Should "time correction" be optional (for those who have set a "time offset" in SleepHQ)?

[ilyakruchinin]

It has come to my knowledge that some people are using the "time offset" configuration in SleepHQ (to align their EDF data to pulse oximeter readings).

I'm wondering if what's going to happen once people start using SomnoTrace, which has perfect NTP-based timestamps?

Because they would need to set the "time offset" to zero (0). And that might make SleepHQ display their historical data (imported before using perfectly-timed SomnoTrace) with the drifted timestamps from the AS-generated EDF files.....

[ilyakruchinin]

The answer (potentially) lies in understanding how SleepHQ applies the offset.
Looks like they have a per-day setting (only applies to the exact day):

[ilyakruchinin]

Question to people using the "time offset" feature on SleepHQ web site.
Do you have to edit this setting daily (per each day)?

Or is this something you set "for today" and it stays there for all days (global)?

I did some research/trial, but I find their implementation extremely confusing.

[ilyakruchinin]

I went ahead and changed it a few times for a few days, and found that it "sticks" to a single noon-day only.
So looks like it's a per-day setting in SleepHQ. I couldn't find any "global" setting that would automatically apply to new data.

[cdbrow]

I enabled the ability to upload to SleepHQ and did a quick session with it. I did not make a change to the existing offset of -3619 at the device level in SleepHQ. The session that showed up was exactly 1 hour and 19 seconds behind. So I went in and changed the device offset and set it to 0. It did not change the offset of previous sessions/days. I then changed the offset of today to 0 and the session looks accurate. I'll now try to enable the ring at the exact same time as starting a session and confirm that they line up. Thank you!

[ilyakruchinin]

I cannot find the interface to set it for a device (not just a day)

[cdbrow]

I cannot find the interface to set it for a device (not just a day)

If you are in the Web interface, click on "Devices & Accessories", then click on "Details". If you are in the app on your phone, it is similar. Go to "More (the 3 dots)", then "Devices & Accessories", then click on "Details".

[ilyakruchinin]

Found it, thank you!

[ilyakruchinin]

I'll look into the Ring in due course, but if you have it paired to your phone, then the timestamp should be accurate.

Please note that when you "start" the session (for example by pressing a button on AS11), the EDF files are not recorded straight away (there is a delay of a few seconds).

If you want to test the timestamps - the best approach is to open https://time.now/clock/ and at a specific chosen time do a "quick breaths in/out, then hold your breath" to "mark" the moment/second (and then compare).
This test has been done before in #16 and was successful (perfect timestamps).

[ilyakruchinin]

Turns out there is another interface for Machine setting (with the time offset applied globally to the machine).
Not sure how it works, but @cdbrow is doing some testing now (I will do, too).

[ilyakruchinin]

So far it kind of seems like the following is true:

• Devices and Accessories

  • Machine Settings
    • Edit Machine
      • Time Offset
        This does NOT affect the previously imported sessions (seems to only be applied at import time for new days).

• Dashboard

  • Choose day -> Three dots
    • Edit Session Times
      • Time Offset
        This ONLY affects the single day it's set to.

In summary, that would mean that users will simply need to update the Machine Settings and from there on the time-corrected EDFs from SomnoTrace will be perfectly synced (without any issues affecting the previously recorded data).

[ilyakruchinin]

Does the above look correct @cdbrow ?

[cdbrow]

Yes, that is accurate! I have also confirmed that it lines up with the time from my ring, which I manually upload to sleepHQ. I did the test where I read quickly, then held my breath, then continue to breathing. I actually did that twice. It lined up perfectly with the time website.

[cdbrow]

It’s about my bedtime, so I will do a full test tonight with both the ring and the automatic upload. I suspect it will work just fine, thank you. It’ll certainly be great when we have the ring connected as well.

[ilyakruchinin]

Thank you so much for your time and testing! Highly appreciated!!!

[ilyakruchinin]

This has proven to be very important to understand the correction mechanism that SleepHQ uses.
But this is no longer relevant as we have all the answers.
I'm closing the discussion. Relevant information will be included in the README instructions when the source code is released.
Thank you all for your input.