I finally got my hands on an old Wild Divine LightStone. And finally managed to keep the finger clip on all night after many attempts. I also wore the halograph FM and the heartbeats as measured by the IR sensor from the finger and the accelerometer in the headband line up perfectly. 63 beats can be seen in the minute above.
Encouraged by the findings of Masao Yaso, Atsuo Nuruki, Sei-ichi Tsujimura and Kazutomo Yunokuchi, I have started working on an algorithm to detect REM sleep from the pulse…