[time-nuts] BME280 board.

Poul-Henning Kamp phk at phk.freebsd.dk
Wed Oct 9 20:49:03 UTC 2019


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In message <b87b323b-2d8a-d33a-ae7d-43b6bc472ad3 at irtelemetrics.com>, Dan Kemppa
inen writes:

>The idea WAS to build a temp/pressure/humidity logger for time nuts use. 

I'm playing with a couple of these right now:

	https://www.te.com/usa-en/products/sensors/multi-sensor-modules.html

and they seem to work fine, and delivers a good set of sensors for
a good price.

The one footnote I have is the so-called "eCO2" measurement.

What really goes on is that they measure VOCs, "Volatile Organic Compounds"
and have some magic formula to convert from "measured VOC" to "probable
if CO2 if all these VOCs came from people in a room".

The actual sensor is CS811B, and they're not exactly making a big deal
about this in the data-sheet.

Their algoritm may work for rooms like classrooms etc, but at least
in my one-man office, this part of the board is essentially a
fart-sensor.

But the temp/humidity/light/battery voltage part works great.

Havn't played with the motion detector, and didn't buy the
microphone option.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.




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