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{{AppliesToSBCLynx}}
{{AppliesTo AXEL ULite AN}}
{{AppliesTo SBC Lynx AN}}
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{{AppliesTo IoT AN}}
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{{WarningMessage|text=This application note was validated against specific versions of the kit only. It may not work with other versions. Supported versions are listed in the ''History'' section.}}
== History ==
{| class="wikitable" border="1"
|-
|0.5.0
|April May 2017
|First draft
|-
|0.6.0
|May 2017
|Added section "Configuring SBC Lynx as an MQTT broker"
|-
|}
==Introduction==
[[:Category:SBC_Lynx|SBC Lynx provides ]] is extremely flexible in terms of [[Connectors,_buttons_and_switches_(SBC_Lynx)|communication interfaces]] and [[Additional_industrial_I/Os_(XUAL)|I/O ports]]. When used in combination with a Linux distribution such as [[XUELK-AN-002:_Running_Debian_distribution|Debian]], it is an ideal solution to implement compact highly-integrated cost-effective gateways/controllers supervisors for [http://internetofthingsagenda.techtarget.com/definition/Industrial-Internet-of-Things-IIoT Industrial Internet of Things applications (IIoT)].
IIoT is a vast field that includes several disciplines. At field level, the typical IIoT system requires
This application note provides some examples of hardware and software configurations that can be used for these purposes. Also, it shows how to harness the versatility of SBC Lynx to integrate on the same platform even processing and controlling functionalities. [1]
The examples were tested on an SBC Lynx board equipped with [[Wireless_Module_(DWM)|optional wireless module]] and that runs Debian distribution, as described [[XUELK-AN-002:_Running_Debian_distribution|here]].
==Cloud interfacing==
At the time of this writing, tens of cloud platforms are available on the market addressing IoT and IIoT applications. [1] Some of them provide free accounts for small projects or evaluation purposes. The following sections describe how to interface an SBC Lynx-based gateway to some of such platforms.
[1] See for example [[#List of IoT cloud platforms (not exhaustive)|this section]].
===Ubidots===
[https://ubidots.com Ubidots] is ''a codeless IoT Platform designed to help you prototype and scale your IoT projects to production''.
This application notes example consists of three step to connect SBC-LYNX to ubidotssteps.The first part describes how shows:*How to connect the sbc-lynx SBC Lynx to ubidots and send Ubidots *How to upload data to the platform (ubidots)cloud.The second part describes how to visualize on the dash board dashboard of the ubidotsThe third part is Ubidots. Tha last one shows how to setup set up events so as to get a notification====Sending data to Ubidots====The SBC LYNX board used specification: CPU: based on NXP/Freescale i.MX6UL2xRS232-2xRS485 on Serial Multi ProtocolOperating Systems: Linux, Debian (Jessie)IEC-61131 PLC runtime Cross Checking the Sbc-lynx board distribution used and the command used to check the distribution is lsb_release –a and looks like the below one
The procedure here described was tested on a SBC Lynx running Debian distribution. For more details, please refer to [[XUELK-AN-002:_Running_Debian_distribution|this application note]].
====Connecting and uploading data to Ubidots====
As stated before, it is assumed that the board runs a Debian distribution:
<pre class="board-terminal">
root@arm:~# lsb_release -a
No LSB modules are available.
Release: 8.7
Codename: Jessie
</pre>
apt-get update
apt-get upgrade
easy_install pip
pip install ubidots
</pre>
[[File:XUELK-AN-IIoT-21.png|thumb|center|600px|caption]]
To get the API token for the just created account, go to the right upper corner of the home page and click on the username. Then you will see four options which are ''My Profile'', ''API Credentials'', ''Docs'' and ''Log Out''.
[[File:XUELK-AN-IIoT-2.png|thumb|center|600px]]
Click the ''API Credentials''. The API token (<code>fwSetosAgIG3d128YdzP5fi4hADzWU</code> in this example) is a string which will be used later to initialize the API client instance.
To create and initialize an API Client instance, use the following code:
<pre class="board-terminal">
from ubidots import ApiClient
api = ApiClient(token=' fwSetosAgIG3d128YdzP5fi4hADzWU ') After establishing the instance with the cloud, we will retrieve the variable.The variable is where we want to save the value that we will send to theCloud. But before sending data to the cloud side, we first go to the device option and define our own device and create the variables (equivalent to sensors)To create variables, there are three option in the upper center of the home page of the ubidots shown below [[File:XUELK-AN-IIoT-4.png|thumb|center|600px|caption]] Click the device option, then we will get the following [[File:XUELK-AN-IIoT-5.png|thumb|center|600px|caption]]</pre>
On the cloud side, it is necessary to create the variables that will store the values uploaded by the SBC Lynx. In the example, three variables are created: <code>Fall_sensor</code>, <code>Flood_sensor</code> and <code>Temp_sensor</code>. To create variables, there are three options in the upper center of the home page of the Ubidots interface, as shown below.
