What would you recommend/what do people do for power and access for in-wall sensors? Pulling power at least once per room (assuming you can share at least 1 node with another room) and being able to access it if you need to reflash feel like hard problems.

OR, am I completely missing the point that it's "through walls", not necessarily in-wall (though that would work). A wall-wart-sized device containing the ESP32 board could be plugging in to each room and share the node (on the opposite wall) of the next room?

Very cool project and love the HA integration as well. I'm using PiR and mmWave (Z-Wave and Zigbee) currently but obviously you either have to run power for those or deal with replacing batteries, this seems much more maintainable and unobtrusive.

It's possible to have the devices in-wall, but it might not be that practical as you point out. Or at least they would have to be taken out once for flashing, then OTA updates would reduce or eliminate the need for reflashing further.

The real benefit from the sensors working through walls in my opinion is to be able to hide the devices away (e.g. in a closet or drawer) + being able to create zones that crosses walls. Image wanting a zone called 'upstairs', 'downstairs', 'garage' etc. which consists of multiple rooms divided by walls. Instead of having a sensor in each room you might just need one on each side of the total area.

Thanks! I agree with the PiR and mmWave limitations. Right now I think this project can replace motion sensor. Hopefully mmWave when stationary presence detection is added (planned Q1 2026).