air pollution particulate sensor package

On Monday, June 30, 2014 3:05:42 PM UTC-4, gyroma...@gmail.com wrote:

Hi,



This message is related to my earlier request for advice in the topic 'finding electronics design and fabrication expertise for a project'.



Because of the kindness of the group members here, I am posting more details about the project and aims.



The overall aim is to develop and deploy inexpensive 'personal' air pollution monitors. For the environment in which I am interested, a major pollutant concern is particulates arising from biomass combustion, coal burning, and car exhaust.



Although these may be inconsistent aims, I am interested in having a device that...

- can measure particulate concentrations (and perhaps temperature and humidity levels)

- is low cost, so that many devices can be deployed within a constrained project budget

- has a good degree of concordance (at least qualitatively) with accurate stationary monitoring stations

- can be read with an app on a cellphone or similar device (bluetooth?)

- is convenient to the wearer of the device, e.g, is robust and has the ability to run on batteries for a few days at a time



I anticipate that a user (or environmental health scientist or health care professional guiding the users) might want to record reading at several points during the day, not continuously.



There are several projects I have found on the web focused on devices to quantify particulates in the air, but I don't think that they satisfy the aims above.



The closest instrument that I could find is detailed in a PhD dissertation by David Holstius, a chapter of which I have posted here:



https://www.dropbox.com/s/azs0dqzgpffppl1/Holstius2014dissertation_Ch3.pdf



Because of my lack of training in the field of electronics, I do not know if the detection method, components, and overall design chosen by this individual would be appropriate as a starting platform to achieve the aims above.



Any input or suggestions would be greatly appreciated.



Thank you again.



-gyro

I encourage you to talk with the docs on the phone at the NIH SBIR National
Heart Lung Institute, as I remember. You said you were not skilled at
electronic design - these docs know even less. The NCI also a possibility.
It's going to take the resources to develop what you want - The docs are quite
encouraging, often.

And, whether or not you know it, you are a legitimate developer of low cost
particulate detection systems. If you talk with the docs on the phone, you
would be primarily asking them questions, such as, "Is this a legitimate
topic to apply for?" and "Do I need to partner with a researcher in this field?"
(probably both yes.)

 

[George Herold]

On Wednesday, July 2, 2014 4:23:04 PM UTC-4, Phil Hobbs wrote:

On 07/02/2014 03:27 PM, haiticare2011@gmail.com wrote:

snip
Phil
What kind of mechanical design facilities are you looking for?
jb

It's more the fabrication that's the issue. Aligning stuff to a few arc
seconds with ball-screw tilt stages is a mug's game.

I'm reluctant to post 'cause you are most likely three thoughts ahead of me.. but anyway,

There are some wickedly fine pitched threads now.

longer lever arm

Double micrometer..(is that the right name?)
(It's got tick marks of 1 micron (or something like that.. I can look it up.))

Use a piezo stack and turn a pot. The quick and dirty way to do this
is just to stick the piezo underneath the tip of the ball-tipped adjustment screw.
AE0203D04F is what we use.
Here?
http://store.bravoelectro.com/ceramicpiezoactuators-ae0203d04fbrpiezoactuatormaxdisplacement46m2x3x5mm-p-1502.html

George H.

Cheers



Phil Hobbs





--

Dr Philip C D Hobbs

Principal Consultant

ElectroOptical Innovations LLC

Optics, Electro-optics, Photonics, Analog Electronics



160 North State Road #203

Briarcliff Manor NY 10510



hobbs at electrooptical dot net

http://electrooptical.net

 

[Phil Hobbs]

On 07/02/2014 11:31 PM, josephkk wrote:

On Tue, 01 Jul 2014 21:41:33 -0400, Phil Hobbs <hobbs@electrooptical.net
wrote:


If anyone feels the laws need to be reworked, then get involved and help
shape some new legislation.

Actually the current legislation is nearly correct. It is set up so that
regulation does the adapting, by leveraging the best repeatable science
available.

I find especially ridiculous the idea that today's brake pads don't stop
the vehicles well enough. lol. I remember the junk being made in the
US in the early 70's. Today's cars are the safest we have ever driven.


