The first device skips the 5V regulator, as I am testing it with a raspberry pi. Everything is red, even the LED. I began to test it for the raspberrry pi as this needs the additional python software required to shut-down the pi safely. I am thinking to implement the functionality of a power button as well, will be a simple one, since the Pi does not have such functionality.

To contact the side ISP connector I use a home made PCB with a simple 90 degrees connector with pins slightly bent

And brief tests with the Pi, shutdown during the warning time works smoothly.