Hey, here is a diagram of my inverter/PC power-on/shutdown control.
It's a pretty big picture, but the file size is small. Less than 50k.
http://www.dynamic-i.com/carpc/inver...-controlle.gif
Here's a smaller version.
Quickly-found link to cube timer:
Here's one for $20.
http://www.weisd.com/store2/NATQ4F-00010-326.html