7
Google "Nest Detect" sensors
(lemmy.world)
Home Assistant is open source home automation that puts local control and privacy first. Powered by a worldwide community of tinkerers and DIY enthusiasts. Perfect to run on a Raspberry Pi or a local server. Available for free at home-assistant.io
Homebridge might be worth a shot. I know its Nest integration is better in some ways than HA's native integration.