In this chapter, we enhanced the code of our smart productivity cube, added MQTT to the mix, and learned how to make use of two popular MQTT smartphone apps.

First, we added a stopwatch functionality to our cube. Each side of the cube has its own timer and can be used as an individual stopwatch.

We then learned how to integrate the Arduino MQTT library into our code and how to periodically publish the current side the cube is resting on, as well as the resting time, for example Watching TV: 123 minutes.

Last but not least, we learned how to receive this information on our smartphones, using the third-party apps MQTT Dash and IoT OnOff. Once set up, they can be used to interact with your MQTT prototypes very easily.

I hope you don't stop here, but feel inspired by the vast variety of options and how you can create your own dashboards to display MQTT messages and publish...