Used originally because of ease of access, pre-chip shortage. Used, decommissioned thin clients are an alternative currently being tested.
As many PIR sensors have motion buffers that are longer than pratically useful for many potential YERP! installs, this sensor was selected on account of its "test mode" dipswitch, with a five second motion buffer. Battery life is still excellent in test mode, lasting around 18 months.
These are certainly a lot more economical than the Ecolink sensors but require fabrication, along with printing up a case and wall power.
Not much to say about these, they were picked for ease of access and work fine!
Under early development for using this wall switch panel as an interactive console. Working on this thing is a whole can of worms in and of itself, and may need to wait until other Home Assistant hackers put something together more extensible than the current offerings.
Researched and tested for potential use as a device that can directly monitor respiration over the air via radar. Which it can! But unfortunately, respiration detection only shows readings after a subject has already been still for around 30 seconds.. probably pretty useful for monitoring breath rate while sleeping, not that useful for this project (and at $250 per sensor, more expensive than some other builds top to bottom).
Used as a webcam for the demo install. (Actual installations don't include any audio or video recording)