Hello,
Would it be possible to use RuuviTag as sleep tracker? I’m not fan of sleeping with phone (I don’t have any smart bands/watches) and hiding RuuviTag in mattress would be so easy. RuuviTag is open-source wireless sensor node with accelerometer, temperature, relative air humidity and air pressure sensors. I dont’t know anything about software but open-source+bluetooth+sensor sounds like it would be (quite easily) possible.
BR,
iheilala