Metal brake pads have to warm up to work properly, whereas asbestos ones
didn't. Of course, anyone who ever uses "lol" for anything might not
understand actual data.

Metal in brake pads came in well before asbestos went out. Its
superiority in thermal fading resistance to non-metal brake pads made it a
market winner.

Cheers

Phil Hobbs

Brake fade isn't caused primarily by hot pads, it's caused by boiling
brake fluid. And earlier metal pads also contained asbestos.

Cheers

Phil

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

 

On Wed, 02 Jul 2014 20:19:16 -0700, josephkk
<joseph_barrett@sbcglobal.net> wrote:

On Mon, 30 Jun 2014 18:13:50 -0400, Phil Hobbs <hobbs@electrooptical.net
wrote:

On 6/30/2014 5:22 PM, RobertMacy wrote:
On Mon, 30 Jun 2014 13:43:17 -0700, John Larkin
jlarkin@highlandtechnology.com> wrote:

...snip...

Cars aren't bad. Diesels, in busses, trucks, and construction/farm
machinery, are.

I'm a bit skeptical about the evils of CO2, but particulates are nasty
for people and the planet.

Particulates melt snow, which is especially evil.

Cars aren't bad. What about thousands of brake linings turning to
powedery dust at a Stop sign ??

The dust is pretty large compared with diesel smoke particles, so it
doesn't penetrate very far into your lungs. They got rid of the
asbestos awhile back, which was a pity. Chrysotile asbestos is nasty,
serpentine basically isn't.

Cheers

Phil Hobbs

Be glad if you don't live in an area with naturally occurring asbestos. I
live near lots of them.

Natural asbestos isn't a big problem. It's the results of the
machining of the stuff that makes the nasties. Rocks don't often get
into the lungs.

 

[Jeff Liebermann]

On Mon, 30 Jun 2014 21:13:17 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

I added 2 more photos of the inside of the light box to the web pile:
<http://www.learnbydestroying.com/jeffl/Nikken%201394%20Air%20Quality%20Monitor/Nikken-AQM-08.jpg>
<http://www.learnbydestroying.com/jeffl/Nikken%201394%20Air%20Quality%20Monitor/Nikken-AQM-09.jpg
<http://www.learnbydestroying.com/jeffl/Nikken%201394%20Air%20Quality%20Monitor/>
Looks like it's an optical scattering system.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Steve Wilson]

Jeff Liebermann <jeffl@cruzio.com> wrote:

On Mon, 30 Jun 2014 21:13:17 -0700, Jeff Liebermann <jeffl@cruzio.com
wrote:

I added 2 more photos of the inside of the light box to the web pile:
http://www.learnbydestroying.com/jeffl/Nikken%201394%20Air%20Quality%2
0Monitor/Nikken-AQM-08.jpg
http://www.learnbydestroying.com/jeffl/Nikken%201394%20Air%20Quality%2
0Monitor/Nikken-AQM-09.jpg
http://www.learnbydestroying.com/jeffl/Nikken%201394%20Air%20Quality%2
0Monitor/> Looks like it's an optical scattering system.

Thanks. That is very interesting. In Nikken-AQM-09.jpg, the BA10324A
looks like a slow op amp, similar to the LM358

http://datasheet.octopart.com/BA10324A-Rohm-datasheet-8321777.pdf

I'm surprised the particles really move that slowly through the focal
point that the BA10324A can follow them.

I see the symbol for Q2, but I can't find Q1. Did they miscount, or is it
somewhere on the other side of the board?

D1 and D2 look like dual diodes. Is this some kind of log converter? Your
photos are excellent, but it's kind of hard to trace the circuit looking
at black traces on a black soldermask. I'll wait until mine arrives so I
can trace the circuit.

Maybe an optical illusion, but the board seems very thick looking at the
two screw holes.

I'm glad you were able to get it apart without destroying it. That means
I can try monitoring the signals.

Mine should arrive next week and I'll compare the readings with the
Dylos.

