gfroerli / firmware

Firmware for the water temperature sensor project
GNU General Public License v3.0
6 stars 1 forks source link

SHTC3 measurement mode #51

Closed dbrgn closed 4 years ago

dbrgn commented 4 years ago

Should we use the low power mode when measuring?

image

Since the temperature / humidity inside the enclosure are just "metadata", I'd say that yes, we should use the low power mode for all measurements.

rnestler commented 4 years ago

Should we use the low power mode when measuring?

It doesn't really matter, since we only measure once every 15 minutes. It's much more important that we put it to sleep afterwards.

dbrgn commented 4 years ago

It does matter, given that we do 35'040 measurements a year :slightly_smiling_face:

rnestler commented 4 years ago

It does matter, given that we do 35'040 measurements a year slightly_smiling_face

And we also do 35'040 LoRa transmissions which dwarf the SHTC3 power usage by orders of magnitude :wink: But if we'd do more measurements and only transmit significant changes, it would start to matter :slightly_smiling_face:

dbrgn commented 4 years ago

Ok, I think you're right, assuming my calculation is correct :slightly_smiling_face:

>>> uJ = (8.4-0.34)
>>> J_per_year = uJ * 35040 / 1000 / 1000
>>> V = 3.3
>>> mAh_per_year = J_per_year / (V * 3.6)
>>> mAh_per_year
0.023772929292929297 
dbrgn commented 4 years ago

Low power measurements seem to have an offset. Let's just stick to the regular measurements.