@cnoto For the ONOFFSHIM I used the default setup, proposed by Pimoroni. For the complete powercut you either need a systemd file or you set a dtoverlay to /boot/config.txt

You can take a look here to this tutorial

@VaultDweller did you look at the booklet that came with the case? If you lost yours I remember another post around here with the instructions, if I can find it...

I like that suggestion even more than mine :-)

Ehm, I don't recall, and I don't feel like opening up my cab right now.

But I don't think it matters much. You will need to use a transistor able to supply current needed by your fan, which likely will be most of them.
Have a look at this article for some more background.

@flop said in Fan GPIO and code control:

If your fan makes much noise, you could change the GPIO voltage pin of 5v to 3.3v!.

i dont think thats a good idea....fan draws too much current....