It would be nice if the Nikken can get down to 0.5 micron. It is battery
powered and would be a lot more convenient than lugging the Dylos around
with the power cord. It's a bit awkward trying to find an AC outlet,
especially if it's far from where I want to monitor.

Very interesting. Thanks, Jeff

 

[Jeff Liebermann]

On Fri, 04 Jul 2014 05:14:45 GMT, Steve Wilson <none@nospam.com>
wrote:

That's the issue. How fine is the focal point, and how fast do the
particles move through?

Well, the spot diameter could be measured. The emitter doesn't look
like anything special. Just an ordinary LED operating in near IR
region. You can see near IR with a digital camera (try it on your TV
remote control). A little cancerous cigarette smog, and the light
beam should be visible.

Maybe wise. The IR emitter may be sensitive to ESD. But I'd expect some
vias to connect to the other side.

I'm sure I could have removed it without much difficulty. I just
didn't think it was worth the risk. I'm more worried about trashing
the calibration than breaking anything.

Yes, I thought that was strange. Wouldn't high voltage need a corona
generator upstream? Maybe it's a light baffle.

Please note that it was a guess(tm) as to the purpose of the insulated
plate. I still don't understand its function as the plate is NOT in
the air flow going to the optical dust sensor. I'm fairly sure it's
not a high voltage system because of the nylon insulators and the lack
of any high voltage components on the PCB. More Googling, I guess.

How the IR dust sensor works:
Sharp:
<http://www.digikey.com/articles/techzone/2014/may/sniffing-the-air-sensors-for-monitoring-air-quality-and-safety>
<http://www.digikey.com/us/en/techzone/sensors/supplier/Sharp_Microelectronics__425.html>
<http://www.sharpsma.com/webfm_send/1488>
<https://www.sparkfun.com/products/9689>
<http://www.howmuchsnow.com/arduino/airquality/>

Shinyei:
<http://www.sca-shinyei.com/particlesensor>
<http://www.sca-shinyei.com/pdf/PPD42NS.pdf>
Taking it apart (with schematic):
<http://takingspace.org/wp-content/uploads/ShinyeiPPD42NS_Deconstruction_TracyAllen.pdf>
Outdoor air monitoring in Beijing:
<http://aqicn.org/sensor/shinyei/>
More of the same:
<https://www.google.com/#q=shinyei+PPD42ns>

There were a half dozen or so when I looked. Some went as high as $400.
They are all gone now. Mine was $17.99 plus $16.34 shipping.

That's what happens when people read this newsgroup.
There are still 3 for sale/auction:
http://www.ebay.com/itm/151346164608
http://www.ebay.com/itm/191220658083
http://www.ebay.com/itm/331247326123

The large particles don't do as much damage as the small ones, which
lodge in your lungs. According to the Dylos measurements, the small ones
are about ten times more numerous than the large ones. But I found a
different environment yesterday where the ratio was closer to 16%. That
should be telling me something, but I don't know what yet.
I'm really interested to see some waveforms.

According to my random reading, one can distinguish between various
types of dust sources by the waveform.

As far as I can tell, the
Dylos and Nikken may operate the same way, so I'm expecting similar
results. I'm hoping to be able to tweak the Nikken to get down to 0.3
micron or lower. Maybe add a comparator to exclude the large ones, and a
pot for variable thresholds.

That's down to the size of mold and possibly bacteria.

You can differentiate particle size by pulse width. The Shinyei
detector claims 1 micron minimum on the data sheet. My guess(tm) is
that something in either the amplifiers that follow or the air speed
limit the upper frequency response. The faster the particle goes by,
the narrower the pulse. You might be able to slow down the air flow
in order to "stretch" the pulse width.

Another possible way might be to artificially increase the particle
size by making small particles clump together as in an electrostatic
precipitator. Equal air flow through two different ducts. One duct
would give the dust particles a positive charge, the other negative.
When recombined, they would clump together forming roughly spherical
ummm... clumps, which should produce a much larger pulse width.

