIO
 +
|-
 +
|V    || Supply Voltage 5V
 +
|-
 +
|G    || Ground
 +
|}
 +
 +
==Basic Device Operation==
 +
The core functionality of the DS18B20 is its direct-to-digital temperature sensor. The resolution of the DS18B20 is configurable (9, 10, 11, or 12 bits), with 12-bit readings the factory default state. This
 +
equates to a temperature resolution of 0.5°C, 0.25°C, 0.125°C, or 0.0625°C. Following the issuance of the Convert T [44h] command, a temperature conversion is performed and the thermal data is stored in the scratchpad memory in a 16-bit, sign-extended two’s complement format. The temperature information can be retrieved over the 1-Wire interface by issuing a Read Scratchpad [BEh] command once the conversion has been performed. The data is transferred over the 1-Wire bus, LSB first. The MSB of the temperature register contains the “sign” (S) bit, denoting whether the temperature is positive or negative.
  
−
==特性==
+
==Applications==
−
* -55摄氏度到+125摄氏度
+
===Connect to NanoPi M1===
−
* 一线协议
+
Refer to the following connection diagram to connect the module to the NanoPi M1:<br>
−
* 体积小巧， 带固定孔，方便嵌入到外壳
+
[[File:Matrix-Temperature_Sensor_nanopi_m1.jpg|frameless|600px|Matrix-Temperature_Sensor_nanopi_m1]]
−
* 2.54mm排针接口，接线方便，通用性强
+
−
* PCB尺寸（mm）:8X24
+
−
[[File:temppcb.png|frameless|400px|温度传感器PCB]]
+
  
−
*引脚说明:  
+
Connection Details:
 
{| class="wikitable"
 
{| class="wikitable"
 
|-
 
|-
−
|名称 || 描述
+
|Matrix-Temperature_Sensor || NanoPi M1
 +
|-
 +
|S    || Pin7
 +
|-
 +
|V    || Pin4
 
|-  
 
|-  
−
|S   || GPIO
+
|G   || Pin6
 +
|}
 +
 
 +
===Connect to NanoPi 2===
 +
Refer to the following connection diagram to connect the module to the NanoPi 2:<br>
 +
[[File:Matrix-Temperature_Sensor_nanopi_2.jpg|frameless|600px|Matrix-Temperature_Sensor_nanopi_2]]
 +
 
 +
Connection Details:
 +
{| class="wikitable"
 
|-
 
|-
−
|V    || 电源5V
+
|Matrix-Temperature_Sensor || NanoPi 2
 
|-
 
|-
−
|G    || 地
+
|S    || Pin7
 +
|-
 +
|V    || Pin4
 +
|-
 +
|G    || Pin6
 
|}
 
|}
  
−
==工作原理==
+
===Connect to NanoPi M2 / NanoPi 2 Fire===
−
DS18B20低温度系数晶振的振荡频率受温度影响很小，用于产生固定频率的脉冲信号送给计数器1。高温度系数晶振随温度变化其振荡率明显改变，所产生的信号作为计数器2的脉冲输入。计数器1和温度寄存器被预置在-55℃所对应的一个基数值。计数器1对低温度系数晶振产生的脉冲信号进行减法计数，当计数器1的预置值减到0时，温度寄存器的值将加1，计数器1的预置将重新被装入，计数器1重新开始对低温度系数晶振产生的脉冲信号进行计数，如此循环直到计数器2计数到0时，停止温度寄存器值的累加，此时温度寄存器中的数值即为所测温度。
+
Refer to the following connection diagram to connect the module to the NanoPi M2/ NanoPi 2 Fire:<br>
 +
[[File:Matrix-Temperature_Sensor_nanopi_m2.jpg|frameless|600px|Matrix-Temperature_Sensor_nanopi_m2]]
  