[[File:XUELK-AN-IIoT-4.png|thumb|center|600px]]
Click the device option, then we will get the following:
[[File:XUELK-AN-IIoT-5.png|thumb|center|600px]]
To create an instance of the variable on the SBC Lynx side, use the following format code:
<pre class="board-terminal">
my_variable = api.get_variable('<variable ID>')
</pre>
Following is a code snippet that uploads random data to the platform:
<pre class="board-terminal">
from ubidots import ApiClient
import random
test_value_3 = random.randint(1,10)
test_value_3 = my_variable_3.save_value({'value':test_value_3})
</pre>
====Visualizing data on the cloud dashboards====
To visualize the data sent to Ubidots, we have to use the ''Dashboards'' section, where we can configure how we want to visualize the data.
In this example, the option ''chart'' was selected. As such, several further options are available:
[[File:XUELK-AN-IIoT-9.png|thumb|center|600px]]
For all of the variables, the ''Line chart'' option was chosen. The following image shows how the data visualization looks like:
[[File:XUELK-AN-IIoT-10.png|thumb|center|600px]]
====Events and notifications====Ubidots allows sending notifications—for instance in the form of text messages (SMS) or emails—to the authorized users, based on the events configured on the cloud. In my case, I have selected the first option chartfollowing example, a variable that was not mentioned in this case there are several option to use the previous sections is used (<code>heartbeat</code>).
To configure notification options, click enter the ''Events'' section.
[[File:XUELK-AN-IIoT-11.png|thumb|center|600px]]
Then sekect the device (<code>My_device_1</code> in the example) ...
[[File:XUELK-AN-IIoT-12.png|thumb|center|600px]]
... and click the variable you wish to configure the notification for.
[[File:XUELK-AN-IIoT-13.png|thumb|center|600px]]
After selecting the variable, we will define the condition that triggers the notification. In this case, it is triggered when the <code>heartbeat</code> variable is less than 4:
[[File:XUELK-AN-IIoT-14.png|thumb|center|600px]]
[[File:XUELK-AN-IIoT-15.png|thumb|center|600px]]
Last, we compose the message we want to be emailed every time the notification is triggered.
[[File:XUELK-AN-IIoT-16.png|thumb|center|600px]]
==Device-to-device communications=====Configuring SBC Lynx as an MQTT broker===This example shows how to install an MQTT broker on SBC Lynx, running Debian distribution. "MQTT, a simple, lightweight, publish/subscribe messaging protocol on top of the TCP/IP protocol, is the ideal protocol for the emerging IoT world" [[File:XUELK-AN1] and is becoming one on the most common protocols used for machine-IIoTto-11machine communications.png|thumb|center|600px|caption]]
In contrast to HTTP with its request/response paradigm, MQTT is based on a publish/subscribe model, as depicted in the following image. This makes it suitable for "Internet of Things" messaging where highly constrained devices are used (low power sensors, mobile devices, embedded computers, microcontrollers, etc.).
[[File:MQTT-architecture.png|thumb|center|600px]]
Publish/Subscribe is an event-driven way of communicating and it enables messages to be pushed to clients. The central communication point is the MQTT broker (server). It is in charge of routing all messages between the senders and the rightful receivers. Each client (sensors) that publishes (transmits) a message to the broker includes a topic into the message. The topic is the routing information for the broker. Each client that wants to receive messages subscribes to a certain topic and the broker delivers all messages with the matching topic to the client.
For more details, please refer to the publicly available resources such as [http://www.steves-internet-guide.com/mqtt/ this link].
[[File1] https:XUELK//www.ibm.com/developerworks/cloud/library/cl-mqtt-bluemix-iot-ANnode-IIoTred-12app/====Installing the broker====Eclipse Mosquitto™ broker will be installed on SBC Lynx. Eclipse Mosquitto™ is an open source (EPL/EDL licensed) message broker that implements the MQTT protocol versions 3.1 and 3.1.1.png|thumb|center|600px|caption]]
The procedure was tested on an [[XUELK-AN-002:_Running_Debian_distribution|SBC Lynx running Debian Jessie distribution]].
First, import the repository package signaling key:
<pre class="board-terminal">
wget http://repo.mosquitto.org/debian/mosquitto-repo.gpg.key
sudo apt-key add mosquito-repo.gpg.key
</pre>
Make the reposioty available for the mqtt:
<pre class="board-terminal">
cd /etc/apt/sources.lit.d/
sudo wget http://repo.mosquitto.org/debian/mosquitto-jessie.list
</pre>
Install Mosquitto
<pre class="board-terminal">
sudo apt-get update
sudo apt-get install mosquitto
</pre>
Install Mosquitto developer libraries to develop MQTT clients
<pre class="board-terminal">
sudo apt-get install libmosquitto-dev
</pre>
Execute the following command to install Mosquitto client packages
<pre class="board-terminal">
sudo apt-get install mosquitto-clients
</pre>
Ensure that Mosquitto broker is running
<pre class="board-terminal">
sudo service mosquitto status
</pre>
To verify that the broker is running properly, you can perform this simple test.
Now the message <code>Hello MQTT</code> will be displayed in the first terminal where the topic <code>mqtt</code> was subscribed.
