MQTTAndCayenne < AFNOG

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%SLIDESHOWSTART%
---+ Setting up an !IoT
<h1 align="center">Session 3: MQTT and Cayenne</h1> <h1 align="center">Uli Raich<br /><br />Formally CERN, Geneva, Switzerland</h1>

---++ 
---+ The Network Layers

The !WeMos D1 mini has a built-in !WiFi interface<br /><br />In order to communicate with other !IoT nodes we must therefore

connect to the !WiFi network first<br /><br />On top of !WiFi we will run a TCP session<br /><br />On top of TCP we will run the MQTT protocol<br /><br />On top of MQTT we have dedicated topics and payloads imposed by Cayenne

---++ 
---+ Accessing the !WiFi network

<img alt="wifiDemoCode.png" height="349" src="%ATTACHURL%/wifiDemoCode.png" title="wifiDemoCode.png" width="547" />
---++ 
---+ Accessing the !WiFi network from Micropython

<img alt="wifiConnect.png" height="803" src="%ATTACHURL%/wifiConnect.png" title="wifiConnect.png" width="1056" />

---++ 
---+ MQTT

MQTT (Message Queuing Telemetry Transport: a publish-subscribe based <br /><br />message protocol running of top of TCP.<br /><br />A processor can subscribe to messages of a certain “topic” and/or it can push its<br /><br />results on a certain topic

<img alt="mqttPostOfffice.png" height="267" src="%ATTACHURL%/mqttPostOfffice.png" title="mqttPostOfffice.png" width="722" />

---++ 
---+ MQTT Demo

<img alt="mqttDemo.png" src="%ATTACHURL%/mqttDemo.png" title="mqttDemo.png" />

---++ 
---+ The Micropython library

<img alt="micropython-lib.png" height="464" src="%ATTACHURL%/micropython-lib.png" title="micropython-lib.png" width="654" />

---++ 
---+ A MQTT example using umqtt.simple

<img alt="umqttDemo.png" height="564" src="%ATTACHURL%/umqttDemo.png" title="umqttDemo.png" width="535" />

---++ 
---+ Sending dummy temperature data

<img alt="mqttDummySensorDemo.png" height="582" src="%ATTACHURL%/mqttDummySensorDemo.png" title="mqttDummySensorDemo.png" width="535" />

---++ 
---+ Receiving commands

Receiving commands is a bit more tricky! We must:<br /><br />
   * Write a callback function and register it with the MQTT client
   * This function takes 2 arguments:
   * The topic
   * The payload
   * Subscribe to the topic
   * Wait forever. The callback function will be executed when a message with the <br />topic we subscribed to, will arrive
---++ 
---+ Subscribe a callback

<img alt="subscribeDemo.png" height="650" src="%ATTACHURL%/subscribeDemo.png" title="subscribeDemo.png" width="539" />

---++ 
---+ Callback result

<img alt="callbackResult.png" src="%ATTACHURL%/callbackResult.png" title="callbackResult.png" />

---++ 
---+ Controlling a LED

In order to control a LED through MQTT we now simply interpret the payload:
   * Message “LED on”
   * Message “LED off”

---++ 
---+ Changed Callback

<img alt="changedCallback.png" height="148" src="%ATTACHURL%/changedCallback.png" title="changedCallback.png" width="369" />

---++ 
---+ Missing functions in IoT
   * MQTT broker should be globally reachable
   * GUI to easily visualize sensor measurements
   * GUI elements to easily control actuators
   * GUI should be accessible through a WEB interface
   * GUI should be accessible through smart phone app
This is what Cayenne supplies

---++ 
---+ Cayenne functionality
   * MQTT broker is accessible at mqtt.mydevices.com<br /><br />
   * Supplies GUI
<img alt="cayenneFunctionality.png" src="%ATTACHURL%/cayenneFunctionality.png" title="cayenneFunctionality.png" />

---++ 
---+ Signing up for Cayenne

Sign up at<br /> https://mydevices.com/cayenne/signup

<img alt="cayenneSignup.png" height="955" src="%ATTACHURL%/cayenneSignup.png" title="cayenneSignup.png" width="904" />

---++ 
---+ Cayenne Start

<img alt="cayenneStart.png" src="%ATTACHURL%/cayenneStart.png" title="cayenneStart.png" />

---++ 
---+ Cayenne Doc

You find the documentation at

https://mydevices.com/cayenne/docs/intro

Contains short introductory video clips, information of Cayenne on Raspberry Pi and Arduino but also how to use Cayenne on any device.

