The problem with smartphone apps is that they can only measure vibration and sound. Vibration can be used to see how much you move around and sound can get to the breathing frequency.
As Gunnar already said, vibration + breathing frequency doesn't seem to be a perfect way to measure sleep stages. The heart rate provides for better data. It would be interesting to know how fine the bed can track heart rate. If it could track HRV it would be really great.
The mattress on the other hand can measure the heart rate. At least they claim so on the website. Unfortunately the website is quite poor at providing information about the technological capabilites of the product.
Aren't there wrist devices that can measure your heart rate over time? Not sure how well they work, but they might be cheaper than a gadget bed.
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