Create your own (HMI) Software using OPCUA & Python, Practical demonstration

Practical demonstration of my HMI communicating with my control device (raspberry pi in this case).

Why raspberry pi and python?
I mean what other device seems better for Iot?
PLCs are best for automation but they are expensive.

I have reasons to believe that a PLC is just a computer with microprocessor and i/o channels dedicated for the purpose of controlling, which means if we make a single board computer rugged enough for industrial purpose it could work as a PLC. I don't have much to purchase a PLC and i found raspberry pi to be the best alternative. i programmed the raspberry pi using ladder logic just like a PLC with the aid of CODESYS, and created an OPCUA server with the help of Kepserverex just like a regular PLC.

Then i started developing my client (HMI/SCADA) using python because;
Python is official programming language for raspberry pi,
1. Python is one of the best Programming languages for Iot projects
2. Python is easy to understand
3. Python can be easily used for gui applications with the help of pyqt, which means engineers can easily design their HMI/Scada without much coding knowledge (though i prefer the tkinter to pyqt because i prefer to go through the entire coding experience) and i think even kepserverex (server application used in this project) used python for the server.

I have reasons to believe that a raspberry pi will be best fit for home and automobile automation/Iot projects and with some modifications, a raspberry pi can be tuned for few industrial purposes, this will save small industries that can't afford PLC and its Software from unnecessary costs. And that is the addition to knowledge (relevance) of this project.