The journey has started with our ventilation system, that is located in de cellar. It is a system with 4 ventilation levels and no remote control. The system had a very useless clock timer and quick changes were not possible without stepping in the cellar. Something has to change! The first idea was to install a remote control, but it should cost around 450 € and this idea has been rejected. 450 € were to much and this topic was on hold!
One Year later I was interested a the efficiency factor of the ventilation system and I found several Raspberry Pi projects with temperature sensors. I the winter vacation I started with setting up a Raspi, the sensors and a RRD data base and a graphical interface of displaying the results. The results are in the following pictures: