Stupid question from me: Why do you need do measurements at all? If you
use kerosene lamps, and I guess they must, isn't it better to give advice
how to use the lamps for minimum soot? If they don't follow the
instruction, particle checking won't help. If you have something that
smokes, you will see the pollutions just by switching on a torchlamp with
polarized lens. So, maybe you don't need to use an electronic tester at
all, but just use your eyes and a cheap light source.?
Other wild idea. If you don't need immediate answer whether there are too
much of carbon particles, you may do some typical student lab thing, e.g.
buy a cheap battery fan for one buck, take a empty PET bottle, cut and
remove both ends so you get a tube. Place the fan at one end and a white
coffee filter on the other. Let the fan suck air from stove, kitchen, lamp
or whatever. After consuming some batteries, check if the white filter is
contaminated. Just a basic idea...I'm sure there are very simple ways...two
pins with potential gap, anode attracts particles...air stream through lab
glass with water....tacky tapes...glass plates that attracts aerosols...
...methods that cost one dollar... Have you asked the students in the
country for which you work
Inge
On 30 August 2013 05:36, Wayne Thayer <[log in to unmask]> wrote:
> We still have an order of magnitude of cost problems here: $12 sensor vs.
> $300 decent meter. Of course, more than a sensor is required, but really
> not much. I have it hooked to an Arduino with an added on SD card
> datalogger module. Even in single piece quantity <$60, and for this sensor
> app I might not need the datalogger, saving $20.
>
> This discussion has been great at getting me out of my mental block.
>
> Besides other ideas, I just concluded I should try waving a single thin
> hair in the sensor. If I wave it around a lot and average the result,
> maybe I can get something repeatable. Actual implementation might be a
> thin tungsten rod driven eccentrically by a cheap phone vibrator motor.
>
> I don't believe there is enough profit in this to attract a commercial
> developer. If people don't donate the time to develop it, I think it's a
> no-go.
>
> Wayne
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Inge Hernefjord
> Sent: Friday, August 30, 2013 2:00 AM
> To: [log in to unmask]
> Subject: Re: [TN] Blowing Smoke
>
> Quite different solution: ask HANNA if they can't make a cheap turbdity
> meter. They should, if you tell them the lots of meters needed .
>
>
> http://www.amazon.com/Hanna-Instruments-Turbidity-Technology-Compliant/dp/B002NX0WJG
>
>
> On 29 August 2013 15:59, Pat Goodyear <[log in to unmask]> wrote:
>
> > Optical detector rings a bell, 20 years ago we had a Forward Scatter
> > Meter, we used it at the plant to measure the density of the fog. Had
> > nothing to do with humidity but it was for visibility. If I remember
> > correctly it had a shielded IR light source on one arm facing a
> > shielded photo detector array on an opposite arm about 2 meters
> separating them. I
> > think they use a similar device at airports. Maybe a device of that
> type
> > may work on a smaller scale. Zero point would be no interference, high
> > level would be the point at which the air quality is uninhabitable,
> > and possibly a logarithmic scale in between.
> >
> > Pat
> >
> >
> > On Thu, Aug 29, 2013 at 11:04 AM, Wayne Thayer wrote:
> >
> > That's different thinking!
> >>
> >>
> >> -----Original Message-----
> >> From: TechNet [mailto:[log in to unmask]] On Behalf Of Rivera, Raye
> >> Sent: Thursday, August 29, 2013 1:59 PM
> >> To: [log in to unmask]
> >> Subject: Re: [TN] Blowing Smoke
> >>
> >> If this is an optical detector, why do you need actual smoke? Put a
> >> piece of tinted plexiglass in the detector as a calibration standard
> >> in the field. You can figure out what density of particles it is
> >> equivalent to in a lab with a particle counter.
> >>
> >> Best regards,
> >> Raye Rivera
> >> QA Manager * Canoga Perkins * 818-678-3872 *
> >> [log in to unmask] Message-----
> >> From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Thayer
> >> Sent: Thursday, August 29, 2013 10:35 AM
> >> To: [log in to unmask]
> >> Subject: Re: [TN] Blowing Smoke
> >>
> >> I think what I'm going to try next is two wirewound resistors glued
> >> together with some ceramic paste, or maybe just build a hammock
> >> between them with some aluminum foil. Then try a drop or two of the
> >> liquid they use on model trains to simulate smoke. If that doesn't
> >> get me anywhere, then maybe the heating element from an e-cigarette.
> >>
> >> -----Original Message-----
> >> From: TechNet [mailto:[log in to unmask]] On Behalf Of Steven Creswick
> >> Sent: Thursday, August 29, 2013 1:17 PM
> >> To: [log in to unmask]
> >> Subject: Re: [TN] Blowing Smoke
> >>
> >> Wayne - agree. That's why I pointed you to Gentex. It's optical.
