op I was trying to show your theory that all is the same was a folly. You obviously know better and I'm wrong. Sorry I said anything that you don't agree with. Btw how did your a.n.other 868 work?
I was thinking about how they work, am might be part of it but am isn't anything to do with how they detect movement, well not at more than a few cm
I've just reread yes it probably is that basic
im assuming this is about the difference between dual edge and quad edge elements. Can't see its logic vs pulse count. You could go leftfield and add alarmcom fuzzy logic ir220 into it