How to make an on/off button for arduino?

Question

Arduino

How to make a power button like in modern phones with turning the device on and off with a time delay and use it to block the device from unlocking.
While it comes to mind - a generator and a counter for organizing a delay, a couple of triggers and a field worker.
Use a button with two contact groups and use the second one to go to and exit sleep mode.
But somehow too much, it seems. maybe there are better options.

Answer 1

Of course there is .
In principle, this is how it is implemented in mobile phones.
One problem with some Arduinos is that there is a bug in the bootloader that can be fixed by replacing the bootloader with a custom one.

Answer 2

The microcontroller has a sleep mode function. You can wake up the Arduino by pressing a button.
I recommend reading the article Waking Arduino from sleep mode by pressing a button .