Short version: Printer finishes, and lowers the hotbed but stays on.
Now printer completely shuts off then the hotbed is lowered. =)

Long version:
So I print a LOT.
I don't sacrifice my time by babysitting or staring at the printer. Plus it stinks.
I have a webcam to remote monitor the printer so I know if it had a problem such as not feeding filament or the part came off the hotbed, also so that I know if the print finished because the hotbed will be lowered outside of the webcam view.

But then I have to go upstairs to turn the printer off so it isn't sitting there running the fan and power supply for no reason.

So I made an "Auto Off!" box to hold a pressure switch, an override power ON switch, a green light for Armed, and a red light for stop.
Now when the webcam shows the hotbed was lowered and therefore the printer is done, it has also shut off the printer completely! (But the webcam stays on unless plugged into the same outlet.)

I then got a 120V AC relay from Radio shack for $5, but the coil runs on 32V DC. Sure I can use a single Diode as a half cycle bridge rectifier and have 60V DC in a snap. But then I have to use Ohms Law bla bla bla for a resistor that would get hot and a bunch of math and run the power cord through it, plus draw 3v DC for the LEDs etc.

I did find this GE Remote controlled power plug thing. Remote long lost. So I wired in a telephone jack to it and the Auto Off box, and Bang! Simple as that! The GE box is just a relay with it's own power supply for it's coil, outlet passthrough and some remote control chips I bypassed after plugging it in and poking around with some continuity probes from the multimeter.

Best printer upgrade ever!
Aside from putting the power switch from the back to the FRONT as it should have been.

I put the Auto Off Box up here so others can try.
Please don't steal my idea and sell it.
I however will sell this as a kit if I can find some more GE boxes.

2 LEDs (optional)
Pressure switch
Override DPDT slider switch.

GE remote power box just because it has a relay.
Instructions for wiring would be a big chore, if you can't figure out that LEDs are just one way diodes, and switches are just... switches.. or how to use a relay then you couldn't handle this and should just buy a kit.
However with the pictures and the idea, many 3D printer people should be able to imitate this easy.

Please share any improved versions of this!
I wish the firmware had a "shutdown when finished = true" option!

If you would like me to build this for you, contact me via activezombie.com or activezombie@gmail.com or youtube.com/wwwactivezomebie

I will find the parts and we go from there.