Luftdaten Air Quality

Hi
I have now changed the temp/humidity sensor for a BME280 and the humidity looks much more sensible.
Brian - is there any way of deleting erroneous luftdaten readings. While testing the new sensor I got some very high readings (I really should give up my cigars).
Regards
Alan

Hi Brian
Sorry I missed the download.
I installed the zip of the new exe etc and the new boxes were there. I’m not sure if the BME280 has a separate id (it does as far as Luftdaten is concerned) or I have not found it yet. There is no clue in airquality2.txt . I do have indoor temp / humidity so I guess it does need the override.
Best wishes for Christmas and the New Year
Alan

I’m using the SDS011 sensor connected to my RPi and then to WD. It’s not the “official” Luftdaten package). What I’m seeing is that sometimes the values are relatively high. It’s interesting how the values change, as shown in attached figure. It drops almost discretely just after 2:32 and then also around 5:00. Has anyone observed such behaviour? The air is calm, no winds, but just high humidity over several days already. It’s few degrees above 0 degC so not freezing.
Is it possible high humidity causes such response?


aqichart.gif

Hi
I understand it is a known problem with high humidities. It seems particularly bad (no pun intended) in foggy situations.
My system has shown some enormous figures (400-500 on PM10) which are quite unrealistic for a small rural hamlet about 8K from the nearest (small) town.
I have tried inserting a strip of hard polystyrene into the air tube. The idea is that the surface is supposed to be hygroscopic (not absorbing but attracting) so that water particles might condense. It does not appear to work.
I think the Luftdaten team are trying to find an algorithm to compensate.
Incidentally the BME280 temp/humid sensor is so far performing much better than the SHT22 which stuck at 99.90%.
regards
Alan

I should have said DHT22 9I’m looking at the SHT series for something else
Alan

I don’t know what you mean by BME280 - is this sensor used with the SDS011? I have one connected nearby and could correct the PM values but would need to know the correction algorithm. Maybe the sensor needs just a little heating?

High RH is rare here but we have had a couple of fine rain or foggy days recently with the RH sitting in the very high 90’s. I have not seen the extreme particulate values that previous posts have suggested. My sensor is a PM-5003 connected wirelessly to a linux PC. There is some elevation of particulate values but I would expect that with the concurrent stagnant air conditions here at the end of the valley which trap woodfire smoke and other pollution.

I think it is the SDS011 that is mainly affected. In answer to Mihec the BME280 is an alternative T/H (and pressure) sensor. On opensensemap a lot of the humidity readings are stuck at 99.90% which is what my previous DHT22 t/h sensor always showed. If you use the T/H option I would recommend the BME sensor.
My site is at the far south western tip of the UK with very few pollution sources between me and the North Atlantic. With a west wind of about 10 knots currently I would expect quite low particle counts but actually they are all over the place so I strongly suspect the present fine particle fog we have. You can see what I mean on the Luftdaten map site. If the wind is in the right quarter (and light) I can pretty well tell when my neighbours light their woodburners. The SDS011 may not be the most accurate but is affordable and simple enough to allow a lot of users to participate so it is enough to show general pollution trends over a wide area.
Regards
Alan

In the last half hour it has started raining and cleared to fog - reading now more normal - does rather confirm the fog affect. You can also see what I mean on my site www.greatbosullow.net
Alan

That’s very interesting, on my sensor I don’t believe I have ever seen such a huge difference between PM 10 and the others 8O

Strangely a couple stations in the far west of France and another UK station to the NW of me sometimes show high readings with a west wind - with the proximity to the Atlantic I wonder if the humidity can contain dissolved salt.
Alan

I used to live on the pacific coast and the fog there certainly had salt content.

After few days observation I think the fan is not rotating. Is there any diagnostics (apart from my ear) to tell if it

I think the fan only runs when it is taking readings but I can’t really check as my sensors are quite high up a wall.
And Brian - I would like to use the luftdaten temperature and humidity but the wmr300 produces the indoor values so I guess I need the override. Looking at airquality2.txt the values for TH are there with the sensor described as BME280 as attached.
Best wishes
for 2019
Alan


airquality2.txt (469 Bytes)

Copied from luftdaten FAQ.

Der von uns verwendete Sensor SDS011 hat laut Datenblatt eine Lebensdauer im Dauerbetrieb von ca. 8.000 Stunden. [b]Unsere Firmware schaltet deshalb den Sensor nur f

What firmware are you guys at.
I have set to update automatically.
I think I got a new one last week, had to pull the powerplug to get it going again.

Firmware-version: NRZ-2018-123B

Hi - Yes the firmware is the same NRZ-2018-123B. I have had occasional re-starts - not sure why but I’ve only had to pull the plug once and that was to get the sensor back on the network.
Alan

And Brian - I would like to use the luftdaten temperature and humidity but the wmr300 produces the indoor values so I guess I need the override. Looking at airquality2.txt the values for TH are there with the sensor described as BME280 as attached. Best wishes for 2019 Alan

there should be a airquality3.txt file?
I will need to add override for wmr300 data

[quote author=Weerstation link=topic=67338.msg541485#msg541485 date=1546096434]
Copied from luftdaten FAQ.

Der von uns verwendete Sensor SDS011 hat laut Datenblatt eine Lebensdauer im Dauerbetrieb von ca. 8.000 Stunden. [b]Unsere Firmware schaltet deshalb den Sensor nur f

Thanks Brian
The only files I see in wdisplay are airqualityaqi.inf and airquality2.txt
Alan