Hi
I wonder is anybody interested in kicking around a Particulate Monitor design in detail?
Seems like there are some knowledgeable users interested in a open design particulate monitor.
The design looks to me like it requires a combination of talents from the final air quality metric, to electronic to mechanical issues.
From Tim Dye of Sonoma Technology Table
Pollutant |
Health Concern1 |
Atmospheric Concentration Range2 |
Health Standard3 |
Accuracy7 |
Time Resolution |
Location |
|
|||||
Urban |
Rural |
Near Trans. |
Worldwide |
Outdoor |
Indoor |
Season |
||||||
Particles |
||||||||||||
PM2.5 |
R, H, V |
~0-300 mg/m3 |
35 mg/m3 24-hr |
1-5 mg/m3 |
1 min to 1-hr |
ü |
ü |
ü |
ü |
ü |
ü |
Year-round |
PM10 |
R, H, V |
~0-500 mg/m3 |
150 mg/m3 24-hr |
~10 mg/m3 |
1 min to 1-hr |
ü |
ü |
ü |
|
ü |
|
Year-round |
Black Carbon |
H, V |
~0-50 mg/m3 |
None6 |
1-5 mg/m3 |
1 min to 1-hr |
ü |
|
ü |
ü |
ü |
ü |
Year-round |
|
Any comments/ideas/brain waves
If I'm completely on the wrong track, appreciate the feedback/insights.
OK ... now to the bullet points you mention ... my thoughts are:
OK, this is already too long so I'll leave it to here but I'd like to stress that it would be really good to have a dust sensor design that fits the low-cost end and enable more community engagement.
/El Gus
Chris, this is fantastic. �I have to tell you that from all of the conversations I've had with people all over the place up until about a week ago I was convinced that PM was out of the range of possibility for "us". The fact is that if we'd known this when we started this project, we'd have included the Sharp sensor in the standard kit from the beginning. �We just didn't know.
Between yourself and Gus, I think you have really opened the door for accessing what I've understood to be the most important "air quality" metric. �It's really a huge step, and I think a huge part of a project like Air Quality Egg is to be able to provide a platform for people like yourselves to disseminate the work you've done.
HUGE. �Beers are on me fellas.
�
Urban
Rural
Near Trans.
Worldwide
Outdoor
Indoor
Season
Particles
PM2.5
R, H, V
~0-300 mg/m3
35 mg/m3 24-hr
1-5 mg/m3
1 min to 1-hr
�
�
�
�
�
�
Year-round
PM10
R, H, V
~0-500 mg/m3
150 mg/m3�24-hr
~10 mg/m3
1 min to 1-hr
�
�
�
�
�
�
Year-round
Black Carbon
H, V
~0-50 mg/m3
None6
1-5 mg/m3
1 min to 1-hr
�
�
�
�
�
�
Year-round
�
There is also a PM1.0 (a fourth range)�
Looking at the Sharp GP2Y1010AU0F Dust Sensor.
It specifies a minimum Sensitivy of 0.35 V/(0.1mg/m3) and an output voltage range of 3.4V The measuring algorithm is to pulse 100 times a second for 320uSeconds and sample output 280uS after turning on Led.
The GP2Y1010AU0F units seem a bit strange as clearly it doesn�t have a m3 inside its package.
ON its Internal Schematic is says �Dust through hole�.
So as a digital snapshot it can provide a response to any particles that are there � but the IR reflection is likely to be dependent on many factors and might only be found by experimenting.
And then a m3 of air has to be moved past the hole.
However no specification for the depth of the field that dust can be detected � is it 1mm or 10mm (guess at 4mm see later)�
For the electronics the real challenge is the lower end of PM2.5 scale 35 mg/m3 24-hr with an accuracy 1-5 mg/m3
So this 24 hour measurement needs to be distributed over the total number of samples to be taken.
The key it would seems is the accuracy of 1-5 mg/m3
What would GP2Y1010AU0F output look like if it was detecting a particle of 1-5 mg
Well its specified for 350mV/(0.1mg/m3) so maybe this can be 3.5mV/1.0 mg/m3
Which at least on paper looks doable
If a 12bit ADC is used with a 4V range � then it can sample at 1mV. So that looks doable.