Good luck.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

On Thursday, July 3, 2014 12:45:24 PM UTC-4, George Herold wrote:

On Wednesday, July 2, 2014 4:23:04 PM UTC-4, Phil Hobbs wrote:

On 07/02/2014 03:27 PM, haitiwwwcare2011@gmail.com wrote:



snip

Phil

What kind of mechanical design facilities are you looking for?

jb



It's more the fabrication that's the issue. Aligning stuff to a few arc

seconds with ball-screw tilt stages is a mug's game.



I'm reluctant to post 'cause you are most likely three thoughts ahead of me.. but anyway,



There are some wickedly fine pitched threads now.



longer lever arm



Double micrometer..(is that the right name?)

(It's got tick marks of 1 micron (or something like that.. I can look it up.))



Use a piezo stack and turn a pot. The quick and dirty way to do this

is just to stick the piezo underneath the tip of the ball-tipped adjustment screw.

AE0203D04F is what we use.

Here?

http://store.bravoelectro.com/ceramicpiezoactuators-ae0203d04fbrpiezoactuatormaxdisplacement46m2x3x5mm-p-1502.html



George H.









Cheers







Phil Hobbs











--



Dr Philip C D Hobbs



Principal Consultant



ElectroOptical Innovations LLC



Optics, Electro-optics, Photonics, Analog Electronics







160 North State Road #203



Briarcliff Manor NY 10510







hobbs at electrooptical dot net



http://electrooptical.net

interesting info - what is max displacement of th piezo?
voltage?

 

[Steve Wilson]

On Fri, 04 Jul 2014 05:14:45 GMT, Steve Wilson <none@nospam.com
wrote:

That's the issue. How fine is the focal point, and how fast do
the particles move through?

Well, the spot diameter could be measured. The emitter doesn't
look like anything special. Just an ordinary LED operating in near
IR region. You can see near IR with a digital camera (try it on
your TV remote control). A little cancerous cigarette smog, and
the light beam should be visible.

I wonder why they want to use near ir. I would think blue, as in
Blu-Ray, or a uv led would be better for catching the small
particles that do the real damage.

OTOH, it might be possible to use an RGB led and get more
information about the size distribution by changing the color.

Maybe wise. The IR emitter may be sensitive to ESD. But I'd
expect some vias to connect to the other side.

I'm sure I could have removed it without much difficulty. I just
didn't think it was worth the risk. I'm more worried about
trashing the calibration than breaking anything.

I will calibrate the unit against the Dylos. Then I can do whatever
I want and check it against the Dylos to verify the calibration.

How the IR dust sensor works:

Sharp:

http://www.digikey.com/articles/techzone/2014/may/sniffing-the-air-
sensors-for-monitoring-air-quality-and-safety
http://www.digikey.com/us/en/techzone/sensors/supplier/Sharp_Microelec
tronics__425.html
http://www.sharpsma.com/webfm_send/1488
https://www.sparkfun.com/products/9689
http://www.howmuchsnow.com/arduino/airquality/

Shinyei:

http://www.sca-shinyei.com/particlesensor
http://www.sca-shinyei.com/pdf/PPD42NS.pdf> Taking it apart (with
schematic):

http://takingspace.org/wp-
content/uploads/ShinyeiPPD42NS_Deconstruction_TracyAllen.pdf
Outdoor air monitoring in Beijing:

http://aqicn.org/sensor/shinyei/> More of the same:

These are extremely valuable links. Thanks for taking the time to
search and post them.

I'm always amazed at how you can find so many useful links in such a
short time. You should start classes and show us how you do it.

According to my random reading, one can distinguish between
various types of dust sources by the waveform.

It would be very interesting if you had any links. I'd like to find
out what this stuff is and where it comes from.

As far as I can tell, the Dylos and Nikken may operate the same
way, so I'm expecting similar results. I'm hoping to be able to
tweak the Nikken to get down to 0.3 micron or lower. Maybe add a
comparator to exclude the large ones, and a pot for variable
thresholds.

That's down to the size of mold and possibly bacteria.

I found you can go even lower, down to 3 nm and below. Here's one
example using condensation:

"Measuring d<3 nm particles with a Condensation Particle Counter"

ftp://ftp.nilu.no/ACCENT/files/sgro1.pdf

Mold spores, bacteria and viruses are serious health hazards. The
problem is how to distinguish between the pathogens and ordinary
debris.

