This is one of the ways to remotely control Mac Mini's power button. In rare case of power outage and Power BackUPs depletion Mac can be brought back up by Power Settings "Energy Saver -> Schedule -> Start or wake" if Mac is in high demand - it could be booted by physically pressing Power button.

In my case other Mac Mini checks every hour weather or not main Mac is up or down and if it is not powered-up - it uses a Phidgets Servo controller: http://www.phidgets.com

Any servo that is small enough could be used to press the power button. All that has to be done is gluing it in proper position

I used Elmer's Glue-All white multi purpose glue

In 24 hours it hardens and holds servo in-place with enough force for power button to be pressed

will continue once glue is set.There's no place like ~