You can't configure the PC OS to not go into Sleep mode?
The device will always be on, so sleep is already disabled. My problem is that I need to turn the machine on after an occasional power loss, during the night.
You didn't provide your OS, but my windows machines reboot upon a power loss.
its not windows that controls that, its the bios. check for a resume after power loss entry.
It's probably easier to tie the arduino to the PC power switch or keyboard port.
Does anyone know of a device that exists that does nothing but send broadcast WOL signals over ethernet?