I suspect these are simple bluetooth low energy beacons. Will find out more on my next visit. I have to wonder about the cost-benefit of these. It seems like you should already have a regular schedule for cleaning. So that leaves out-of-band events. Seems like a sign with a phone number for call/text would have worked as well...
... or Amazon Dash for cleanups.
Paul Lindner, Aug 18 2016 on 1500wordmtu.com