Davide Gironi
i'm working on the Samyoung DSM501 dust sensor.
I would like to share my results with you, and ask you if someone has used this sensor too.
This sensor works like the Shinyei PPD42NS.
To get particle values > 1um, i read low ratio from output Vout2 (look at the datasheet).
To convert it to something usefull, this function.
concentration_pcs283ml = 0.02791 * ratio2^2 + 614.1*ratio2 + 4.926
This function is derivated doing polinomial fit from the low ratio vs particle (pcs/283ml) graph you can find in the datasheet.
There is another interesting graph in datasheet, that let use correlate low ratio to ug/m^3.
The derivated function is:
concentration_mgm3 = 0.001915 * ratio1^2 + 0.09522 * ratio1 - 0.04884
I use the same functions read above to convert value read from the Vout1, with control pin open (no connection), which should be for particles > 2.5um.
Now the questions:
0) do you see something wrong in what i've done above?
1) I - actually - don't have any instrument to correlate the value i read to PM1 or PM2.5 real values. Do you have instruments to do this?
2) If i substract concentration_mgm3-forVout1 to concentration_mgm3-forVout2 i should find particles with diameter between 1um and 2.5um, so i can find PM25 particles, right?
Attached my matlab helpers to build the polinomial function.
Michael Heimbinder
http://www.takingspace.org/make-your-own-aircasting-particle-monitor/
http://www.takingspace.org/more-aircasting-air-quality-monitors/
http://www.takingspace.org/my-air-my-health-challenge-update/
-Michael-
Davide Gironi
the Michael Taylor algorithm for reduce the noisiness of the measurements is interesting, and the regression for the dataram particulate monitor too
also the breakdown of the PPD42NS (http://takingspace.org/wp-content/uploads/ShinyeiPPD42NS_Deconstruction_TracyAllen.pdf)
i will now ask Michael Taylor more info about the DSM501A, cause it would like to correlate (if possible) DSM501A reading with some particulate (PM1 or PM2.5 or other)
Matteo Mortari
Davide Gironi
Ciao Davide, just to kindly ask if you had any success in correlating the DSM501 with PM2.5 indexes, please? Thanks;
nothing, couse i do not have anything to correlate with :-/
i'm waiting for "Michael Taylor" to replay me for the correlation he found.
his experiment here:
http://www.takingspace.org/wp-content/uploads/MAMHSolutionNarrative-HabitatMap+NYU+CMU.pdf
and the moving average alghoritm here:
https://github.com/JSchapiro/AirGo
very interesting
note the regression y = 0.0984x + 94.656x information to correlat e DSM501 reading to DataRAM and ug/m^3?
Micheal write me some month ago telling that wen he has time he will send me further information, but at now nothing is sent.
If you have further information please write to me.
nota: regarding the ceap MQ135 sensor, i will post on my blog as soon as possibile my Co2 correlation with the MHZ14 sensor... it seams that the MQ135 works pretty well from 200 to 2000ppm of CO2!
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e.mail: davide...@gmail.com
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Matteo Mortari
Ciao Davide,
thank you for your feedback. Indeed not an easy topic, due to difficulty in finding availability of calibrated instrumentation to make correlation with, I guess.
I explain reason behind my original enquiry, as interestingly, can be found other communities online trying similar correlation experiments between very expensive instruments and more community-driven makings or consumer products. For example aqicn.org blog ref [1].
In Italy PM2.5 and PM10 measurement data seems to be published also on regionalA.R.P.A. websites, if I take for example Lombardia region ref [2] some data is available, but unfortunately appears only daily average, while for other indicators is maximum daily.
I thought worth mentioning ref [2] anyway, maybe if you are also in Italy could lookup your regionalA.R.P.A. website if it's publishing this data for a nearby station, possibly is not very fine grained as wished for, but could be a way for you to try out the formula discussed above?
Maybe not so much in this reply, but potentially a help to get the ball rolling?
Ciao
Refs
[1] http://aqicn.org/faq/2013-09-08/dylos-air-particule-counter-experimentation-part-1/
[2] http://ita.arpalombardia.it/ITA/qaria/listaMI.asp
Simone Cortesi
<matteo....@gmail.com> wrote:
> In Italy PM2.5 and PM10 measurement data seems to be published also on regionalA.R.P.A. websites, if I take for example Lombardia region ref [2] some data is available, but unfortunately appears only daily average, while for other indicators is maximum daily.
working on developing a system that would allow them to supply raw
data for all of the sensors (nearly 2.8M reading/day).
--
-S
Davide Gironi
if anyone need it, i've develop a xively logger, which i've used to log data from a cheap MQ135 sensor, to compare it against mh-z14 looking for the CO2 response of the cheap electro-checmical sensor. it can be easly converted to log other data, i will post the logger code in my blog as soon as possible, and also the MQ135 CO2 mathed results.
Does anyone look at the moving average alghoritm of Michael Taylor here?https://github.com/JSchapiro/AirGo
(we should also use italian i suppose... lol :) )
AQcalc Team at Acculation
You might want to check out AQcalc app for iOS and obtain a Dylos DC1100 (both pro and non-pro are supported by the app). This should give you an inexpensive way to obtain some sort of calibration. The app also lets compare against current EPA readings, which provide a time-averaged PM2.5 and PM10 using traditional (i.e., expensive) technology, so if you are in the US the app will help you calibrate that way as well (and confirm the apps AQE and Dylos-derived readings are in the right ball park.)
Point out our app takes into account humidity and weather conditions, and assumes automobile (or at least combustion) is the source of your pollutants.
Your equation above (I believe) assumes constant density for the particulate matter. This is fine if the pollutant doesn't change, but having lived in a city once nearly engulfed by forest fires (San Diego), I can tell you that the pollutant source does sometimes change for PM2.5! It would good to have data on how particulate masses change when the primary source goes from automobile to something else like forest fire or volcanic ash.
Your regression assumes that the density is constant, which is only true if humidity, weather, and pollutant source are constant. (But it may be a good enough approximation.)
You can obtain more information (and instructions on setting up your calibration) from our blog, here: http://www.acculation.com/blog
Matteo Mortari
Last time I spoke to ARPA Lombardia (in december) they were actively
working on developing a system that would allow them to supply raw
data for all of the sensors (nearly 2.8M reading/day).
Adam Altman
and/or the % breakdowns of pollutant sources for major cities?
Simone Cortesi
> Ciao Simone, thanks for the information and sounds like a great news indeed
> !
> May I kindly ask, are you aware any channel I could "subscribe" to, in order
> be informed on the progress and when it will be ultimately available,
> please?
aperitivo in Milano.
--
-S