Understanding the five-zone temperature logger system architecture

The temperature logger was born from two main needs I had. The first need was to try to keep the same temperature throughout the entire house, since it has two HVAC systems and the temperatures in the rooms are not the same. The second need (which came later) arose after some research on how to implement a temperature measurement in the rooms, where I saw the opportunity to learn and use different software tools and hardware devices in my projects. Unfortunately, I didn’t succeed in implementing the feedback control performed by the HVAC controller, due to one of the two installed in my house being too old and a modern controller being incompatible. So, I decided to postpone the HVAC control when replacing the old HVAC. So, the project so far helps me verify and monitor the temperature in six locations in my home. The Kids1 and kids2 bedrooms, the kitchen, and the master bedroom temperatures are indoors. The...