Yes, I think it is possible to optimize the code. But as I am a newbie, it is quite difficult to optimize the code which will allow me to continue it in Arduino UNO.
And I think it is better to merge my two (UNO and pro mini) code in a single board. So it will good to manage the code and circuit and also cost effective too.
So that I don't need to send data via I2C communication for two Arduino. Only need I2C communication for RTC only.
Yes, I also do this. But the price of Arduino MEGA is much than the Atmega128.
The ATmega128 is also operated using Arduino IDE. You may be happy to hearing that I program Atmega128 with Arduino IDE.
It depends on country or location. What is your location? When I complete it, I will give you a copy without any cost Insha'Allah. Because you help me a lot from the beginning.
Thank you my brother @GolamMostafa for your continuous help and advise.