Now moving a m3 in say useable time, say 1hr over the front of the hole is a mechanical challenge and possibly some more math.
The hole is 8mm in diameter � but probably not all useable. If it is approximated to 4x4mm with a depth of 4mm � then this is a volume of 64 mm3
So at a sample rate of a 360,000/hr this is �0.023 m3 which is a significantly less than the target of 1 m3 (any holes in my maths).
So this might require some rationalizing on getting to the air flow of 1 m3 / hour.
So the next challenge would be how to differentiate between the three types of particulates � BlackCarbon, PM10 PM2.5
Presumably BlackCarbon is the larger particle � so the process may be about trying to filter out the three particle sizes and do it with a mass of air flowing over it, and then make three separate measurements.
Any ideas?
The other design areas that are a challenge are the
* Moving air over the sensor � can probably be done with a low cost fan, but needs careful design to avoid particulate being blown into the sensor (see data sheet). Seems doable in a detail design.
* Environmental considerations � should survive temperature extremes outdoors from Lima to Patagonia, Jakarta to Bejing, Arizona/Florida to the Canadian North. * Should survive humidity fluctuations. ? Humidity not specified on data sheet. This is a red flag. May not work in humidity, or the very least design should be so condensing moisture drains away. �When inside of the sensor is moisturized, this product does not keep its proper function. Please design the application so that moisturization of the sensor does not happen.��
Any comments/ideas/brain waves
If I'm completely on the wrong track,�appreciate�the feedback/insights.
----- Original Message -----From: Joseph SaavedraSent: Wednesday, April 18, 2012 6:51 PMSubject: Re: PM - Particulate sensor
Great stuff! If useful, I could get info on a pump model we used in my PhD work to sample CO2. The air flows were on the order of 1 liter per minute I think, and the general type of pump is a fish tank pump. Send me an email separately if this would be useful. Philip Orton On Apr 17, 2:09�pm, NeilH <neil...@wllw.net> wrote:Hi I wonder is anybody interested in kicking around a Particulate Monitor design in detail? Seems like there are some knowledgeable users interested in a open design particulate monitor. The design looks to me like it requires a combination of talents from the final air quality metric, to electronic to mechanical issues. From Tim Dye of Sonoma Technology Table *Pollutant* *Health Concern1* *Atmospheric* *Concentration Range2* *Health Standard3* *Accuracy7* *Time Resolution* *Location* * * Urban Rural Near Trans. Worldwide Outdoor Indoor *Season* *Particles* PM2.5 R, H, V ~0-300 mg/m3 35 mg/m3 24-hr 1-5 mg/m3 1 min to 1-hr � � � � � � Year-round PM10 R, H, V ~0-500 mg/m3 150 mg/m3 24-hr ~10 mg/m3 1 min to 1-hr � � � � Year-round Black Carbon H, V ~0-50 mg/m3 None6 1-5 mg/m3 1 min to 1-hr � � � � � Year-round * * There is also a PM1.0 (a fourth range) Looking at the Sharp GP2Y1010AU0F Dust Sensor. It specifies a minimum Sensitivy of 0.35 V/(0.1mg/m3) and an output voltage range of 3.4V The measuring algorithm is to pulse 100 times a second for 320uSeconds and sample output 280uS after turning on Led. The GP2Y1010AU0F units seem a bit strange as clearly it doesn�t have a m3 inside its package. ON its Internal Schematic is says �Dust through hole�. So as a digital snapshot it can provide a response to any particles that are there � but the IR reflection is likely to be dependent on many factors and might only be found by experimenting. And then a m3 of air has to be moved past the hole. However no specification for the depth of the field that dust can be detected � is it 1mm or 10mm (guess at 4mm see later) For the electronics the real challenge is the lower end of PM2.5 scale 35 mg/m3 24-hr with an accuracy 1-5 mg/m3 So this 24 hour measurement needs to be distributed over the total number of samples to be taken. The key it would seems is the accuracy of 1-5 mg/m3 What would GP2Y1010AU0F output look like if it was detecting a particle of 1-5 mg Well its specified for 350mV/(0.1mg/m3) so