the app called Sleep routine has around 70% accuracy at sleep tracking but is dirt cheap and privacy respecting
the app called Sleep routine has around 70% accuracy at sleep tracking but is dirt cheap and privacy respecting
In this study the app called sleep routine was compared against 11 other devices ranging from what they are categorizing as wearable, nearable, and airable, the devices are all a little old now but the data for the app is still relevant, it matches the accuracy of my pixel watch 3 based on the testing I have been doing on and off for awhile.
As far as I can tell it does something with spectrum analysis from the microphone and gets more accurate as time goes on I'm not sure on the specifics but the app seems like its decent on the privacy respecting side of things and comes from a country that has decent laws on that stuff so its probably fine.
Some recommendations for the app, keep it close to your head for cleaner audio signals, cross check the app with any sleep tracking devices you may have just as a comparison test, focus on how they compare over time and not so much night to night because unless you have a really solid routine for sleeping each night is going to be a little different and hard to tell what is a result that changed because of the app.
Highly recommend giving the app a shot since it is inexpensive and super worth it if you spend a little time improving your sleep,technically you should only need the app for a month or two before you get a solid idea about your sleep quality so that you may change your habits and not necessarily need to keep tracking your sleep.