Accuracy: Phaser vs Smartwatch vs Sonar

What is the relative accuracy of the various methods of recording sleep (i.e. Phaser vs. smartwatch vs. sonar)? I am willing to invest a bit of money in a system that will accurately measure my sleep, but I do not know which is most accurate. I am also interested in the relative accuracy of each to assess cost/benefit - I am willing to pay $89 for the Phaser if it is 50% more accurate than the other two options but not if it is only 5% more accurate. Obviously, there are many variables that make quantifying this difficult, but even an educated guess would be appreciated.



Smartwatch would be always the most precise since there is a direct conversion of your limbs’ movements to the sensor’s data.

Comparison with other methods:

  • phone’s accelerometer is fine too, but there is of course the issue of comfort (having the phone in bed) and the firmness of your mattress plays a definite role
  • sonar is really good and comfortable, but behaves erratically on some phone models, especially noname China, but on some high ends as well (due mainly to unpredictable hardware or firmware DSP in front of the sonar)
  • Sleep Phaser did not yet come through the real field testing (the first batch was shipped a few weeks ago) but we know of one shortcoming of the Phaser - as it’s sensor is based on infrared detection, it’s readings can be distorted by thermal fluctuations in the room (like a window wide open or if you have a heater next to the Sleep Phaser)

I cannot really give out numbers on a linear scale to show which method is better, maybe a polar graph would be more fitting - but anyway, I believe that choosing a sleep monitoring method is not just a thing of numbers, but of assessing comfort as well.

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I am definitely interested in seeing how the sleep phaser does. I just started using a wearable last night and am trying to determine how accurate it is. The graph is wildly different than what I got using sonar.

I have tried a smartwatch and a Miband (via Miband tools) and the smartwatch (moto 360) was the best option, since it did detect my movements quite accurately. The problem with that was that moto 360 is quite large and is not very comfortable… If only fitbit was compatible… I think we’d have a very good option here :frowning:

We might have something cooking…

What happens if you use multiple sources in the app? Does it just average them? For example, enabling both accelerometer and Wearable.

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