Re: Pressure sensors

[Artturi Alm <artturi.alm%gmail.com@localhost>]

On Tue, Jan 01, 2019 at 12:03:31PM -0500, Greg Troxel wrote:
> Artturi Alm <artturi.alm%gmail.com@localhost> writes:
> 
> > my sensor does fill ->value_cur with mPa, so pressure does fit into the
> > "everything else"-else{} with ->cur_value / 1000000.0 for printout in kPa.
> 
> Until very recently I had never seen pressure in kPa.  For atmospheric
> pressure, the standard unit seems to be hPa.  I realize that's a
> less-normal SI prefix, but it happens to match mbar.  But, I am seeing
> kPa more tha last 6 months.
> 
> So, I wonder why you are choosing kPa vs hPa, and if that choice ends 
> up being a framework choice for everything.  And how the rest of the
> world deals with this issue.
> 

By accident, i guess, and after having read about pascals on wiki[0],
it felt like a good choice, for being "not just for meteorologists",
nor imperial, but i'm from metric .eu, fwiw..

I actually got *= 1000 for mPa in the driver, so i don't really care
about the unit to be used, as long as it's not loosing any precision/
limiting range (for kernel -> user, so Pa would work just as well, and
i'm not sure whether mPa does buy anything w/r.t. future sensors, it
was more about minimal diff looking reasonable).

-Artturi

[0] https://en.wikipedia.org/wiki/Pascal_(unit)