There's also an external button now making use of the arduino and USB interface.
https://www.amazon.de/clouddrive/share/I3ufg6gEgNUMCeOoxh0XAGBb58bwZfbLfr14iQeKNgd
Again Guy - please feel free to use it as you like, e.g. here:
http://pclapcounter.be/power_control.html
http://pclapcounter.be/arduino.html
Regards - Gerald