===== YUN Notes =====
 
  * Default login is root and password is arduino

In order to use the DD-Wrt side of the YUN with Arduino it is necessary to use the bridge function.  This example shows using an MQTT client on the Arduino side hooked to the DD-Wrt side with the bridge.

     #include <pubsubclient.h>
     #include <yunclient.h>
     void callback(char* topic, byte* payload, unsigned int length) {
     // handle message arrived
     }
     YunClient yun;
     PubSubClient client("192.168.2.210", 1883, callback, yun);
     void setup()
     {
     Bridge.begin();
     } 


==== The aha Moment ====

----

Instead of doing this with EthernetClient, on say, a Duemilanove with an Ethernet shield:

     #include <Ethernet.h>
     ...
     EthernetClient eth;
     PubSubClient mqtt(MQTT_SERVER, MQTT_PORT, callback, eth);
     ...
     Ethernet.begin(mac);
     ...
     mqtt.connect(MQTT_CLIENTID, ....);

you do this with the Yun:

     #include <YunClient.h>
     ...
     YunClient yun;
     PubSubClient mqtt(MQTT_SERVER, MQTT_PORT, callback, yun);
     ...
     Bridge.begin();
     ...
     mqtt.connect(MQTT_CLIENTID, ....);

The bridge opens the connection to the outside world from the Arduino via the OpenWRT host.