Measurement Sleepphase

Source [1] is a app which measures the sleep cycle. This app can measure your sleep phase on two manners. The first one is with a microphone. Your smartphone determines on basis of the sound you produce during your sleep in which sleep phase you are. You’ve to place your phone like this:

The second manner is with an accelerator. Now, your smartphone determines on basis of your movements during the sleep in which sleep phase you are. You’ve to place your phone like this:

Calibration

Sometimes, you need to calibrate your smartphone one or two nights. This, because the microphone or accelerometer will be to sensitive. For example, you don’t only measure your movements or sounds, but also the vibrations and sound of a passing truck.

Sleeping with two persons

On their site, they claim that it also works when you’re sleeping together in one bed. This, because sound decays exponentially with distance. So the sound generated by your partner will have a much lower volume than sounds generated by you. The app communicates also over Wi-Fi with the device of your partner. This makes it possible to detect where in bed a sound originates from with an accuracy of 30 cm.

Correctness of measurements

To be sure these measurements are correct, it would be nice to have some evidence. So I’ve sent a mail to the company of the Sleep Cycle app. I hope they could give us some evidence. (I’ve also sent the mail to two other apps who do the same thing.

Sources (three App’s)

[1] Sleep Cycle(App), How does it works, http://www.sleepcycle.com/howitworks.html

[2] Pillow2.0 (App), https://neybox.com/pillow/

[3] [7] Azumio, Sleep Time (app), http://support.azumio.com/customer/en/portal/topics/667008-sleep-time/articles