−
==下载Matrix源码==
+
Connection Details:
−
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：git://github.com/friendlyarm/matrix.git <br>
+
{| class="wikitable"
−
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>
+
|-
−
* nanopi分支包含了Matrix对NanoPi的支持；
+
|Matrix-Temperature_Sensor || NanoPi M2
−
* tiny4412分支包含了Matrix对Tiny4412的支持；
+
|-
−
* raspberrypi分支包含了Matrix对RaspberryPi的支持；
+
|S    || Pin7
 +
|-
 +
|V    || Pin4
 +
|-
 +
|G    || Pin6
 +
|}
  
−
在主机PC上安装git，以Ubuntu14.04为例
+
===Connect to NanoPC-T2===
 +
Refer to the following connection diagram to connect the module to the NanoPC-T2:<br>
 +
[[File:Matrix-Temperature_Sensor_NanoPC-T2.jpg|frameless|600px|Matrix-Temperature_Sensor_NanoPC-T2]]
 +
 
 +
Connection Details:
 +
{| class="wikitable"
 +
|-
 +
|Matrix-Temperature_Sensor || NanoPC-T2
 +
|-
 +
|S    || Pin15
 +
|-
 +
|V    || Pin29
 +
|-
 +
|G    || Pin30
 +
|}
 +
 
 +
==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-temp_sensor
 +
</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 temperature is 27.312 C
 +
</syntaxhighlight>
 +
The module successfully read the environment's temperature.
 +
 
 +
==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-temperature_sensor". Here is its source code:
 +
<syntaxhighlight lang="c">
 +
int main(int argc, char ** argv)
 +
{
 +
    char temperature[BUF_SIZE], modStr[BUF_SIZE];
 +
    int board;
 +
    int pin=GPIO_PIN(7);
 +
   
 +
    if ((board = boardInit()) < 0) {
 +
        printf("Fail to init board\n");
 +
        return -1;
 +
    }
 +
    if (board == BOARD_NANOPI_T2)
 +
        pin = GPIO_PIN(15);
 +
   
 +
    if (argc == 2)
 +
        pin = atoi(argv[1]);
 +
    sprintf(modStr, "modprobe %s gpio=%d", TEMP_GPIO_DRIVER_MODULE, pintoGPIO(pin));
 +
    printf("%s\n", modStr);
 +
    system(modStr);
 +
    system("modprobe "TEMP_DRIVER_MODULE);
 +
    sleep(1);
 +
    memset(temperature, 0, BUF_SIZE);
 +
    if (ds18b20Read(temperature) > 0) {
 +
        printf("The temperature is %.3f C\n", atoi(temperature)/1000.0);
 +
    } else {
 +
        printf("Fail to get temperature\n");       
 +
    }
 +
    system("rmmod "TEMP_GPIO_DRIVER_MODULE);
 +
    system("rmmod "TEMP_DRIVER_MODULE);
 +
    return 0;
 +
}
 +
</syntaxhighlight>
 +
For more details about this APIs called in this code sample refer to [[Matrix API reference manual]] <br>
 +
 
 +
<!---
 +
==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 nanopi 2 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 git://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matrix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.
 +
 
 +
 
 +
==Connect to NanoPi 2==
 +
===Hardware Connection===
 +
Please refer to the following connection diagram to connect the Matrix-Temperature_Sensor to the NanoPi 2:<br>
 +
[[File:Matrix-Temperature_Sensor_nanopi_2.jpg|frameless|600px|Matrix-Temperature_Sensor_nanopi_2]]
 +
 
 +
Connection Details:
 +
{| class="wikitable"
 +
|-
 +
|Matrix-Temperature Sensor || NanoPi 2
 +
|-
 +
|S  || Pin7
 +
|-
 +
|V  || Pin4
 +
|-
 +
|G  || Pin6
 +
|}
  
