GitHub Repository Up and Running

Thank you for so much good feedback. There have been people asking about a GitHub repository for the code to do the safe shutdown.
There you go.
Full instructions are in for how to get the software. Of course, you may modify it, based on your needs/skill level, but the posted instructions should get it running on your Raspberry Pi Zero.
Because this is a GitHub repository, you’ll need internet access on your Pi, so I recommend either doing this in one of the following ways: all on a full size Raspberry PI, using a USB WIFI dongle on a Pi Zero, or using a Pi Zero W that is connected to WIFI.