Thank you for this, I have read through the thread with interest and havre replicated the “Timers Version” and it works, which as a newbie I am pleased with 
Could you explain the line:
if(occupancyTimer === null || occupanctTimer.hasTerminated()) {
as a beginner I struggle to find places to look up the syntax?
I assume “===” means does not equal?
What do the “||” characters mean?
and one final question, I thought occupanctTimer was a typo, but as it works, it is obviously not a typo, it is only referenced here and does not get reused, can you explain this in a little more detail please?
Sorry for all the questions, I’m finding OpenHab a steep learning curve
Ian