How about if I want to monitor the apartment as a whole? Would 100m2 be too much for one sensor to handle?

It really depends on the environment: wall materials, interference, signal strength, and even temperature and humidity all play a role. Honestly, 100 m² is probably too large for a single sensor to cover reliably.

That said, ESP32 boards are very inexpensive, you can find them online for around €1 or even less.

▲

yoavm 7 hours ago | parent [-]

Is the ESP-S3 your recommendation? Or should one look into the ESP-C6 / another model? The prices I'm seeing here in Sweden are more around €10 rather than €1, but I guess that's still much less than the average presence detector.

	▲	francescopace 6 hours ago \| parent [-]
		The price difference can vary wildly by region, but €10 is still super cheap compared to a dedicated presence sensor! Regarding the chip recommendation, it’s a classic trade-off: ESP32-S3: This is what I mainly recommend today. It gives you more raw processing power (dual-core), which is great for managing the OS, MQTT, and the CSI analysis without hiccups. ESP32-C6: I just ordered a C6 myself to run extensive tests! The C6 might have a superior quality Wi-Fi module and better internal CSI extraction capabilities due to hardware improvements.