Glenn McKechnie <glenn.m...@gmail.com>: Mar 16 04:11PM +1100
Hi Clay,
The original UradMon A3 (https://www.uradmonitor.com/) had, along with
various other environment sensors, a gieger counter that registered in
cpm.
I've recently updated the driver
(https://github.com/glennmckechnie/weewx-uradmon) for it to return
microSieverts/hour rather than its default of cpm.
Rather than use the inbuilt group_radiation which defaults to W/m2 I
created group_ion_radiation (ionizing) and set cpm, micro_sievert as
its units (which probably should have been micro_sievert/hour -
Bugger).
That gave the flexibilty to enforce its unusual, but default, cpm
value; convert to micro_sievert/hour and keep it all self contained
(for the driver only). It also uses other units which are now in
weewx, but weren't when the driver was written. I've kept them for
backwards compatability.
https://github.com/glennmckechnie/weewx-uradmon/blob/master/bin/user/uradmon.py
--
Cheers
Glenn
rorpi - read only raspberry pi & various weewx addons
https://github.com/glennmckechnie |
"glenn.m...@gmail.com" <glenn.m...@gmail.com>: Mar 16 10:59PM -0700
I'll try again, it appears my first message failed to get through.
---------- Forwarded message ----------
[...]
Cc: weewx-development <weewx-de...@googlegroups.com>
Hi Clay,
The original UradMon A3 (https://www.uradmonitor.com/) had, along with
various other environment sensors, a gieger counter that registered in
cpm.
I've recently updated that driver
(https://github.com/glennmckechnie/weewx-uradmon) for it to return
microSieverts/hour rather than its default of cpm.
Rather than use the inbuilt group_radiation which defaults to W/m2 (as you
note); I
created group_ion_radiation (ionizing) and set cpm, micro_sievert_hour as
its units.
That gave the flexibilty to enforce its unusual, but default, cpm
value; convert to micro_sievert_hour and keep it all self contained
(for the driver only). It also uses other units which are now in
weewx, but weren't when the driver was written. I've kept them for
backwards compatability.
Link to the code follows.
https://github.com/glennmckechnie/weewx-uradmon/blob/master/bin/user/uradmon.py
|
"glenn.m...@gmail.com" <glenn.m...@gmail.com>: Mar 17 06:36PM -0700
The topic has advanced a little since my first post that went MIA. Now that
it has been released from group quarantine (Thanks Tom) I'll attempt to
add a little more to the discussion.
I've since updated the uradmon driver
<https://github.com/glennmckechnie/weewx-uradmon/blob/master/bin/user/uradmon.py>
to use micro_sievert_hour (as it should have been from the start)
The group is still group_ion_radiation - that's one for Tom to sort out, if
it makes it into weewx. It certainly can't be group_radiation as that's
taken.
I had a look at the mighty Ohm unit and it also appears to output cpm,
rather than micro_sievert_hour. A conversion is used in the original
tutorial
<https://mightyohm.com/blog/2012/02/tutorial-geiger-counter-data-logging/>
of approx 190:1 (up to 230:1 within the larger dataset given) to get to
micro_sievert_hour.
I then found a link to some perl software
<https://mightyohm.com/forum/viewtopic.php?f=15&t=3504&p=10357&hilit=cpm#p10357>
for the Mighty Ohm where a value of approx 175:1
<https://www.chankly.com/geiger/usv.html> (cpm * 0.0057) is used.
The original UradMon Kit1 unit <https://github.com/radhoo/uradmonitor_kit1/>
which is open source uses 158:1
<https://github.com/radhoo/uradmonitor_kit1/blob/master/code/geiger/detectors.cpp>
for the SBM-20 tube.
When I was adding micro_sieverts_hour to the uradmon driver I found it can
only be (as mentioned in previous posts) an approximation. There's a link
in the uradmon driver with a couple of references, one states that.
*'Note 2:*
*In the case of your updated question in the comments, technically there
isn't really a direct equation converting counts per minute (CPM) to
microsieverts because CPM is an electron count and microsieverts is a count
of bodily damage.'*
Which is a pretty good summary.
But that said, they still give a measure. Plus, whatever it is, we're after
a low value, whether that's in clicks or sieverts!
|
Glenn McKechnie <glenn.m...@gmail.com>: Mar 18 01:54PM +1100
Clay,
I've extracted the group_ion_radiation entries from the uRadMon driver
and copied them to /user/extensions.py (which itself is from
weewx-4.6.0)
If you save your copy and replace it with the attachment, then place
the following stanza wherever it's needed (under whatever skin you're
using in weewx.conf) then you should have working values for
micro_sieverts_hour in that skin.
[[[Units]]]
[[[[Groups]]]]
# Radiation options are 'cpm' or 'micro_sievert_hour'
group_ion_radiation = micro_sievert_hour
Anywhere else and they'll show up as cpm as that is the default under
that extensions.py example (because the uRadMon driver it was taken
from emits cpm)
Finally, change the weewx.units.conversionDict.update entries in
extensions.py to reflect your values (mine are 0.00909 & 110) and
you'll get the micro_sievert_hour value to suit your setup.
--
Cheers
Glenn
rorpi - read only raspberry pi & various weewx addons
https://github.com/glennmckechnie |
