processing dweet.io reader

Processing and dweet.io  togethor offer a powerful data visualizer for machine to machine processing. Here's a simple way of reading 'dweets' with processing.  Lets see how to grab this data, firstly install processing language by following instructions on processing.org otherwise read on.

dweet.io reader showing console print of sensor data from a mobile phone.

processing.org
dweet.io
download source from github - processing-dweet-reader 

Processing dweet.io reader

This project uses 'JSONObject' to download the dweet.io payload , once 'jsonPayload' variable is updated we can read and convert the various data items.  Now with this data we can control an object for example a 3D object can be moved with the sensor data from a device or maybe a simple graph but if it's just graphing dweet.io has a sister site called freeboard.io
 

JSONObject jsonPayload;

String aThing="tbot-0";  // tbot-0 is our machine that is 'dweeting' happens to be my phone.
float az, pitch, roll, lat, lng, gx, gy, gz;  // What data is this thing producing ?         
int lastm; 

void setup() {
  thread("dweetUpdate");
}


// Thread spins once per second grabbing the payload and filling our local
// data. 
void dweetUpdate() 
{
  int dweet_grab = 0;

  while (true) {
    int m = millis();
    if (m - lastm > 1000) {  // flip dweet_grab 1,0,1,0,0... every second.
      lastm = m;
      dweet_grab =1;
    } else {
      dweet_grab =0;
    }
    // END OF THROTTLE

    if (dweet_grab == 1)
    {
      dweetCollect(aThing);
      try {
        if ( aThing == "tbot-0" ) {  // Change to whatever thing you wish to listen to.
          az = jsonPayload.getInt("az"); // Change to match whatever data it publishes e.g temperature etc.
          pitch = jsonPayload.getInt("pitch");
          roll = jsonPayload.getInt("roll");
          println("dweet.io/follow/" + aThing + "    az: " + az + " pitch: " + pitch + " roll: " + roll);
        }
      }
      catch(Exception e) {   
        // If we don't try/catch you'll see missed payload exceptions etc. plus the JSON data can change at any time ...
        println("failed to parse JSON payload or no data available");
      }

      try {
        if ( aThing == "tbot-0" ) {    
          //  Some dweets are not aggregated into a single payload, so we need another try/catch extract for GPS data.
          lat = jsonPayload.getFloat("lat");
          lng = jsonPayload.getFloat("long");
        }
      }
      catch(Exception e) {
      }
    }
  }
}


// dweet 'read'
void dweetCollect(String thing)
{ 
  JSONObject json;

  try {
    json = loadJSONObject("http://dweet.io/get/latest/dweet/for/" + thing );
    JSONArray values = json.getJSONArray("with");
    for ( int i = 0; i < values.size (); i++) {
      JSONObject  item = values.getJSONObject(i);
      String  theThing = item.getString("thing");        
      String   theDate = item.getString("created"); 
      jsonPayload = item.getJSONObject("content"); // extract just the content JSON
      println("dweetCollect(" +theThing +") " +theDate + jsonPayload);
    }
  }
  catch( Exception e ) {
    println("dweetCollect: failed for " + thing);
  }
}