So I have been building a few portable things with Raspberry Pi Zero lately and I’ve been using the Adafruit PowerBoost board. Its a great board for bumping a 3.7V LiPo battery output up to 5.2V for running Raspberry Pi projects, plus it handles charging, has low battery detection and you can turn off the output with a pin. The only problem was being able to do a safe shutdown and then use a pin from the Pi to cut the power. I’m kind of surprised there isn’t a board and prebuilt solution for this and it took a lot of research before I came across NeonHorizons LipoPi repository. The functionality I was after was in the Power Up/ Power Down version and I used the ‘Simple Press’ section as the basis of my circuit. I was using the Adafruit Speaker Bonnet for my project so I could not use the suggested pin 18 and changed it to 27, but the rest stayed the same. Anyway, I put the suggested circuit onto some strip board and the solution worked perfectly so kudos and thanks to Daniel Bull. Check out the repo for the code, instructions and circuit diagrams, my circuit is below.