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[Feature Request] Flow Rate graph to Audio File?
#1
[Feature Request] Flow Rate graph to Audio File?
Hi all. Thanks for the great work on OSCAR.

After going over many flow rate graphs, I had the idea that being able to HEAR what the graph is showing (even if the audio is computer generated) would make it a lot easier to interpret/compare to your actual experience of sleeping that night.

I'm no developer so I don't know how complicated or easy this would be, but I feel like it would be a valuable feature for anyone who isn't a sleep analysis expert.

Example use case:

I know what my breathing sounds like when I'm awake, but it would be nice to also be able from oscar to hear what it sounds like when I'm asleep. It would help me identify where I'm actually asleep/waking up on the flow rate chart without having to memorize patterns and zoom to incredibly close intervals to tell them apart. Or it would help me understand what the body is doing when I see a big spike upwards/downwards in flow rate, and see if I can remember doing that in the night.

etc

Thoughs?
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#2
Cool 
RE: [Feature Request] Flow Rate graph to Audio File?
One way to get that would be to use the flow data as an envelope to modulate the volume level of a pseudo-breathing sound (eg pink noise). That could be done in code but (as I only just now discovered), it is more easily/accessibly achievable via the free audio editing app Audacity.

I tried it first using a generated sine wave (1 Hz) modulating a generated pink-noise signal.
However, to achieve your goal...

The rough steps are:
* From your CPAP / OSCAR / flow data app, export the relevant data (eg as CSV)
* Using eg a spreadsheet if needed, ensure the data is in the expected format (only one column, no header-row, no rubbish values, normalised to be in the range -1.0 to +1.0)
* In Audacity...
* File > Import Raw Data) --> a new mono audio track (but don't bother trying to play it).
* In that track's header (at its left side), balance-control adjust it to full-left.
* Generate pink noise (say) to a new track (below it), balance-control adjust that to full-right.
* Combine the two tracks into one stereo track.
* Apply the in-built Vocoder effect.

Vocoder effect lets the left-channel signal (eg flow data) modulate the right-channel signal (eg pink noise)
(it actually multiplies the left and right channels by each other, so really it is egalitarian)
The result (modulated pink noise) appears in both the left and right channels.

YT Tutorial Vidos:
* Vocoder Effect - Quick Demo - https://www.youtube.com/watch?v=Mp5XI_jqDHE
* Vocoder Effect - Documentation - https://manual.audacityteam.org/man/vocoder.html

PS (Geek-Mode):
If you really want to hear beyond/below human hearing range data (eg the modulating flow data by itself) then you'll need to use something like Audacity's Change Speed... Effect (which is like changing speed of a tape recorder or gramophone record)

When I did that for my pulse rate data, it gave a tone (which I guess is the sampling rate) and some scratchy sounds (which I guess is the pulse rate variation). Not useful, just had to be tried!
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