The base contains the electronics and there will be a version to house an Ardunio Nano or a Node MCU, and has a place for an LDR sensor, and a ATC type fuse (planning to use a 1A or 2A fuse depending on the current I end up using). The Arduino Nano mount is remixed from AlpoHassinen's Arduino Nano Holder posted at Thingiverse. The fuse holder will require the parts from Erik Cederberg's design posted on Thingiverse by sk8rjess, here. The base also includes some pockets to catch some screws or nails for wall mounting.
It's a bit more than half printed now.