Robin2:
Just changelong debouncing_time = 400;to
long debouncing_time = 400000;To be honest, if you can't figure that out without my help you are probably too inexperienced to be using interrupts. Spend some more time learning the basics.
...R
Thanks robin2 for your reply I know I need to learn alot more. But I was asking about how to make those calculations in setup.