−
==与NanoPi连接使用==
+
===Compile Test Program===
−
===准备工作===
+
Please login the matrix hub and enter the nanopi2 branch
−
在NanoPi上运行Debian系统，然后在主机PC上安装并使用相应的编译器。参考wiki：[[NanoPi/zh|NanoPi]] <br>
+
<syntaxhighlight lang="bash">
−
注意：必须使用nanopi-v4.1.y-matrix分支编译出来的内核。<br>
+
$ cd matrix
−
下载NanoPi内核源代码并编译
+
$ git checkout nanopi2
 +
</syntaxhighlight>
 +
 
 +
Compile the matrix code
 +
<syntaxhighlight lang="bash">
 +
$ make CROSS_COMPILE=arm-linux- clean
 +
$ make CROSS_COMPILE=arm-linux-
 +
$ make CROSS_COMPILE=arm-linux- install
 +
</syntaxhighlight>
 +
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>
 +
Generated library files are under the "install/lib" directory. The test program is under the "install/usr/bin" directory.<br>
 +
The modules are under the "modules" directory. The driver's source code is in github: https://github.com/friendlyarm/linux-3.4.y.git <br>
 +
 
 +
===Run Test Program===
 +
Please insert a TF card which is flashed with Debian to a Linux host and mount its boot and rootfs sections.<br>
 +
We assume the rootfs is mounted to /media/rootfs then please run the following commands to copy the module, library and test program to the card.<br>
 +
<syntaxhighlight lang="bash">
 +
$ cp modules /media/rootfs/ -r
 +
$ cp install/lib/* /media/rootfs/lib/ -d
 +
$ cp install/usr/bin/* /media/rootfs/usr/bin/
 +
</syntaxhighlight>
 +
 
 +
Insert this TF card to your NanoPi 2, power on and run the following commands to load the driver.<br>
 +
<syntaxhighlight lang="bash">
 +
$ cd /modules
 +
$ insmod w1-gpio.ko
 +
</syntaxhighlight>
 +
 
 +
Start the matrix-temp_sensor program.<br>
 +
<syntaxhighlight lang="bash">
 +
$ matrix-temp_sensor
 +
</syntaxhighlight>
 +
 
 +
Here is what you expect to observe:<br>
 +
[[File:matrix-temperature_sensor_result.png|frameless|600px|matrix-temperature_sensor_result]]
 +
 
 +
===Code Sample===
 +
<syntaxhighlight lang="c">
 +
int main(int argc, char ** argv)
 +
{
 +
    char temperature[BUF_SIZE];
 +
    memset(temperature, 0, BUF_SIZE);
 +
    if (ds18b20Read(temperature) > 0) {
 +
        printf("Temperature = %.3f C\n", atoi(temperature)/1000.0);
 +
    } else {
 +
        printf("Fail to get temperature\n");       
 +
    }
 +
    return 0;
 +
}
 +
</syntaxhighlight>
 +
 
 +
==Connect to NanoPi==
 +
===Preparations===
 +
Please install a Debian on a NanoPi and an appropriate cross compiler on a PC. Please refer to wiki: [[NanoPi/zh|NanoPi]] <br>
 +
Compile a NanoPi kernel. Note: please use the kernel's source code from the nanopi-v4.1.y-matrix branch<br>
 
<syntaxhighlight lang="bash">
 
<syntaxhighlight lang="bash">
 
$ git clone https://github.com/friendlyarm/linux-4.x.y.git
 
$ git clone https://github.com/friendlyarm/linux-4.x.y.git
Line 66: Line 265:
 
</syntaxhighlight>
 
</syntaxhighlight>
  
−
===硬件连接===
+
===Hardware Connection===
−
参考下图连接模块Matrix-Temperature_Sensor和NanoPi <br>
+
Please refer to the following connection diagram to connect the Matrix-Temperature_Sensor module to the NanoPi <br>
 
[[File:matrix-temperature_sensor_nanopi.jpg|frameless|600px|matrix-temperature_sensor_nanopi]]
 
[[File:matrix-temperature_sensor_nanopi.jpg|frameless|600px|matrix-temperature_sensor_nanopi]]
  
−
连接说明：
+
Connection Details:
 