maybe this can be 3.5mV/1.0 mg/m3 Which at least on paper looks doable If a 12bit ADC is used with a 4V range � then it can sample at 1mV. So that looks doable. Now moving a m3 in say useable time, say 1hr over the front of the hole is a mechanical challenge and possibly some more math. The hole is 8mm in diameter � but probably not all useable. If it is approximated to 4x4mm with a depth of 4mm � then this is a volume of 64 mm3 So at a sample rate of a 360,000/hr this is �0.023 m3 which is a significantly less than the target of 1 m3 (any holes in my maths). So this might require some rationalizing on getting to the air flow of 1 m3 / hour. So the next challenge would be how to differentiate between the three types of particulates � BlackCarbon, PM10 PM2.5 Presumably BlackCarbon is the larger particle � so the process may be about trying to filter out the three particle sizes and do it with a mass of air flowing over it, and then make three separate measurements. Any ideas? The other design areas that are a challenge are the * Moving air over the sensor � can probably be done with a low cost fan, but needs careful design to avoid particulate being blown into the sensor (see data sheet). Seems doable in a detail design. * Environmental considerations � should survive temperature extremes outdoors from Lima to Patagonia, Jakarta to Bejing, Arizona/Florida to the Canadian North. * Should survive humidity fluctuations. ? Humidity not specified on data sheet. This is a red flag. May not work in humidity, or the very least design should be so condensing moisture drains away. �When inside of the sensor is moisturized, this product does not keep its proper function. Please design the application so that moisturization of the sensor does not happen.� Any comments/ideas/brain waves If I'm completely on the wrong track, appreciate the feedback/insights.
2012-04-18T22:29:57.301603Z, 339 2012-04-18T22:39:56.117367Z, 171 2012-04-18T22:44:51.657774Z, 229 2012-04-18T22:49:54.203825Z, 1082 2012-04-18T22:54:59.859396Z, 1519 2012-04-18T22:59:55.334612Z, 1525 2012-04-18T23:04:50.884449Z, 1435 2012-04-18T23:09:56.354095Z, 469 2012-04-18T23:14:51.871184Z, 1112 2012-04-18T23:19:57.468833Z, 924
----- Original Message -----From: NeilHSent: Friday, April 20, 2012 2:54 PMSubject: Re: PM - Particulate sensor
Neil--
Cesar García - @elsatch
Ando con encolamiento para responder correos y los proceso lunes, miércoles y viernes. Si es algo urgente/rápido contáctame por Twitter. Gracias!
Hi All
I’m at a Water Quality Monitoring Conference in Oregon – and there is a lot of discussion on Sensors and using RealTime communications for monitoring.
Yesterday we heard from the National Ecological Observatory Network www.NeonInc.org … setting up a continental scale ecological internet for scientists. A big issue was quality control for the automated data collection. They went through a whole lot of the process from calibration of sensors, to multipile stages for quality control on the data collected, and then finally stress testing sensors for a range of real world conditions.
Then there was the Alliance for Coast Technologies - http://www.act-us.info/evaluations.php - and they were going through how they provide a forum for emerging sensor technologies (validating the measuring technologies) and comparing the results.
One session was a quick introduction to optical sensors using different wavelengths of lights, what substances absorb light – how to calibrate your sensor and check it periodically.
Newfoundland Canada introduced their river monitoring network – how to calibrate the sensors, how they set up a network to respond to threshold exceedance events and having the mining companies take water samples on exceedance events – and ultimately how to manage the false positives that occurred pretty regularly.
Noboby talking about self calibrating networks of sensors – and this is the group that could really benefit from it, and has a lot of brain power – maybe there is an opening for a computer scientist to present on the subject.
Any one of you help me to get a pollen monitoring sensor and also what are all the sensors used for air quality monitoring