LinkIt ONE 結合 IBM BlueMix 雲服務 – 即時檢測 DHT11 溫濕度感測器資料

本文是參考 IBM 開發者論壇上 IoTGeek 網友的教學，使用聯發科 LinkIt ONE 開發板經由 Wi-Fi 連上 IBM Bluemix 雲服務。

前置作業：

1. 註冊 IBM Bluemix ID (可免費試用 30 天)
2. 作業系統：Microsoft Windows XP/Vista/7/8 或 Mac OS X 10.9 以上。請確認您的電腦已經安裝上述版本的 Arduino IDE 與 LinkIt ONE SDK：教學請點我。
3. Arduino IDE：版本需為 1.5.6-r2 BETA 與 1.5.7 BETA，這是為了配合 LinkIt ONE SDK 的緣故。
4. 請確認您知道如何將 LinkIt ONE 連上 WiFi：教學請點我

下載 LinkItONE-IBMBluemix 範例程式並修改對應參數

1. 請由此下載範例草稿碼：https://github.com/iotgeek/LinkItONE-IBMBluemix
2. 請根據本網頁說明來完成 https://github.com/iotgeek/LinkItONE-IBMBluemix/blob/master/README.md
3. 如果您有 Grove 擴充板的話，請將其裝上 LinkIt ONE，接著在 D2 腳位上裝一個溫度感測器。

1. 在 Arduino IDE 中開啟 quickstart.ino (在剛剛下載的 .zip 檔中)，請將其中的 WiFi 相關資訊(帳號、密碼與 WPA/WEP 加密方式等)修改為您的環境參數。
2. 在草稿碼中修改 servername，格式：”666666.messaging.internetofthings.ibmcloud.com“, “666666” 是您的組織 (organization) 名稱
3. 在草稿碼中修改 clientName，格式：”LinkItONE: aabbccddeeff “，”aabbccddeeff ” 是 MAC Address，以 LinkIt ONE 來說就是 2CXXXXXXXXXX (寫在 LinkIt ONE 背面，如下圖)；”666666″ 是您的組織 (organization) 名稱 ，裝置種類則是 LinkItONE。

[pastacode lang=”c” message=”” highlight=”” provider=”manual”]

#define WIFI_AP “your_ap_ssid”                  
// WiFi AP 名稱

#define WIFI_PASSWORD “your_password”      
// 輸入 WiFi AP 密碼

#define WIFI_AUTH LWIFI_WPA
// choose from LWIFI_OPEN, LWIFI_WPA, or LWIFI_WEP, depending on security type of your WiFi access point.

char macstr[] = “aabbccddeeff”;
// Enter the device mac address here. You can see the WiFi MAC address printed on the backside                                                                                of the LinkIt ONE board.

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上傳並執行

編譯並上傳這份草稿碼到 LinkIt ONE，上傳好之後板子就會連上 WiFi AP (一切順利的話)，接著板子就會把溫濕度資料以 MQTT 訊息格式送到 IBM Bluemix。

請用網頁瀏覽器開啟：https://quickstart.internetofthings.ibmcloud.com/#/ ，請在畫面左側輸入您剛剛在 quickstart.ino 中所修改的同一組 MAC Address，再按下 “Go” 就可以看到來自 LinkIt ONE 的即時溫溼度資料：

執行畫面如下圖。您也可以從同一個帳號下管理所有連到您的 IBM Bluemix 下的各種裝置。

 

quickstart.ino

[pastacode lang=”c” message=”quickstart.ino” highlight=”” provider=”manual”]

/*
  MQTT IOT Example - LinkIt One board to IBM Bluemix Connection quick start
 - continuously obtains values from the Virtuabotix DHT11 temperature/humidity sensor
 - formats the results as a JSON string for the IBM IOT example
 - connects to an MQTT server (either local or at the IBM IOT Cloud)
 - and publishes the JSON String to the topic named quickstart:MY_MAC_ADDRESS
 */



#include 


#include 
#include 
#include "DHT.h"