Pointers to the Cayenne MQTT Libraries and their API

<img alt="cayenneDoc.png" src="%ATTACHURL%/cayenneDoc.png" title="cayenneDoc.png" />

---++ 
---+ Installing Cayenne on the Raspberry PI

<img alt="cayenneRPI.png" height="791" src="%ATTACHURL%/cayenneRPI.png" title="cayenneRPI.png" width="1244" />

---++ 
---+ Installing Cayenne on the Raspberry Pi manually

<img alt="cayenne_RPI_ManualInstallation.png" height="791" src="%ATTACHURL%/cayenne_RPI_ManualInstallation.png" title="cayenne_RPI_ManualInstallation.png" width="1244" />

---++ 
---+ Register your Controller Single Board Computers

<img alt="cayenneRegisterRPI.png" height="907" src="%ATTACHURL%/cayenneRegisterRPI.png" title="cayenneRegisterRPI.png" width="1146" />

---++ 
---+ Run Cayenne on the Arduino

<img alt="cayenneArduinoInstall.png" height="791" src="%ATTACHURL%/cayenneArduinoInstall.png" title="cayenneArduinoInstall.png" width="1244" />

---++ 
---+ Basic Arduino Sketch for the Arduino

<img alt="cayenneArduinoSketch.png" src="%ATTACHURL%/cayenneArduinoSketch.png" title="cayenneArduinoSketch.png" />

---++ 
---+ Cayenne Credentials

<img alt="cayenneCredentials.png" height="835" src="%ATTACHURL%/cayenneCredentials.png" title="cayenneCredentials.png" width="1034" />

---++ 
---+ Cayenne network layers

<img alt="cayenneNetLayers.png" height="366" src="%ATTACHURL%/cayenneNetLayers.png" title="cayenneNetLayers.png" width="1415" />

The Cayenne credentials are integrated into the MQTT topic string<br /><br />Value and units are integrated into the payload string

---++ 
---+ Cayenne and Python

This falls under “bring your own thing” !<br /><br />Having a look at the Arduino sketch you can see that it uses the<br /><br />Arduino Cayenne C++ library.<br /><br />Cayenne MQTT libraries are available in<br /><br />
   * C, C++
   * Python
   * Java
and probably a few other languages

---++ 
---+ Cayenne and Micropython

The Python Cayenne Client library depends on the Eclipse Paho MQTT library<br /><br />Micropython uses its own, stripped down “umqtt” (micro mqtt) library

such that the standard Cayenne Client does not work on Micropython<br /><br />but …<br /><br />The Python Cayenne Client is Open Source and can be adapted to umqtt, which is what I did for you.

The adapted Client library uses the same API as the original one,

which means that the example programs work unchanged.

---++ 
---+ The Cayenne Client

When creating a Cayenne Client Class it <br /><br />
   * Initializes its internal variables
   * Checks if the OLED display is connected and if yes, initializes it
   * The Cayenne Client has has a begin method which
   * Connects to !WiFi
   * Connects to the Cayenne MQTT broker at mqtt.mydevices.com
   * Subscribes to commands send by Cayenne
   * Displays its internal state on the OLED display
---++ 
---+ The code to connect to Cayenne

<img alt="cayenneConnectCode.png" src="%ATTACHURL%/cayenneConnectCode.png" title="cayenneConnectCode.png" />

---++ 
---+ Connecting to Cayenne

<img alt="cayenneConnect.png" height="870" src="%ATTACHURL%/cayenneConnect.png" title="cayenneConnect.png" width="806" />

---++ 
---+ The empty Cayenne dashboard

<img alt="cayenneEmptyDashboard.png" src="%ATTACHURL%/cayenneEmptyDashboard.png" title="cayenneEmptyDashboard.png" />

---++ 
---+ Send dummy measurement

<img alt="cayenneDummyTemp.png" height="538" src="%ATTACHURL%/cayenneDummyTemp.png" title="cayenneDummyTemp.png" width="704" />

---++ 
---+ Dummy temperature in Cayenne

<img alt="dummyTemp.png" height="697" src="%ATTACHURL%/dummyTemp.png" title="dummyTemp.png" width="923" />

---++ 
---+ Dummy temperature parameters

<img alt="dummyTempPars.png" height="840" src="%ATTACHURL%/dummyTempPars.png" title="dummyTempPars.png" width="950" />

---++ 
---+ Fix widget to dashboard

<img alt="dummyTempFixed.png" height="840" src="%ATTACHURL%/dummyTempFixed.png" title="dummyTempFixed.png" width="950" />

---++ 
---+ Dummy temperature history

Cayenne keeps measurement values which can be plotted as a history plot

or downloaded for further evaluation

<img alt="dummyTempHistory.png" height="433" src="%ATTACHURL%/dummyTempHistory.png" title="dummyTempHistory.png" width="595" />

---++ 
---+ A custom widget

<img alt="cayenneCustonWidget.png" src="%ATTACHURL%/cayenneCustonWidget.png" title="cayenneCustonWidget.png" />
---++ 

---+ A gauge widget

<img alt="cayenneTempGauge.png" src="%ATTACHURL%/cayenneTempGauge.png" title="cayenneTempGauge.png" />

---++ 
---+ Dummy temperature gauge on the dashboard

<img alt="cayenneWarm.png" height="929" src="%ATTACHURL%/cayenneWarm.png" title="cayenneWarm.png" width="1134" />

---++
---+ Gauge value ranges

<img alt="cayenneGaugeRanges.png" height="929" src="%ATTACHURL%/cayenneGaugeRanges.png" title="cayenneGaugeRanges.png" width="1134" />

---++ 
---+ It's hot!