OTOH, it may be better to concentrate on making a particle filter
that simply strips everything from the room air. Then it doesn't
matter what they are.

But I need a particle counter that goes below the 0.5 um of the
Dylos to verify the performance of the filter. The Nikken looks like
an ideal platform for experimentation. It has a light chamber that
is easy to get to, dual lens for better light handling, battery
power for portable operation, plenty of room for additional
circuits, probably easy to add USB for data transfer, and so on.

I'm really pleased and grateful that you posted the original info on
the burning pcb. It has led to much greater understanding of the
problem, and I will soon have a Nikken in my hands for further work.

You can differentiate particle size by pulse width. The Shinyei
detector claims 1 micron minimum on the data sheet. My guess(tm)
is that something in either the amplifiers that follow or the air
speed limit the upper frequency response. The faster the particle
goes by, the narrower the pulse. You might be able to slow down
the air flow in order to "stretch" the pulse width.

It would be very hard to maintain calibration using pulse width. The
calibration would depend on air velocity, which would depend on the
fan speed, how dirty the blades were, bearing friction, turbulence,
and so on.

As Phil mentioned earlier, pulse amplitude is pretty universal in
the high end counters, and would be much easier to give stable
results.

Another possible way might be to artificially increase the
particle size by making small particles clump together as in an
electrostatic precipitator. Equal air flow through two different
ducts. One duct would give the dust particles a positive charge,
the other negative.

That is how condensation particle counters work. Here's an excerpt:

"In general, laminar-flow CPCs operate by drawing an aerosol sample
continuously through a heated saturator, in which alcohol is
vaporized and diffuses into the sample stream. Together, the aerosol
sample and alcohol vapor pass into a cooled condenser where the
alcohol vapor becomes supersaturated and ready to condense."

"Particles present in the sample stream serve as condensation sites
for the alcohol vapor. Once condensation begins, particles grow
quickly into larger alcohol droplets and pass through an optical
detector where they are counted easily."

http://www.ferret.com.au/ODIN/PDF/Showcases/100428.pdf

When recombined, they would clump together forming roughly
spherical ummm... clumps, which should produce a much larger pulse
width.

And higher amplitude!

> Good luck.

Thanks!

Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Sun, 06 Jul 2014 10:20:02 GMT, Steve Wilson <none@nospam.com>
wrote:

I wonder why they want to use near ir. I would think blue, as in
Blu-Ray, or a uv led would be better for catching the small
particles that do the real damage.

My guess(tm) is because the device is looking only for large particles
(>1 micron) such as cigarette smog and not small particles such as
mold and bacteria. The device has been around for a long time,
possibly before cheap UV emitters and before GaN, InGaN and AlGaN
detectors were commonly available. However, it might also be
something as simple as the age of the Nikken device, which probably
preceded cheap UV components.

I'm always amazed at how you can find so many useful links in such a
short time. You should start classes and show us how you do it.

No need for a class and there are only a few tricks:
1. Use Google images. If you're looking for a schematic of
something, search for schematic images, not for text.
2. Know thy buzzwords. The proper selection of search terms is
paramount. I usually dive into the Wikipedia article first to extract
the necessary buzzwords, and then search for them either individually
or as a group.
3. Don't rely completely on Google search. I like to use Blekko when
I'm stumped, but which does have a learning curve:
<http://blekko.com>
4. If you want research papers and/or patents, use Google Scholar
search:
<http://scholar.google.com>
<https://www.google.com/?tbm=pts>
5. When posting a link, try to reduce it to only the necessary parts,
removing all the tracking info, and irrelevant detail. That's not
easy on some searches and does require learning how the URL's work. I
guess that might be a worthy topic for a web page (but not a class).

The rest is just reading. I must admit that I'm more into speed than
accuracy, which results in my missing some obvious points, but overall
seems to work well.

I also like to read pages backwards, starting at the bottom. Many web
authors have the common affliction of describing problems and
solutions in reverse order. They write like a mystery story, where
the details are supplied first, and the important conclusions at the
end.