/* PubSubClient has been taken from https://github.com/knolleary/pubsubclient/tree/master/PubSubClient */
#include 

#define DHTPIN 2     // what pin we're connected to
#define DHTTYPE DHT22   // DHT 22  (AM2302)

/* Modification Needed : 
   Enter your WIFI Access Credentials. 
*/
#define WIFI_AP "your_ap_ssid"
#define WIFI_PASSWORD "your_password"
#define WIFI_AUTH LWIFI_WEP  // choose from LWIFI_OPEN, LWIFI_WPA, or LWIFI_WEP.



char macstr[] = "aabbccddeeff";  // Enter the device mac address here



// Note this next value is only used if you intend to test against a local MQTT server
byte localserver[] = {192,168,1,196};

char servername[] = "quickstart.messaging.internetofthings.ibmcloud.com";
String clientName = String("d:quickstart:arduino:") + macstr; 
String topicName = String("iot-2/evt/status/fmt/json");

float tempF = 0.0;
float tempC = 0.0;
float humidity = 0.0;

DHT dht(DHTPIN, DHTTYPE);
LWiFiClient wifiClient;
PubSubClient client(servername, 1883, 0, wifiClient);

// Uncomment this next line and comment out the line after it to test against a local MQTT server
//PubSubClient client(localserver, 1883, 0, ethClient);


void InitLWiFi()
{
  LWiFi.begin();
  // Keep retrying until connected to AP
  Serial.println("Connecting to AP");
  while (0 == LWiFi.connect(WIFI_AP, LWiFiLoginInfo(WIFI_AUTH, WIFI_PASSWORD)))
  {
    delay(1000);
  }
  
  
  Serial.println("Connected to AP");
}

void setup()
{
   Serial.begin(9600);
   dht.begin();
   InitLWiFi();
}

void loop()
{
  IPAddress server(localserver);
  
  char deviceName[] = "Linkitone";
  char clientStr[34];
  clientName.toCharArray(clientStr,34);
  char topicStr[26];
  topicName.toCharArray(topicStr,26);
  
  
  getData();
  
 


  if (!client.connected()) {
    Serial.print("Trying to connect to: ");
    Serial.println(clientStr);
   
    Serial.println("Connecting to server "); 
    while (! client.connect(clientStr))
    {
      Serial.println("Re-Connecting to SERVER");
      delay(3000);
    }
   Serial.println("Connected to server");
    
  }
  
  if (client.connected() ) {
    
    Serial.println("Connected to server : Building jason");
    
    String json = buildJson();
    char jsonStr[200];
    json.toCharArray(jsonStr,200);
    Serial.println("Connected to server : publishing");
    boolean pubresult = client.publish(topicStr,jsonStr);
    Serial.print("attempt to send ");
    Serial.println(jsonStr);
    Serial.print("to ");
    Serial.println(topicStr);
    if (pubresult)
      Serial.println("successfully sent");
    else
      Serial.println("unsuccessfully sent");
  }
  delay(5000);
}

String buildJson() {
  String data = "{";
  data+="\n";
  data+= "\"d\": {";
  data+="\n";
  data+="\"myName\": \"LinkIt ONE DHT11\",";
  data+="\n";
  data+="\"temperature (F)\": ";
  data+=(int)tempF;
  data+= ",";
  data+="\n";
  data+="\"temperature (C)\": ";
  data+=(int)tempC;
  data+= ",";
  data+="\n";
  data+="\"humidity\": ";
  data+=(int)humidity;
  data+="\n";
  data+="}";
  data+="\n";
  data+="}";
  return data;
}

void getData() {

    // Reading temperature or humidity takes about 250 milliseconds!
    // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
    if(dht.readHT(&tempC, &humidity))
    {
        Serial.println("------------------------------");
        Serial.print("temperature = ");
        Serial.println(tempC);
        tempF = (tempC * 2 ) + 30;
        
        Serial.print("humidity = ");
        Serial.println(humidity);
    }
    
    delay(2000);

}

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