Getting started Part 2
##How to build a MQTT SN Linux Client over UDP
- Linux machine and the C ++ development environment
- Arduino Ethernet Rev3 and the Arduino IDE (1.6.4)
- Clients over UDP, one for Linux and the other is for Aruduino.
- MQTT-SN Gateway over UDP
- Arduino client SUBSCRIBE to topic xxxx/onoff/arduino for turning on/off the LED light. When PUBLISH takes place with the boolean value, the LED light turns on/off. And topic xxxx/onoff/linux with False/True PUBLISH alternately.
- Linux client SUBSCRIBE to topic xxxx/onoff/linux for turning on/off LED light. Whenever PUBLISH with the boolean value, result in standard output “ON” or “OFF”. With topic xxxx/onoff/arduino, PUBLISH alternately with True/False.
- Gateway takes these topics, converts between MQTT and MQTT-SN , realy between client and broker.
- From the set-up, LED light on Arduino will flash, and Linux client will be ON/OFF and print out accordingly.
- Gateway will output a communication log into RAM simultaneously, display the log and you should be able to understand MQTT-SN protocol more easily.
$ git clone https://github.com/ty4tw/AsyncMQTT-SN.git
in AsyncMQTT-SN/AsyncClient/src, you can find the source code Application.cpp and the library you need for AsyncMQTT-SN/AsyncClient/src/lib
$ cd AsyncMQTT-SN/AsyncClient
if there is no error, copy the Client program.
$ make install
execution module TomyAsyncClient is then copied to Home Directory.
$ cd
$ ./TomyAsyncClient
At this point, Gateway is not ready so nothing actually happened. However if use wireshark to monitor, you can see that SEARCHGW messages have been sent over UDP.
You can also uncomment line 66 and 67 of MqttsnClientApp.h and compile again. This will get you standard output of the message which was sent over UDP.