<img alt="cayenneHot.png" src="%ATTACHURL%/cayenneHot.png" title="cayenneHot.png" />

---++ 
---+ Several dummy measurements

Now we want to send a dummy temperature and a dummy humidity value.<br /><br />How do we distinguish?<br /><br />They use different communication _channels_!

---++ 
---+ Sending temperature and humidity: the code

<img alt="cayenneTempHum.png" height="618" src="%ATTACHURL%/cayenneTempHum.png" title="cayenneTempHum.png" width="705" />

---++ 
---+ Dashboard with temperature and humidity

<img alt="cayenneDashboardTempHum.png" height="690" src="%ATTACHURL%/cayenneDashboardTempHum.png" title="cayenneDashboardTempHum.png" width="1059" />

---++ 
---+ Other measurements

We have seen that we can send temperature with<br /><br />
   * client.celsiusWrite(channel,temp)
And relative humidity with<br /><br />
   * Client.humidityWrite(channel,hum)
Which other types of measurements can we send?

---++ 
---+ Measurements implemented in the Cayenne Client

<img alt="cayenneMQTTCalls.png" height="673" src="%ATTACHURL%/cayenneMQTTCalls.png" title="cayenneMQTTCalls.png" width="1294" />

---++ 
---+ How to control a device?

Cayenne supplies only 2 control widgets:<br /><br />
   * a push button
   * A slider
---++ 
---+ Cayenne Slider

<img alt="cayenneDummySlider.png" height="819" src="%ATTACHURL%/cayenneDummySlider.png" title="cayenneDummySlider.png" width="1117" />

We can define the range for the slider in the above case: 0..255

---++ 
---+ Slider on the dashboard

<img alt="cayenneDashSlider.png" height="819" src="%ATTACHURL%/cayenneDashSlider.png" title="cayenneDashSlider.png" width="1117" />

---++ 
---+ A Cayenne Button

<img alt="cayenneDummyButtton.png" height="942" src="%ATTACHURL%/cayenneDummyButtton.png" title="cayenneDummyButtton.png" width="1155" />

---++ 
---+ Dashboard with button

<img alt="cayenneDashButton.png" src="%ATTACHURL%/cayenneDashButton.png" title="cayenneDashButton.png" />

---++ 
---+ How to receive commands

We must define a callback function, which is called

whenever the user of the Cayenne dashboard

changes a setting on the push button or slider<br /><br />The callback takes a message parameter which is a tuple of

   * Cayenne topic
   * Cayenne payload
---++ 
---+ Cayenne command message

<img alt="cayenneCmdMsg.png" height="870" src="%ATTACHURL%/cayenneCmdMsg.png" title="cayenneCmdMsg.png" width="806" />

Please compare the command message with our credentials and try to find out

to which channel this command has been addressed. Can you find the values as well?

Remember: we defined the push button on channel 3 and the slider in channel 2!

---++ 
---+ Exercises!

More on how to interpret this message in the next session

%SLIDESHOWEND%

-- %USERSIG{UliRaich - 2019-05-14}%

---++ Comments

%COMMENT%

Attachments

Topic attachments
I	Attachment	History	Action	Size	Date	Who
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png	cayenneArduinoSketch.png	r1	manage	191.2 K	2019-05-22 - 16:35	UliRaich
png	cayenneCmdMsg.png	r1	manage	189.5 K	2019-05-22 - 19:15	UliRaich
png	cayenneCmdMsg2.png	r1	manage	68.6 K	2019-05-22 - 19:15	UliRaich
png	cayenneConnect.png	r1	manage	137.9 K	2019-05-22 - 16:52	UliRaich
png	cayenneConnectCode.png	r1	manage	56.8 K	2019-05-22 - 16:52	UliRaich
png	cayenneCredentials.png	r1	manage	109.7 K	2019-05-22 - 16:36	UliRaich
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png	cayenneDashButton.png	r1	manage	156.5 K	2019-05-22 - 19:03	UliRaich
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png	cayenneHot.png	r1	manage	147.2 K	2019-05-22 - 18:32	UliRaich
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png	cayenneRPI.png	r1	manage	150.8 K	2019-05-22 - 16:24	UliRaich
png	cayenneRegisterRPI.png	r1	manage	148.3 K	2019-05-22 - 16:24	UliRaich
png	cayenneSignup.png	r1	manage	122.2 K	2019-05-22 - 16:15	UliRaich
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png	mqttDummySensorDemo.png	r1	manage	74.4 K	2019-05-20 - 18:40	UliRaich
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png	realData.png	r1	manage	27.7 K	2019-05-15 - 17:12	UliRaich
png	subscribeDemo.png	r1	manage	78.3 K	2019-05-20 - 18:45	UliRaich
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png	wifiConnect.png	r1	manage	128.4 K	2019-05-14 - 17:18	UliRaich
png	wifiDemoCode.png	r1	manage	43.8 K	2019-05-15 - 16:14	UliRaich

Topic revision: r9 - 2019-05-22 - UliRaich