For teenagers, presence detection is accurately performed by bluetooth as they are never, ever separated from their cellphones.

SirHumphreyAppleby:

 

reven:

 

just need a way to accurately detect room occupancy when there's no movement.    this is a cheap reliable way of doing that

 

 

I got myself one of these to play with https://www.aliexpress.com/item/1005004351593073.html

 

My main reason for going down this route is it will simply output to a pin when human presence detected, and you can programme the sensitivity based on ranges. Unfortunately, while the no motion sensing seems to work, it doesn't trigger the output like motion does, so you need a device that can interpret the serial data.

 

nice.  may get some of these. 

hardest room I have to detect right now is dining room.   when sitting around board gaming, not a lot of motion, dont think motion sensors will work well here, well not alone.  where this sensor might. 

was going to get a sensor from https://shop.everythingsmart.io/collections/everything-presence-one but stock issues

I dread to think what you have planned for the smallest room of the house.

reven:

 

hardest room I have to detect right now is dining room.   when sitting around board gaming, not a lot of motion, dont think motion sensors will work well here, well not alone.  where this sensor might. 

 

was going to get a sensor from https://shop.everythingsmart.io/collections/everything-presence-one but stock issues

 

Vibration sensor stuck to the table, maybe?

thats not a bad idea actually, worth looking into.  thanks