[tobyportugal]

Hello,

I think that several people here received e-mail for a AQI Purpleair.
https://www.purpleair.com/?utm_source=WU...PWS_Owners
[/url]https://www.purpleair.com/map?&zoom=3&lat=45.83957015303712&lng=-14.365157432556154&clustersize=30&orderby=L&latr=79.86901084421095&lngr=236.25000000000006

They use a sensor PMS5003 and Arduino system
https://www.purpleair.com/technology
http://aqicn.org/sensor/

I made a research, and I found a document interesting
http://www.aqmd.gov/docs/default-source/aq-spec/field-evaluations/purple-air-pa-ii---field-evaluation.pdf?sfvrsn=2
[url=http://www.aqmd.gov/docs/default-source/aq-spec/field-evaluations/purple-air-pa-ii---field-evaluation.pdf?sfvrsn=2]
Measurements are rather reliable.
They use THINGSPEAK.COM, the data are easily recoverable.
I would be curious to compare at my Sharp.

If I were certain that Portuguese customs…. Bad recent experiment…   
I would be therefore for a comparative test AQI (PurpleAir/mine/WearherDuino), a good means to refine the AQI WearherDuino.

Good day

[werk_ag]

I would be therefore for a comparative test AQI (PurpleAir/mine/WearherDuino), a good means to refine the AQI WearherDuino.

That is you supposing, that the one who may need to be refined is the WeatherDuino AQM.  
We are working in the AQM for almost a year, testing it and comparing results in an hourly base with a nearest official AQICN station which is also not very far from you.
At this precise moment the official station in showing a AQ Index of 34, and our is reading a value of 36!

The WeatherDuino AQM will also use a sensor made by Plantower, but it will be a more recent and more precise version than the one used in the purpleAir unit. Optionally, our Air Quality Monitor could also use a SHARP sensor. I don't know which sensor are you using, but I would like to know, specially which hardware is used. A custom system? Arduino based? You wrote the code?

[tobyportugal]

Can I answer in French?
In English/Portuguese it is too difficult for me and I think that my translation will be incomprehensible.

If French or Luxemburgish who is here can make the translation?

If that does not go, I will test in English.

Merci

[zitoune]

Can I answer in French?
In English/Portuguese it is too difficult for me and I think that my translation will be incomprehensible.

If French or Luxemburgish who is here can make the translation?

If that does not go, I will test in English.

Merci

I can in French

[werk_ag]

Can I answer in French?

If you reply in French, will be me that will not understand   .
I think that is preferable do not mix languages, it will be confusing for the majority of the users.

Bellow is an automatic translation using Google translator, I think it does a good job translating from (my poor) English to French, have you tried from French to English?


Vous trouverez ci-dessous une traduction automatique à l'aide du traducteur google, je pense que ça fait un bon travail en traduisant de (mon pauvre) l'anglais au français, avez-vous essayé du français vers l'anglais?

Si vous répondez en français, ce sera moi qui ne comprendra pas   .
Je pense qu'il est préférable de ne pas mélanger les langues, ce sera déroutant pour la majorité des utilisateurs.

[tobyportugal]

Ok, but it is paramount not to forget that to think/write “A” in French can become “B” in english.
In French that requires 5min, in English 5h… thus patience

[tobyportugal]

Hello,

I think that to make a comparison with a station which is +/- 35 km is rather hazardous.
Yesterday, with 35km W of Cercal the Lourinha station had 34AQI, with 60km E of Cercal the station of Chamusca had 42AQI.
If one compiles data of AQI.ORG and PurpleAir: for example in Chandigarh (India) the two networks have a station with +/- 10km.
http://aqicn.org/city/india/panchkula/se...chkula/fr/
https://www.purpleair.com/map?&zoom=8&la...4287109375

The differences are large.

The temperatures, the direction of the winds, the reactivity of the sensor, the ventilation of the sensor can distort calculations. It should not be forgotten that standards AQI it is a measurement doubts the hours (table 1) and an average during the last hour (table 2).

https://thingspeak.com/channels/182605/c...&type=line
https://thingspeak.com/channels/182605/c...&type=line

When I measure a AQI with my detector, it is impossible (without instruments of laboratory) to be certain at 100% of measurement.


 
On the graph how to be certain that the curve punt is not a bad ventilation or a saturation.
It is as the probe of t° NETATMO which is a true filth (overheating) but when one places probe NETATMO in a shelter DAVIS 7714, measurements are very close to a VP2.
Thus I think that it is necessary to make statements on a single place/environment.

If one assembles comparative on the same place with my detector + WeatherDuino, everyone would be winner.
My remark on the PurpleAir detector is simple: according to my Internet searches produces it is well conceived and was testè in a scientific environment.
We thus have a point of reference (+/- correct) and as it is a Arduino base…
But with the Portuguese customs, I do not want to pass by the case.
The finality of the my WeatherDuino future is the comparison of the various solutions.
This evening I will post photo information/my detector.
 
PS: I have emmerdeur (in french ) … to obsess by the precision… that irritates my wife for 35 years

[hornychz]

Hi,

Only one note from me:

we are living in a house in a garden. And when I measure AQI in front of the house (street and sidewalk)
I got completely different values than measured 10 m far in the garden ...

[tobyportugal]

Good evening,

My detector AQI was made by a French friend electronics engineer which lives in China.
The PCB is a derivative of a PCB which made for solar cam 100% autonomous.
That which is at home: http://www.solarcamlab.com/webcam70/webcam70.htm
Laurent a very great control of the energy management.
I made a test of autonomy on my cam without solar energy (only on its battery) at the end of one month I still had autonomy!
One has needs also an autonomous repeater solar WIFI 100%, it arrives in test at home in September (with the Chinese clouds…)
(for my station Blitzortung)



It made other things design/fun.
It is not the subject which worry us, but it is simply for you show that Laurent is not a handyman of Sunday.
All that Laurent does passes by the management of solar energy/battery, but lack sometimes of a rigorous approach of measurements and their exploitations.
It is what I try to bring to him according to my weak competences. .

Version 1 is at his place in China, but it does not respect standards AQI completely.
https://thingspeak.com/channels/49795
It made for me a version 2 (not “clean” prototype) respecting standards AQI, the PCB is derived from its cam,
the sensor is Sharp GP2Y1010AU.



https://thingspeak.com/channels/182605
In appendix characteristics of the SHARP.

In 2016, in fact the SHARP was more the energy saver (always the goal energy of Laurent) reason of the choice of the SHARP.
My detector set out again at Laurent, one reflected to replace the SHARP by another.
I prefer to keep the SHARP which has autonomy of use definitely larger than the PMS (less than 3 years! laser!!!).
According to Laurent Plantower is not the originator (for the sensor part) of the PMS.
When I will recover my detector, I will work on his “mechanical” assembly
(in this field I am not likely to make stupidities) with a shelter Davis 7714.
That will allow better a natural ventilation as well as a clean and functional assembly.
The code is made by Laurent, as he says it is hard, but that goes.
I do not touch there - > one will see after the adventure of the RX/TX.
Unfortunately Laurent is far from available, therefore the evolutions are slow.

I hope that you understood me and seized the goal of my approach: to compare to evolve.
Good evening with all.

PS: "Oufti" like one says in Belgium, maintaining a good beer Belgian and good Belgian chocolate

[tobyportugal]

Hello,

Here a study on Sharp (Not bad this sensor)
http://www.tandfonline.com/doi/pdf/10.10...15.1100710

For information:
http://aqicn.org/sensor/pms5003-7003/

Good weekend