I know how to turn off and on Arduino!!!
WHAT DO YOU THINK?
you turn off by making a short? oops ...
Yes, but it works and it doesn't damage Arduino.
then I guess you turn the lights off in your room by sticking a wire in the mains :o
Just hope the short circuit protection of whatever power supply you use kicks in.
But on a more serious note: is this thread meant as serious advice or as troll?
I'm joking, it isn't advice but only for a smile 
In this forum where 99.99% of all users do not know the difference between volts and amps nobody recognizes this a joke ... which is a jike on it's self I guess
SFracassetti:
I'm joking, it isn't advice but only for a smile
Considering your very low post number I seriously couldn't be sure.
This gave me a kick. Thanks man 
SFracassetti:
I know how to turn off and on Arduino!!!
WHAT DO YOU THINK?
Easy.
You have to use a rele and give power Arduino thru the NC contact. When you need to reset Arduino, I image by himself, simply drive rele to switch. As it switch, Arduino loss power and rele go back in the normal state, giving power again to Arduino.
Carlo
..or with a Latching relay ?(and a push button to power on again?)
zwieblum:
then I guess you turn the lights off in your room by sticking a wire in the mains :o
My late Dad did exactly that once. I was working in the garage with him one night, and left him to it. From force of habit I locked the pedestrian door to the garage behind me, and one car in the driveway was up against the tip-up door so he was trapped.
He wrapped a wire round the pins on a mains plug and turned it on, knowing that when house went dark we would realise something was amiss in the garage.
(His being late now is nothing to do with that incident, I must stress.)