{| class="wikitable"
 
{| class="wikitable"
 
|-
 
|-
Line 82: Line 281:
 
|}
 
|}
  
−
===编译测试程序===
+
===Compile Test Program===
−
进入Matrix代码仓库，切换到nanopi分支
+
Please login the matrix hub and enter the nanopi branch
 
<syntaxhighlight lang="bash">
 
<syntaxhighlight lang="bash">
 
$ cd matrix
 
$ cd matrix
Line 89: Line 288:
 
</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 95: Line 294:
 
$ 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-Debian配套的arm-linux-gcc-4.4.3。<br>
+
Note: please make sure to install the cross compiler "arm-linux-gcc-4.4.3" on your PC, which is used to compile files for the NanoPi-Debian.<br>
−
编译出来的库文件位于install/lib目录下，而测试程序则位于install/usr/bin目录下，模块Matrix-Temperature_Sensor对应的测试程序为matrix-temperature_sensor。<br>
+
Generated library files are under the "install/lib" directory. Applications are under the "install/usr/bin" directory. The test program for the "Matrix-Temperature_Sensor" module is "matrix-temperature_sensor".<br>
  
−
===运行测试程序===
+
===Run Test Program===
−
拷贝库文件和测试程序到NanoPi的文件系统上
+
Please copy the library files and test program to the NanoPi
 
<syntaxhighlight lang="bash">
 
<syntaxhighlight lang="bash">
 
$ cp install/usr/bin/* nanopi_rootfs/usr/bin/
 
$ cp install/usr/bin/* nanopi_rootfs/usr/bin/
Line 105: Line 304:
 
</syntaxhighlight>
 
</syntaxhighlight>
  
−
然后启动NanoPi，在Debian的shell终端中执行如下命令运行模块Matrix-Temperature_Sensor的测试程序 <br>
+
Power on the NanoPi and run the following command in Debian's terminal <br>
−
注意：此模块并不支持热插拔，启动系统前需要确保硬件正常连接。
+
Note: this module is not plug and play therefore before running the module please make sure it is connected to a NanoPi.
 
<syntaxhighlight lang="bash">
 
<syntaxhighlight lang="bash">
 
$ matrix-temperature_sensor
 
$ matrix-temperature_sensor
 
</syntaxhighlight>
 
</syntaxhighlight>
  
−
===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 141: Line 340:
 
</syntaxhighlight>
 
</syntaxhighlight>
  
−
==与Tiny4412连接使用==
+
==Connect to Tiny4412==
−
===准备工作===
+
===Preparations===
−
参考Tiny4412光盘里的《友善之臂Ubuntu使用手册》，在Tiny4412上运行UbuntuCore系统，然后在主机PC上安装并使用相应的编译器。<br>
+
Please refer to the Tiny4412's user's manual to install a UbuntuCore on the Tiny4412 and install an appropriate cross compiler on a PC.<br>
−
注意：只能使用Tiny4412SDK-1506的底板。
+
Note: only the Tiny4412SDK-1506 carrier board can work with this module.
  
−
===硬件连接===
+
===Hardware Connection===
−
参考下图连接模块Matrix-Temperature_Sensor和Tiny4412 <br>
+
Please refer to the following diagram to connect the Matrix-Temperature_Sensor to the Tiny4412 <br>
 
[[File:matrix-temperature_sensor_tiny4412.jpg|frameless|600px|matrix-temperature_sensor_tiny4412]]
 
[[File:matrix-temperature_sensor_tiny4412.jpg|frameless|600px|matrix-temperature_sensor_tiny4412]]
  
−
连接说明：
+
Connection Details:
 
{| class="wikitable"
 
{| class="wikitable"
 
|-
 
|-
Line 162: Line 361:
 
|}
 
|}
  
−
===编译测试程序===
+
===Compile Test Program===
−
进入Matrix代码仓库，切换到tiny4412分支
+
Please login the Matrix hub and enter the matrix-tiny4412 branch
 
