Date calculation on Nextion HMI for a date picker or calendar applet - part I While the work on the Nextion MEGA IO project goes on in the background, making our hyper efficient custom protocol fit for a future CAN bus use, a question or better a feature request for a calendar popped up in

Our long-time occupation on which we learn and grow at the same time, the Nextion Mega IO project will, as we have seen in my last blog, see another extension (CAN BUS) soon, which requires our custom protocol to be still more quick and flexible as its is already. That was for me the moment to review what had already been done and especially, how it was done. While the number of supported data types doesn't stop growing, we've seen in the past that adding these to our custom protocol was pretty straightforward, since everything had been well thought and designed from the beginning. But when I look back at our code on both sides, Arduino and Nextion, I find now that although it's currently working surprisingly well, it is sometimes difficult to understand a few weeks later, what was done and how it was done. Time to make our code more self explaining! But as always, let's take a little time to think and to study before going into "medias res" as the Romans said.

Over the last months, we have seen a huge progress in the Nextion Mega IO project. Time for a little break to answer recurring readers' questions. Today, we'll talk about data formats in binary communication. An important point as soon as we leave the default ASCII command communication using the Nextion instruction set. For the Nextion Mega IO project, we introduced a much more compact binary protocol, first to gain on transmission speed, second to showcase the Nextion's protocol reparse mode, and third because it's fun to explore new paths ;-) . Our goal for today is to understand a bit of theory which will allow us to rework somewhat the Nextion Mega IO code in the future to make it simpler, easier maintainable and readable, and still more flexible. Then, adding the control over the up to 32 GPIO pins which we still have to implement, will be very easy. And later, when it comes to high speed communication between Arduino and Nextion for a CAN bus project (spoiler!), we will be thankful for all this preliminary work!

As we have seen in part 1 of this article series, we need an external MCU, for example an Arduino, to control servo motors with our beloved Nextion HMIs. Now, let's see how this can be achieved in practice. Since we are already building a universal IO engine with the ongoing Nextion Mega IO project, we will not reinvent the wheel. We'll just extend what we already have at hands.

Over the last weeks, I got several mails from readers asking about the use of servo motors (or short, servos) together with Nextion HMI. The ones wanted to control a few servos directly from the Nextion's (Enhanced and Intelligent series) GPIO, others suggested to extend the Nextion Mega I/O project to allow controlling servos. The scientific approach is to gather information before taking a decision or even starting a development, thus, let's look at how servos work and how they are controlled, first. And then, let's see how the Nextion HMI can be used for that.