MQTT with “Arduino” WiFi dev. Board

[MENG XI]

MQTT is a machine-to-machine (M2M)/"Internet of Things" (IOT) connectivity protocol. It was designed as an extremely lightweight publish/subscribe messaging transport.

 

With an Arduino-compatible wireless soc, e.g. Realtek Ameba1 (RTL8195/RTL8710) dev. Board, we can create a MQTT client that sends our sensor data to the cloud or any other MQTT clients.

 

The source code is available on github at,

https://github.com/ambiot/amb1_arduino/blob/master/Arduino_package/hardware/libraries/MQTTClient/examples/mqtt_basic/mqtt_basic.ino

 

The things that need to take note of,

·       The "mqttServer" refers to the MQTT-Broker, we use the MQTT sandbox "test.mosquitto.org", it is provided by IBM eclipse for developers to test MQTT.

·       "clientId" is an identifier for MQTT-Broker to identify the connected device.

·       "publishTopic" is the topic of the published message, we use "outTopic" in the example. The devices subscribe to "outTopic" will receive the message.

·       "publishPayload" is the content to be published.

·       "subscribeTopic" is to tell MQTT-broker which topic we want to subscribe to.

 

Here we can use a chrome plugin "MQTTLens" to be a second MQTT client. You can find it in Chrome Web Store at,

https://chrome.google.com/webstore/detail/mq-tt-lens-the-best/cgmogjdjpnemdlijokkdomfapcodiohh?utm_source=chrome-ntp-icon

 

After setting up a “connection” and key in the same topics we used on Ameba, we should be able to see a “Hello World” message printed on the MQTT message console.