> >> Used to be that all commercial aircraft had these detectors from
> >> Gentex
> >>
> >> Steve C
> >>
> >> -----Original Message-----
> >> From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Thayer
> >> Sent: Thursday, August 29, 2013 1:03 PM
> >> To: [log in to unmask]
> >> Subject: Re: [TN] Blowing Smoke
> >>
> >> In an ionization-based detection system (technically illegal in my
> >> application because of the radioactive source required), you can
> >> check sensitivity by looking at the leakage current through the
> >> ionization chamber. Most of these "in circuit test" systems simply
> >> put a resistor across the ionization chamber and measure the time it
> >> takes set off the alarm.
> >> -----Original Message-----
> >> From: TechNet [mailto:[log in to unmask]] On Behalf Of Steven Creswick
> >> Sent: Thursday, August 29, 2013 12:51 PM
> >> To: [log in to unmask]
> >> Subject: Re: [TN] Blowing Smoke
> >>
> >> Wayne,
> >>
> >> That is a good point about the smoke detectors, since there are two
> >> types
> >> - the ionization types and the particulate types that work by
> >> scattering of light.
> >> Look at FAQ #3 at this site -
> >> http://www.gentex.com/fire-**protection/technical-support<http://www.
> >> gentex.com/fire-protection/technical-support>
> >> It would appear that they have the calibration and degradation issues
> >> worked out. I may still know some people there, but not sure how
> >> much help that would be in this situation.
> >>
> >> We used to ignite a ribbon of Mg to coat the inside of an integrating
> >> sphere with white powder. If you can combust tiny performs of Mg, or
> >> nanofoil as someone else suggested, that seems like it might satisfy
> >> your combustion quantity issue - although may create another issue
> >> with transport and handling....
> >>
> >> Steve C
> >>
> >> -----Original Message-----
> >> From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Thayer
> >> Sent: Thursday, August 29, 2013 12:33 PM
> >> To: [log in to unmask]
> >> Subject: Re: [TN] Blowing Smoke
> >>
> >> Hi Dennis-
> >>
> >> Yes, as you and Richard have pointed out, calibrating particle
> >> sensors is not un-mapped territory. The systems are accurate and
> >> worthy of withstanding the rigors of lawsuits.
> >>
> >> But we can all see that there is a huge gulf between that kind of
> >> calibration and the other end of the spectrum, such as seeing whether
> >> a smoke detector is working OK.
> >>
> >> Another point in that gulf is a counter designed to control a HEPA in
> >> a room where a person has allergies. For that, they don't use a
> >> laser for illuminating the particles, they just use an IR LED. Hence
> >> they don't know if they are looking at one giant particle or a bunch
> >> of tiny ones. But they actually appear to be useful anyway, and the
> >> cost for the sensor from DigiKey is $12. Sharp tells you right up
> >> front on the data sheet that the LED will fade over time, by as much
> >> as 50%, with a corresponding drop in sensitivity. Also, the
> >> calibration curves provided in the data sheet show a very wide range of
> "typical" calibration slopes.
> >>
> >> So my gut tells me there should be some way of making a repeatable
> >> experiment that could be used for comparing these cheap sensors to
> >> each other and to watch the degradation in performance vs. time. I
> >> need to vaporize a defined amount of material in a closed volume.
> >> Turns out to be more challenging than I thought! It seems the
> >> diffusion of the vaporized material is actually the easy part.
> >> Complete combustion of a defined amount of material is hard.
> >>
> >> Wayne
> >>
> >> From: Dennis Fritz [mailto:[log in to unmask]]
> >> Sent: Thursday, August 29, 2013 11:27 AM
> >> To: Wayne Thayer
> >> Subject: Re: [TN] Blowing Smoke
> >>
> >> Good luck on this one, especially the "The idea is a cheap sensor" part.
> >>
> >> Particle measurment in either air or liquid is pretty well developed.
> >> IEST is the standards organization and there are also IEC
> >> international regulations/certifications
> >>
> >> I googled "air particle counter calibration" and a lot of stuff came
> >> up - most all probably too complicated for what you need - "cheap".
> >> However, this link gives some background on your problem and a bit of
> >> "who certifies what".
> >>
> >>
> >> http://www.particle.com/wp-**content/uploads/downloads/**
> >> 2012/02/WP-MET-ONE-ISO-<http://www.particle.com/wp-content/uploads/do
> >> wnloads/2012/02/WP-MET-ONE-ISO->
> >> 21501-Calibration-of-APC-from-**Metrology-Perspective-US.pdf
> >>
> >> Good luck.
