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• CO2 Data fetch

  h4ltsys • 03/21/2018 at 21:10 • 0 comments

  the first step of the project is to obtained the co2 level data. To do this, I choose to use the HTTPThing app from thingspeak, that allow to fetch data from every site and make it disponible trough an API.

  The MCU that i choose to use is the well know ESP8266. Thanks to the ESP8266HttpClient library i can simply send a GET request to the thinghttp link and receive the daily data from www.co2.earth.

  #include <ESP8266WiFi.h>
  #include <ESP8266HTTPClient.h>
   
  const char* ssid = "MYWIFI";
  const char* password = "*******";
   
  void setup () {
   
    Serial.begin(115200);
    WiFi.begin(ssid, password);
   
    while (WiFi.status() != WL_CONNECTED) {
   
      delay(1000);
      Serial.println("Connecting..");
   
    }
   
  }
   
  void loop() {
   
    if (WiFi.status() == WL_CONNECTED) { //Check WiFi connection status
   
      HTTPClient http;  //Declare an object of class HTTPClient
   
      http.begin("http://api.thingspeak.com/apps/thinghttp/send_request?api_key=YAOX15VANMLMYH4S");  //Specify request destination
      int httpCode = http.GET();                                                                  //Send the request
   
      if (httpCode > 0) { //Check the returning code
   
        String payload = http.getString(); //Get the request response payload
        String todaydate = payload.substring(62,76);
        String todayco2 = payload.substring(118,128);
        Serial.print(todaydate);
        Serial.print(" CO2 Level: "); //Print the response payload
        Serial.println(todayco2);
        httpCode == 0;
        
   
      }
  
      http.begin("http://api.thingspeak.com/apps/thinghttp/send_request?api_key=3TKGGW5Z5CHH7G0S");  //Specify request destination
      httpCode = http.GET();                                                                  //Send the request
   
      if (httpCode > 0) { //Check the returning code
   
        String payload = http.getString();
            String agodate = payload.substring(36,50);
        String agoco2 = payload.substring(92,99);//Get the request response payload
           Serial.print(agodate);
        Serial.print(" CO2 Level: "); //Print the response payload
        Serial.println(agoco2);                    //Print the response payload
   
      }
   
      http.end();   //Close connection
   
    }
   
    delay(30000);    //Send a request every 30 seconds
   
  }

  However co2.earth only maintain data histories about last year. So for the decade CO2 data i will use  a text file downloaded from noaa server that contain world CO2 data from start of 20th century.
  

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