I hope this helps.

According to my random reading, one can distinguish between
various types of dust sources by the waveform.

It would be very interesting if you had any links. I'd like to find
out what this stuff is and where it comes from.

I would have posted a link if I had found something relevant. I'll
try again, but not for a few days. Busy with other projects.

You can differentiate particle size by pulse width. The Shinyei
detector claims 1 micron minimum on the data sheet. My guess(tm)
is that something in either the amplifiers that follow or the air
speed limit the upper frequency response. The faster the particle
goes by, the narrower the pulse. You might be able to slow down
the air flow in order to "stretch" the pulse width.

It would be very hard to maintain calibration using pulse width. The
calibration would depend on air velocity, which would depend on the
fan speed, how dirty the blades were, bearing friction, turbulence,
and so on.

I can't do anything to compensate for filth in the ducting, but
measuring air speed is fairly trivial with a hot wire anemometer. I've
built several for weather stations that are quite useful even at low
wind speeds. If fan bearing (more likely bushing) wear is deemed a
problem, then a feedback loop with the hot wire anemometer controlling
the fan speed should compensate for any variations in speed. Of
course, altitude and temperature enter into the equations, so this
isn't really trivial, but methinks can be accomplished.

The problem is that you seem to be designing an "instrument" rather
than something for home use. The requirements for each are quite
different in areas of accuracy, calibration, repeatability, etc. It's
much easier to take a precision instrument, and downgrade it for home
use, than to convert something crude into a precision instrument. For
example, your question about identifying particle composition might be
better addressed with gas chromatography or possibly a mass
spectrometer.


Marginally related anecdote: You don't really need all the technology
to count dust particles. I once had to deal with a serious airborne
pollution problem, twice. I'll leave out the details (unless someone
wants them). The problem was to measure how much dust was being
transported by the HVAC ducting. I didn't have time to rent air
quality instrumentation and just needed something fast. I purchased
some sticky back window shelf paper[1]. I placed some 100 cm squares
in the air stream, and gave it about 30 minutes to collect some dust.
With a microscope, reticule, and my miserable math, I estimated the
particle density from several small sample area. The microscope also
gave me a clue as to what I was counting. I made an order of
magnitude math error, but the dust problem was sufficiently bad that
it didn't matter. In one case, the dust was coming from a nearby
industrial plant with a malfunctional electrostatic precipitator. In
the other, the 1989 earthquake had broken open the HVAC ceiling
ducting joints which allowed the introduction of nearby blown
insulation into the air ducts.

[1] Use paper, not vinyl as the vinyl will build up a static charge
from the air flow.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Steve Wilson]

I just wanted to thank you for all the time and effort you have put in this
thread.

Your information has been very helpful and I will put it to good use.

 

[George Herold]

On Sunday, July 6, 2014 9:00:36 AM UTC-4, haitic...@gmail.com wrote:

On Thursday, July 3, 2014 12:45:24 PM UTC-4, George Herold wrote:

On Wednesday, July 2, 2014 4:23:04 PM UTC-4, Phil Hobbs wrote:


http://store.bravoelectro.com/ceramicpiezoactuators-ae0203d04fbrpiezoactuatormaxdisplacement46m2x3x5mm-p-1502.html


interesting info - what is max displacement of th piezo?
voltage?

I think it's 4 microns at 100V.. but that may be 150V.

George H.

 

I'm always amazed at how you can find so many useful links in such a
short time. You should start classes and show us how you do it.

Here is another "killer" way to get technical info:

Google "Google patents advanced"

The link will put you on Google patents.

Google will even link out from patents to relevant non-patent articles.

It's a law that a patent HAS to tell you not only the invention idea, but how
to build it.


Another: If you are looking for a technology area, go to worldcat.org. You can
then get most any book through Interlibrary Loan in ANY library. This includes
theses and downloadable articles.

 

On Monday, June 30, 2014 3:05:42 PM UTC-4, gyroma...@gmail.com wrote:

Hi,



This message is related to my earlier request for advice in the topic 'finding electronics design and fabrication expertise for a project'.



