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 >> >> >> >> ______________________________**______________________________** >> __________ >> >> This email has been scanned by the Symantec Email Security.cloud service. >> >> For more information please contact helpdesk at x2960 or >> [log in to unmask] <mailto:helpde**[log in to unmask] >> <[log in to unmask]>><mailto:helpdesk@**ipc.org<[log in to unmask]> >> <mailto:hel >> [log in to unmask]>> >> >> ______________________________**______________________________** >> __________ >> >> >> >> >> >> ______________________________**______________________________** >> __________ >> >> This email has been scanned by the Symantec Email Security.cloud service. >> >> For more information please contact helpdesk at x2960 or >> [log in to unmask] <mailto:helpde**[log in to unmask] <[log in to unmask]>> >> >> ______________________________**______________________________** >> __________ >> >> ______________________________**______________________________** >> __________ >> This email has been scanned by the Symantec Email Security.cloud service. >> For more information please contact helpdesk at x2960 or >> [log in to unmask] >> **______________________________**__________ >> >> >> ______________________________**______________________________** >> __________ >> This email has been scanned by the Symantec Email Security.cloud service. >> For more information please contact helpdesk at x2960 or >> [log in to unmask] >> **______________________________**__________ >> >> ______________________________**______________________________** >> __________ >> This email has been scanned by the Symantec Email Security.cloud service. >> For more information please contact helpdesk at x2960 or >> [log in to unmask] >> **______________________________**__________ >> >> >> ______________________________**______________________________** >> __________ >> This email has been scanned by the Symantec Email Security.cloud service. >> For more information please contact helpdesk at x2960 or >> [log in to unmask] >> **______________________________**__________ >> >> ______________________________**______________________________** >> __________ >> This email has been scanned by the Symantec Email Security.cloud service. >> For more information please contact helpdesk at x2960 or >> [log in to unmask] >> **______________________________**__________ >> >> >> ______________________________**______________________________** >> __________ >> This email has been scanned by the Symantec Email Security.cloud service. >> For more information please contact helpdesk at x2960 or >> [log in to unmask] >> **______________________________**__________ >> >> ______________________________**______________________________** >> __________ >> This email has been scanned by the Symantec Email Security.cloud service. >> For more information please contact helpdesk at x2960 or >> [log in to unmask] >> **______________________________**__________ >> > > ______________________________**______________________________**______ > ____ This email has been scanned by the Symantec Email Security.cloud > service. > For more information please contact helpdesk at x2960 or > [log in to unmask] > **______________________________**__________ > ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. 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