I just did this last week with a Pi Zero and put it in my RainDial (Irritrol) box. I didn’t even have to open the side of the box with the 24AC power supply, I just de-terminated the 24V wires from the old board and landed them on the OSPi board. Removing the old main board in this box was easy and the OSPi fit right in it’s place. I’ve got a micro wifi adapter on the PiZero and I couldn’t be happier with the performance of the whole package.