Because of the kindness of the group members here, I am posting more details about the project and aims.



The overall aim is to develop and deploy inexpensive 'personal' air pollution monitors. For the environment in which I am interested, a major pollutant concern is particulates arising from biomass combustion, coal burning, and car exhaust.



Although these may be inconsistent aims, I am interested in having a device that...

- can measure particulate concentrations (and perhaps temperature and humidity levels)

- is low cost, so that many devices can be deployed within a constrained project budget

- has a good degree of concordance (at least qualitatively) with accurate stationary monitoring stations

- can be read with an app on a cellphone or similar device (bluetooth?)

- is convenient to the wearer of the device, e.g, is robust and has the ability to run on batteries for a few days at a time



I anticipate that a user (or environmental health scientist or health care professional guiding the users) might want to record reading at several points during the day, not continuously.



There are several projects I have found on the web focused on devices to quantify particulates in the air, but I don't think that they satisfy the aims above.



The closest instrument that I could find is detailed in a PhD dissertation by David Holstius, a chapter of which I have posted here:



https://www.dropbox.com/s/azs0dqzgpffppl1/Holstius2014dissertation_Ch3.pdf



Because of my lack of training in the field of electronics, I do not know if the detection method, components, and overall design chosen by this individual would be appropriate as a starting platform to achieve the aims above.



Any input or suggestions would be greatly appreciated.



Thank you again.



-gyro

I grubbed around in funding programs, and EPA just completed a funding round in
March, 14.

They have funded 5 "PM" centers - Particulate Matter. One is at Harvard,
another 2 at UC universities, and I can't remember the other 2.

It would be interesting to ask them what their main limitation and frustration
is, instrument-wise. People love to talk about their problems.

Another way to approach this is NIH - They tend to focus on the biology, but
smart phone medical apps are hot.

jb

 

On Monday, July 7, 2014 11:18:21 AM UTC-4, haitic...@gmail.com wrote:

On Monday, June 30, 2014 3:05:42 PM UTC-4, gyroma...@gmail.com wrote:

Hi,







This message is related to my earlier request for advice in the topic 'finding electronics design and fabrication expertise for a project'.







Because of the kindness of the group members here, I am posting more details about the project and aims.







The overall aim is to develop and deploy inexpensive 'personal' air pollution monitors. For the environment in which I am interested, a major pollutant concern is particulates arising from biomass combustion, coal burning, and car exhaust.







Although these may be inconsistent aims, I am interested in having a device that...



- can measure particulate concentrations (and perhaps temperature and humidity levels)



- is low cost, so that many devices can be deployed within a constrained project budget



- has a good degree of concordance (at least qualitatively) with accurate stationary monitoring stations



- can be read with an app on a cellphone or similar device (bluetooth?)



- is convenient to the wearer of the device, e.g, is robust and has the ability to run on batteries for a few days at a time







I anticipate that a user (or environmental health scientist or health care professional guiding the users) might want to record reading at several points during the day, not continuously.







There are several projects I have found on the web focused on devices to quantify particulates in the air, but I don't think that they satisfy the aims above.







The closest instrument that I could find is detailed in a PhD dissertation by David Holstius, a chapter of which I have posted here:







https://www.dropbox.com/s/azs0dqzgpffppl1/Holstius2014dissertation_Ch3.pdf







Because of my lack of training in the field of electronics, I do not know if the detection method, components, and overall design chosen by this individual would be appropriate as a starting platform to achieve the aims above.







Any input or suggestions would be greatly appreciated.







Thank you again.







-gyro



I grubbed around in funding programs, and EPA just completed a funding round in

March, 14.



They have funded 5 "PM" centers - Particulate Matter. One is at Harvard,

another 2 at UC universities, and I can't remember the other 2.



It would be interesting to ask them what their main limitation and frustration

is, instrument-wise. People love to talk about their problems.



Another way to approach this is NIH - They tend to focus on the biology, but

smart phone medical apps are hot.



jb

I just googled some more "particulate smartphone." There doesn't seem to be a
genuine optical detector that is low cost in existence.

This is kind of thing that NIH funds, of dubious commercial appeal.