IoTViaMQTTAndCayenne < IoT_Course

---+ MQTT and Cayenne
---++ Exercise 1:

Install mosquitto on your machine. On Ubuntu Linux this can very easily be accomplished with apt.

Try the _mosquitto_ communication:
   * <p>Start the mosquitto broker</p>
   * <p>Start mosquitto_sub subscribing to the “DCSIT” topic</p>
   * <p>Start mosquitto_pub publishing some message to the topic “DCSIT</p>
   * <p>observe the message being seen in mosquitto_sub</p>
---++ <a name="Exercise_2"></a> Exercise 2:

Write you own MQTT client in Python publishing a message to “DCSIT” every 2 s.

Have a look at the <a href="https://github.com/micropython/micropython-lib/tree/master/umqtt.simple" target="_blank">umqtt.simple class<img alt="" border="0" height="12" src="%PUBURL%/TWiki/TWikiDocGraphics/external-link.gif" width="13" /></a> to see how to accomplish this. Write the program and start it with thonny. You must know the IP address of the machine on which your mosquitto broker is running. Use _ifconfig_ to find out.

Subscribe to the “DCSIT” topic with mosquitto_sub and observer that the messages are arriving.

Write an MQTT client that subscribes to the “DCSIT” topic and that prints messages coming in.

Write a program controlling a LED as we did during the lectures.
---++ <a name="Exercise_3"></a> Exercise 3:

Register a user on <a href="https://mydevices.com/cayenne/signup" target="_blank">https://mydevices.com/cayenne/signup<img alt="" border="0" height="12" src="%PUBURL%/TWiki/TWikiDocGraphics/external-link.gif" width="13" /></a>.

Watch the introductory film and have a look at the documentation pages.

Add a device by clicking on “Bring Your Own Thing”. Have a look at your Cayenne credentials.
---++ <a name="Exercise_4"></a> Exercise 4:

Write a program connecting to Cayenne. Observe that the dashboard is coming up.
---++ <a name="Exercise_5"></a> Exercise 5:

Write a program that sends a dummy voltage value to Cayenne on channel 0. The voltage values should range from 0 to 3300 mV (the voltages on the ESP8266). Wait for 2 s minimum between each value.

Observe the widget coming up on the dashboard.

Fix the widget on the dashboard and change the widget parameters (e.g. the name).
---++ <a name="Exercise_6"></a> Exercise 6:

Add a gauge widget with ranges 0 .. 1V, 1V .. 2V, 2V .. 3.3V. Run your program sending the dummy voltages and observe how the dashboard displays them.
---++ <a name="Exercise_7"></a> Exercise 7:

Add a dummy measurement on atmospheric pressure to your program. The normal air pressure is around 950 hPa (hecto Pascal).
---++ <a name="Exercises_8"></a> Exercises 8:

Create a slider and a push button on your dashboard.

-- %USERSIG{UliRaich - 2020-09-02}%

---++ Comments

%COMMENT%
This topic: IoT_Course_English > WebHome > Exercises > IoTViaMQTTAndCayenne
Topic revision: r1 - 2020-09-02 - UliRaich