I’m getting an iphone for the first time this week and I am uninformed. Do any of the apps for lucid dreaming it carries wake you at the beginning of a REM period? Do any wake you at the end of a REM period?
thx
Well, I’m an Android user. I remember trying a lucid dreaming app, it was sensitive to any movements, speaking etc. And it would use that data to create a chart of my sleep pattern, then i would be able to set up some alarms according to the data.
I personally did not have much success with it. 
To answer your question, I would say it depends. It depends on your sleeping habit, and how heavy/light of a sleeper you are. Give it a try, results are different with everyone ~