<syntaxhighlight lang="bash">
 
<syntaxhighlight lang="bash">
 
$ cd matrix
 
$ cd matrix
Line 169: Line 368:
 
</syntaxhighlight>
 
</syntaxhighlight>
  
−
编译Matrix配件代码
+
Compile the matrix code
 
<syntaxhighlight lang="bash">
 
<syntaxhighlight lang="bash">
 
$ make CROSS_COMPILE=arm-linux-gnueabihf- clean
 
$ make CROSS_COMPILE=arm-linux-gnueabihf- clean
Line 175: Line 374:
 
$ make CROSS_COMPILE=arm-linux-gnueabihf- install
 
$ make CROSS_COMPILE=arm-linux-gnueabihf- install
 
</syntaxhighlight>
 
</syntaxhighlight>
−
注意：请确保你的主机PC当前使用的交叉编译器为Tiny4412-UbuntuCore配套的arm-linux-gnueabihf-gcc-4.7.3。<br>
+
Note: please make sure to install the cross compiler "arm-linux-gnueabihf-gcc-4.7.3" on your PC, which is used to compile files for the Tiny4412-UbuntuCore.<br>
−
编译出来的库文件位于install/lib目录下，而测试程序则位于install/usr/bin目录下，模块Matrix-Temperature_Sensor对应的测试程序为matrix-temperature_sensor。
+
Generated library files are under the "install/lib" directory. Applications are under the "install/usr/bin" directory. The test program for the "Matrix-Temperature_Sensor" module is "matrix-temperature_sensor".
  
−
===运行测试程序===
+
===Run Test Program===
−
拷贝库文件和测试程序到Tiny4412的UbuntuCore的文件系统上
+
Please copy the library files and test program to the Tiny4412
 
<syntaxhighlight lang="bash">
 
<syntaxhighlight lang="bash">
 
$ cp install/usr/bin/* tiny4412_rootfs/usr/bin/
 
$ cp install/usr/bin/* tiny4412_rootfs/usr/bin/
Line 185: Line 384:
 
</syntaxhighlight>
 
</syntaxhighlight>
  
−
然后启动Tiny4412，在UbuntuCore的shell终端中执行如下命令运行模块Matrix-Temperature_Sensor的测试程序 <br>
+
Power on the Tiny4412 and run the following command in UbuntuCore's terminal <br>
−
注意：此模块并不支持热插拔，启动系统前需要确保硬件正常连接。
+
Note: this module is not plug and play therefore before running the module please make sure it is connected to a Tiny4412.
 
<syntaxhighlight lang="bash">
 
<syntaxhighlight lang="bash">
 
$ matrix-temperature_sensor
 
$ matrix-temperature_sensor
 
</syntaxhighlight>
 
</syntaxhighlight>
  
−
===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 221: Line 420:
 
</syntaxhighlight>
 
</syntaxhighlight>
  
−
==与RaspberryPi连接使用==
+
==Connect to RaspberryPi==
  
−
==与Arduino连接使用==
+
==Connect to Arduino==
 +
--->
  
−
==相关资料==
+
==Resources==
 
[http://datasheets.maximintegrated.com/en/ds/DS18B20.pdf DS18B20.pdf]
 
[http://datasheets.maximintegrated.com/en/ds/DS18B20.pdf DS18B20.pdf]
  
−
 
+
==Update Log==
 +
===Feb-23-2016===
 +
* Added the description for "NanoPi 2 branch" in Section 4
 +
* Added Section 5: Connect to NanoPi 2
 +
===June-24-2016===
 +
* Re-organized and simplified wiki
  
 
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Latest revision as of 16:01, 24 June 2016

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1 Introduction

Temperature Sensor
  • The matrix-temperature_sensor module is used to measure temperature.
  • We utilitze the DS18B20 chip with the To-92 package in this module. Its unique 1-wire interface requires only 1 port pin for reading/writing. Power for reading, writing, and performing temperature conversions can be derived from the data line itself with no need for an external power source. The DS18B20 can be powered from its data line. Each DS18B20 is assigned a unique ID.
  • Its temperature range is -55 degree Celsius to +125 degree Celsius. The thermometer resolution is programmable from 9 to 12 bits. When the measured temperature is between -10 degree Celsius to +85 degree Celsius the accuracy can be at 0.5 degree. Among all three DS18B20 pins V is power, G is ground and S is data.

