There was a bit of discussion around that: It Looks Like a School Bathroom Smoke Detector. It Could Be an Audio Bug (17 points, 4 months ago, 12 comments) https

There was a bit of discussion around that: It Looks Like a School Bathroom Smoke Detector. It Could Be an Audio Bug (17 points, 4 months ago, 12 comments) https://news.ycombinator.com/item?id=44915338 https://news.ycombinator.com/item?id=44915338