I’m starting from tested and approved equipment, beginning with door/window sensors as well as the dongle you recommended here: Système anti-intrusion - #2 par pierre-gilles
I had also for some time Aqara temperature and humidity sensors that I had ordered to get started, but it just wasn’t the right time.
I just ordered motion sensors, two 90 dB alarms, a USB hub for my NAS to be able to plug in several dongles, a USB extension to bring the dongle out of my patch panel, Zigbee plugs for meshing across the floors.
With all that I plan to set up the anti-intrusion system, and monitoring of the different rooms in my house. I have an old Sony Z2 tablet that I plan to hang on the wall; I’m wondering about the power supply which won’t necessarily be easy to bring to where I want it, but we’ll manage. I also have a Sonos speaker which I’m looking forward to using via Gladys.
If all that works correctly, I’ll consider replacing my radiator valves and harmonizing the temperature everywhere — maybe cooler in the bedrooms — that would make sense, and then perhaps a few additional bulbs and plugs, but this is starting to add up!
If I do it I’ll have you proofread it anyway and yes of course if we can enrich it with an interview why not (FR and EN? 
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If I/we manage all that it’ll be pretty good, one step at a time. I’m not ruling out a video, but I don’t want to put the cart before the horse either 