I have a couple of motivators, one of which is to improve occupancy sensing for the in-building element of our IoT Launchpad project, as well as OpenTRV.
In any case, the simple heuristic that seemed to give the best fit, eg no false positives in holiday time, and mainly plausible times for other occupancy detection, eg as cross-checked with time of day and my diary, was that quickly rising RH% (>2%/h) suggest occupancy.
I have added a few lines of code to that unit to add that heuristic to the existing ones, to see how things improve or otherwise.
ST: thanks in particular to your observations of the correlation of RH% with CO2 with occupancy.
PS. The all-in-one valve units that we are finally tooling up for include RH% sensors, as do the simple in-building sensor units that we are just kicking off.
Edited by DamonHD, 01 November 2015 - 10:42 AM.