Over the last blog episodes we have made our Arduino talk to the Nextion HMI. We even managed to build a simple digital volt meter using just an Arduino and a Nextion. But up to now, we never cared about what the Nextion HMI would have to tell to the Arduino. So, let's attack things from the other side today, and capture the data sent by the Nextion!

In the last episode, we saw how the Arduino could basically send commands over to the Nextion, and we used that for displaying some funny animated texts. Before we move on, it will be needed to look critically back on our code and eliminate some "not so optimal" things. But we will end up with a simple digital volt meter today, and I guess it's worth it.

As promised in last Sunday's blog episode, where we controlled our Nextion HMI directly from our PC using the Python3 command window, we are now up for a few episodes where we'll see in detail, how to hook up and program an Arduino. Over the next weeks, we'll see step by step how to make an Arduino talking to a Nextion, without using a prefabricated library, just by using the well documented ASCII command format. At the same time, this approach allows us to review some basics of the Arduino C/C++ dialect.

In the previous episode, we have learned how using a Nextion HMI makes designing GUIs much simpler and saves most of the time and resources of your MCU, compared to the use of a simple TFT display. We have designed a very simple example GUI, allowing simply to display some text, using the free Nextion Editor, within seconds. Finally, we used the integrated Nextion simulator to test our GUI and to display "Hello world". Today, we move a step forward, we upload the compiled GUI to our Nextion screen and we'll set and change the displayed text "from outside".

In the first episode of this blog series, we learnt about serial communication in general and how it developed and became a standard, historically. Today, we will have a more in-depth look into the Nextion HMI's principle of operation, and do so partly by comparing the Nextion HMI with the use of a standard TFT in common MCU (Arduino) projects.

I have heard your suggestions, encouragements, and critics. The last two Sunday blog series were dedicated to (future) advanced users and we did our best to push the limits of what a Nextion HMI can do in autonomous mode (without any MCU, i.e. Arduino, connected). We will with these new episodes help the beginners with their hands-on. With our Nextion HMIs, it's like everywhere in life: It's always about communication. Let's see and explore how that works in detail!