IOT實驗

1.Hello world mBed
    1.到mbed網站申請帳號
    2.加入devivce
    3.creat project
2.溫度sensor實驗
   1.到Study spec
      http://www.seeedstudio.com/wiki/index.php?title=Main_Page#Grove
      http://www.seeedstudio.com/wiki/Grove_-_Starter_Kit_Plus
   2.作法參考
       https://www.mokoversity.com/workshop/mbed-school/02-gpio-introduction
3.加上四段顯示器
    1.載入lib
       https://developer.mbed.org/users/Seeed/code/DigitDisplay/
    2.參考
       https://developer.mbed.org/users/yihui/code/Arch_Digit_Display/file/89330707469d/main.cpp
4.上網
    1.載入EthernetInterface這個lib,編譯時會發生error再載入mbed_rtos這個lib
    2.再載入WebSocketClient這個lib
程式碼如下:
#include "mbed.h"
#include "DigitDisplay.h"
#include "EthernetInterface.h"
#include "Websocket.h"

AnalogIn temp(P0_23);
DigitalOut myled(LED1);
DigitalOut myled1(LED2);
DigitDisplay digdisp(P4_29,P4_28);
EthernetInterface eth;
int main() {

    char data[1024];
    float temperature;
    float resistance;
    int B=3975;                  //B value of the thermistor
    int a;
    int ret;

    eth.init(); //DHCP
    eth.connect();
 
    Websocket ws("ws://wot.city/object/554ed61eae74407734000119/send");
    ws.connect();
 
loop:
    a=temp.read()*657;
    resistance=(float)(1023-a)*10000/a; //get the resistance of the sensor;
    temperature=1/(log(resistance/10000)/B+1/298.15)-273.15;//convert to temperature via datasheet
    sprintf( data , "{ \"temperature\": %f }", temperature);
    ret = ws.send(data);
    myled1 = 1;
    wait(0.5);
    myled1 = 0;
    wait(0.5);
    goto loop;
}  
   3.到http://wotcity.com/申請帳號產生一個務間編號將他填到Websocket contruct之中
 
 當裝置連線為live即可利用live App看到溫度數值


5.修改網頁
    1.到http://wotcity.com/docs/dotcity-starter-kit下載網頁包
    2.解壓縮照上面的步驟安裝函示庫
    3.打開網址在網址後面輸入#554ed61eae74407734000119

即可看到溫度計的結果