Some time has passed now and it is finally time to get it to the final product: to enclosure it into a 10 x 10 cm case (home 2 x 2 interruptor case), and route every single wire that's in it to fit and connect correctly to the circuit. I figured that 2 of the 7x3 cm perforated PCBs would be enough for the main circuit would be enough to hold everything in place. It actually turned out a very nice circuit!  The only part I could not put in them is the power supply, as it was from another device that was decomissioned years ago and I never found a use for it until now, so I could not mess with it very much. I ended up puting the PSU into another outlet box and pulled some cables from there to where the dimmer has been planned to be. Connections made, and after a few hours of elbow grease I finally managed to reroute the mains and lamps cables to fit in the box with the circuit and the display! But still there was something missing: how do I get the display and the PIR sensor to fit into a blank cover?

After a few measurements, I figured that I could cut a blank cover to its exact size, and place the PIR sensor just below it. As I don't have a 3D printer, and nowhere to be found a blank cover to fit both display and sensor, I went to cut a simple blank to its size. With the help of some glue, I was able to fit and secure both in place, and after some mechanical testing, I was satisfied with the result!