I must be too old school because my first thought when i read this was “with an old solenoid lying around and a few lines of code, an AtTiny could strike a key on the bluetooth keyboard, waking the laptop!

starcraft, warcraft 2, warcraft 3, world of warcraft (up to lich king) descent 2, descent 3, halo CE, the original dayZ (the arma II mod), unreal tournament 2004 multiplayer maps, life is strange

have a look at Shelley smart devices. They have a wifi button that’s fully compatible with Home Assistant. Not the cheapest in the world but the quality is excellent. No Zigbee needed.

https://www.shelly.com/en

you might have to install OSMC in a proxmox virtual machine if you can’t do a bare metal install.

i’ve got one and hacked it with an ESP32. it’s awesome, but it’s not a CO2 sensor, it detects fine particles in the air.

do you have a gas meter? surely it would be simpler to capture the operation of the meter either electronically if it’s a smart meter or optically if it has a moving part or dial?

Even if your heating is gas it should be possible to disaggregate that usage by measuring the consumption over a minute or so.

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if you’re this concerned about the privacy of your doorbell camera then make your own solution with a raspberry pi. then you’re in full control of the device and data.

anything else can be updated to send video elsewhere, promise privacy features it doesn’t have, be bought out and shareholders demand data mining, or be hacked.

I can guarantee that if you drank pure petroleum and ate quicklime then you would spend the rest of your life without worrying about farts.