> >>
> >> -----Original Message-----
> >> From: Wayne Thayer
> >> <[log in to unmask]<mailto:w**[log in to unmask]<[log in to unmask]
> >> COM>
> >> >>
> >> To: TechNet <[log in to unmask]<mailto:TechNe**[log in to unmask]
> >> <[log in to unmask]>>>
> >> Sent: Thu, Aug 29, 2013 10:06 am
> >> Subject: Re: [TN] Blowing Smoke
> >>
> >> To answer previous question:
> >>
> >>
> >>
> >> The idea is a cheap sensor. 3rd world homes are notoriously smoky
> >> due to the
> >>
> >> cooking fire and due to kerosene lamps. Most of the smoke is carbon.
> >> There are
> >>
> >> lots of ideas for improving these homes (like LED lights with solar
> >> rechargers)
> >>
> >> so we can "improve their lot" by making it more healthy for kids to
> >> study inside
> >>
> >> (or maybe so they can buy stuff on the internet?). Anyway, the aid
> >> groups want
> >>
> >> a way to see what the bang for buck is in improving the indoor
> >> environment, so
> >>
> >> they need a sensor. These sensors work by shining an LED or laser
> >> through an
> >>
> >> air stream, and measuring the amount of light which is reflected
> >> off-axis by the
> >>
> >> particulates in the air.
> >>
> >>
> >>
> >> How does the bicycle pump (actually I'm imagining a disposable
> >> plastic
> >> syringe)
> >>
> >> pick up a defined amount of cigarette smoke? Maybe arrange a fixture
> >> which
> >>
> >> leaves the cigarette burning and allows the smoke to just rise into
> >> the open end
> >>
> >> of the syringe for a set amount of time, then put the plunger in.
> >> Might
> >>
> >> work-cheap to try!
> >>
> >>
> >>
> >> As to the other suggestions, such as the nichrome wire, I keep coming
> >> back to
> >>
> >> needing some kind of heated basket so I can make sure I burn 100% of
> >> whatever I
> >>
> >> put in there. A circulating fan and Brownian motion should make the
> >> environment
> >>
> >> pretty uniform, although with the tests I've been doing, I get a
> >> spike with an
> >>
> >> exponential decay as the particles settle. Still, the interior of
> >> the 5 gallon
> >>
> >> bucket appears pretty uniform, even though the peak duration is only
> >> about
> >> 40
> >>
> >> secs.
> >>
> >>
> >>
> >> Wayne
> >>
> >>
> >>
> >> From: Inge Hernefjord
> >> [mailto:[log in to unmask]**<mailto:[log in to unmask]**?>]
> >>
> >> Sent: Thursday, August 29, 2013 4:45 AM
> >>
> >> To: TechNet E-Mail Forum; Wayne Thayer
> >>
> >> Subject: Re: [TN] Blowing Smoke
> >>
> >>
> >>
> >> Don't laugh now, I am serious. A kind of cycle pump, but with a very
> >> small
> >>
> >> diameter nozzle. Pull the handle and suck a second sniff of cigarett
> >> smoke,
> >>
> >> continue pulling handle until pump is filled with air/smoke mixture.
> >> Now press
> >>
> >> handle slowly and you get a constant stream of mixture. Simple and
> cheap.
> >> Guess
> >>
> >> the nozzle should be fractions of a millimeter.
> >>
> >>
> >>
> >> Inge
> >>
> >>
> >>
> >> On 28 August 2013 08:07, Wayne Thayer
> >>
> >> <[log in to unmask]<mailto:w**[log in to unmask]<[log in to unmask]
> >> com>
> >> ><mailto:wt**[log in to unmask] <[log in to unmask]>
> >> om<mailto:[log in to unmask]**?>>>
> >>
> >> wrote:
> >>
> >> OK, here's another problem I've been playing with (although it has
> >> little to do
> >>
> >> with IPC mission, it might be related).
> >>
> >>
> >>
> >> I am trying to build a system for measuring airborne particulates for
> >>
> >> humanitarian organizations looking for inexpensive ways to
> >> measure/monitor
> >>
> >> indoor air quality. There are cheap sensors available which might do
> >> the job,
> >>
> >> but they would need periodic re-calibration.
> >>
> >>
> >>
> >> So I need a controlled, extremely small amount of smoke. At first, I
> >> thought
> >>
> >> this would be trivial: Find a cheap part at DigiKey and put too many
> >> watts
> >>
> >> through it. Way too much smoke and too little control. Then I tried
> >> burning
> >>
> >> thin wires. Too irregular because sometimes they incinerate
> >> completely and
> >>
> >> other times they find a tiny defect and just burn that until the wire
> >> stops
> >>
> >> conducting. Then I tried just heating the wire enough to burn off
> >> the
> >>
> >> insulation. Still too irregular! I did just a few experiments and
> >> got 30%
> >>
> >> variation.
> >>
> >>
> >>
> >> Now I'm starting to think maybe a tiny piece of paper on an
> >> automotive cigarette
> >>
> >> lighter. That's a lot of power to get that glowing, and it is not
> >> convenient to
> >>
> >> attach to. Any other ideas?
> >>
> >>
> >>
> >> Wayne
> >>
> >>
> >>
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