Multimedia Examples Grouping (Ameba-AIoT#56)

* Multimedia Examples Grouping

- group multimedia examples together according to example code group structure

* Restructure MQTT Example Guides

* Update MQTT Image Example Guide

Author: kevinlookl

source/ameba_pro2/amb82-mini/Example_Guides/MQTT/Set up MQTT Client over TLS.rst

@@ -13,7 +13,7 @@ Materials
 Example
 -------
 
-In this example, Ameba connect to a MQTT broker using TLS authentication. Then send messages as a publisher and receive messages as a subscriber.
+In this example, Ameba connect to a MQTT broker using TLS authentication. Then, send messages as a publisher and receive messages as a subscriber.
 
 Open example at “File” -> “Examples” -> “AmebaMQTTClient” -> “MQTT_TLS”
 

source/ameba_pro2/amb82-mini/Example_Guides/MQTT/Set up MQTT Client to Communicate with Broker.rst

@@ -0,0 +1,95 @@
+Set up MQTT Client-Broker Authenticated Connection with Publish in Callback
+===========================================================================
+
+.. contents::
+  :local:
+  :depth: 2
+
+Materials
+---------
+
+- `AMB82-mini <https://www.amebaiot.com/en/where-to-buy-link/#buy_amb82_mini>`_ x 1
+
+Example
+-------
+
+MQTT (Message Queuing Telemetry Transport) is a protocol proposed by IBM and Eurotech. The introduction in MQTT Official Website:
+MQTT is a machine-to-machine (M2M)/”Internet of Things” connectivity protocol. It was designed as an extremely lightweight publish/subscribe messaging transport.We can say MQTT is a protocol designed for IoT. MQTT is based on TCP/IP and transmits/receives data via publish/subscribe.
+
+Please refer to the figure below:
+
+|image01|
+
+In the operation of MQTT, there are several roles:
+
+-  Publisher: Usually publishers are the devices equipped with sensors
+   (ex. Ameba). Publishers uploads the data of the sensors to
+   MQTT-Broker, which serves as a database with MQTT service.
+
+-  Subscriber: Subscribers are referred to the devices which receive and
+   observe messages, such as a laptop or a mobile phone.
+
+-  Topic: Topic is used to categorize the messages, for example the
+   topic of a message can be “PM2.5” or “Temperature”. Subscribers can
+   choose messages of which topics they want to receive.
+
+This example shows how to connect Ameba to MQTT-Broker with authentication.
+Then, send messages as publisher and receive messages from MQTT-Broker as
+subscriber.
+
+**MQTT_Publish_In_Callback example**
+
+Open the MQTT example “File” -> “Examples” -> “AmebaMQTTClient” ->
+“MQTT_Publish_In_Callback”
+
+Please modify some WiFi-related parameter and some information related
+to MQTT:
+
+|image08|
+
+-  All parameters are same as MQTT_Auth example.
+
+Next, compile the code and upload it to Ameba. Press the reset button,
+then open the serial monitor. After Ameba is connected to MQTT server,
+it sends the message “hello world” to “outTopic”. To see the message,
+another MQTT client needs to be set up.
+
+Start the MQTT Explore, and setup the auth connection. All setting is
+same as MQTT_Auth example.
+
+|image09|
+
+Click “ADVANCED” at bottom for topic setup. Use “outTopic” that same as
+“publishTopic” of the board. Click “ADD” then “BACK”.
+
+Click “CONNECT”. The “hello world” message show up at left side. At
+right side, under “Publish” use “inTopic” same as “subscribeTopic” of the
+board. Choose “raw” and input “Text hello Ameba”, then click “PUBLISH”.
+The board will receive the MQTT Explorer published raw message. Then
+publish it from the board side and MQTT Explorer will receive at the
+left side. Note, “hello world” sometimes is not shown up because the
+boards connect to MQTT broker before the MQTT Explorer.
+
+|image12|
+
+|image13|
+
+.. |image01| image:: ../../../../_static/amebapro2/Example_Guides/MQTT/Set_up_Client/image01.png
+   :width:  940 px
+   :height:  617 px
+
+.. |image08| image:: ../../../../_static/amebapro2/Example_Guides/MQTT/Set_up_Client/image08.png
+   :width:  524 px
+   :height:  217 px
+
+.. |image09| image:: ../../../../_static/amebapro2/Example_Guides/MQTT/Set_up_Client/image09.png
+   :width:  998 px
+   :height:  652 px
+
+.. |image12| image:: ../../../../_static/amebapro2/Example_Guides/MQTT/Set_up_Client/image12.png
+   :width:  1001 px
+   :height:  653 px
+
+.. |image13| image:: ../../../../_static/amebapro2/Example_Guides/MQTT/Set_up_Client/image13.png
+   :width:  548 px
+   :height:  151 px