The link I posted should still work with the addition of another relay. Just have the power supply turn off based on the relay that is triggered by the 5V usb from the laptop. To actually turn off the laptop, install a second relay on the power cord of the laptop that will cut the power to it when the ignition goes off. So when the ignition goes off, it triggers the relay that cuts power to the laptop, the power supply stays on, but as soon as the laptop finishes hibernating and shuts off the USB ports, it goes off.
Quote: Originally Posted by
Nola111 
GOC, thanks for that, and great write-up.
Thing is, I already have a Carnetix unit with a P5V installed inside. The P5V is powering my USB hub and my Audigy card. I don't think I should have to get a 2nd P5V just to get this to work right.
With my current setup, there has to be a way to keep the USB stuff powered until the computer completes its hibernation cycle. Problem is, my pc (laptop) is set to hibernate when the AC power is removed. The trigger that removes the AC power is me turning off the ignition. Me turning off the ignition also cuts power to the USB items, but does so before the pc has a chance to hibernate. (you mentioned this as being the big problem in your write-up).
I have to figure out a way to get my USB periphs (or at least just the Audigy) to stay powered until the pc hibernates. Right now, the only way to do it is to manually hibernate the pc through Windows, wait until it is done hibernating, then shut off the engine. Lame