2 Features

  • -55 degree Celsius to +125 degree Celsius
  • One wire interface for communication
  • Tiny, easy to be deployed in various situations
  • 2.54mm spacing pin
  • PCB dimension(mm): 8 X 24

Temperature Sensor PCB


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

3 Basic Device Operation

The core functionality of the DS18B20 is its direct-to-digital temperature sensor. The resolution of the DS18B20 is configurable (9, 10, 11, or 12 bits), with 12-bit readings the factory default state. This equates to a temperature resolution of 0.5°C, 0.25°C, 0.125°C, or 0.0625°C. Following the issuance of the Convert T [44h] command, a temperature conversion is performed and the thermal data is stored in the scratchpad memory in a 16-bit, sign-extended two’s complement format. The temperature information can be retrieved over the 1-Wire interface by issuing a Read Scratchpad [BEh] command once the conversion has been performed. The data is transferred over the 1-Wire bus, LSB first. The MSB of the temperature register contains the “sign” (S) bit, denoting whether the temperature is positive or negative.

4 Applications

4.1 Connect to NanoPi M1

Refer to the following connection diagram to connect the module to the NanoPi M1:
Matrix-Temperature_Sensor_nanopi_m1

Connection Details:

Matrix-Temperature_Sensor NanoPi M1
S Pin7
V Pin4
G Pin6

4.2 Connect to NanoPi 2

Refer to the following connection diagram to connect the module to the NanoPi 2:
Matrix-Temperature_Sensor_nanopi_2

Connection Details:

Matrix-Temperature_Sensor NanoPi 2
S Pin7
V Pin4
G Pin6

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-Temperature_Sensor_nanopi_m2

Connection Details:

Matrix-Temperature_Sensor NanoPi M2
S Pin7
V Pin4
G Pin6

4.4 Connect to NanoPC-T2

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

Connection Details:

Matrix-Temperature_Sensor NanoPC-T2
S Pin15
V Pin29
G Pin30

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-temp_sensor

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 temperature is 27.312 C

The module successfully read the environment's temperature.

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-temperature_sensor". Here is its source code: 

int main(int argc, char ** argv)
{
    char temperature[BUF_SIZE], modStr[BUF_SIZE];
    int board;
    int pin=GPIO_PIN(7);
 
    if ((board = boardInit()) < 0) {
        printf("Fail to init board\n");
        return -1;
    }
    if (board == BOARD_NANOPI_T2)
        pin = GPIO_PIN(15);
 
    if (argc == 2)
        pin = atoi(argv[1]);
    sprintf(modStr, "modprobe %s gpio=%d", TEMP_GPIO_DRIVER_MODULE, pintoGPIO(pin));
    printf("%s\n", modStr);
    system(modStr);
    system("modprobe "TEMP_DRIVER_MODULE);
    sleep(1);
    memset(temperature, 0, BUF_SIZE);
    if (ds18b20Read(temperature) > 0) {
        printf("The temperature is %.3f C\n", atoi(temperature)/1000.0);
    } else {
        printf("Fail to get temperature\n");        
    }
    system("rmmod "TEMP_GPIO_DRIVER_MODULE);
    system("rmmod "TEMP_DRIVER_MODULE);
    return 0;
}

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


7 Resources

DS18B20.pdf

8 Update Log

8.1 Feb-23-2016

  • Added the description for "NanoPi 2 branch" in Section 4
  • Added Section 5: Connect to NanoPi 2

8.2 June-24-2016

  • Re-organized and simplified wiki


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