I was peripherally involved in cheap solar panels for 3rd world for a short
time. They are instrumental in changing people's lives in all sorts of ways.
And have seen the benefits of off grid electricity firsthand. EG You can
charge your mobile without taking some days walking into town and back.
(mobiles are a key transformer in those parts of the world)
Smoke inhalation is a big health problem so a way of measuring it would be
good.
Inge's idea is a good starter, perhaps with a chamber of known size, then
you could measure the dispersion easily by lasering across it to an external
sensor(s) off axis. Alternatively reversing it: A syringe could pump into a
chamber lifting and dispersing a known amount of particulates or
introducing same. Would not need power.
The technology for this would be very similar to rain sensing wind screen
wipers.
Regards
Mike Fenner
Bonding Services & Products
M: +44 [0] 7810 526 317
T: +44 [0] 1865 522 663
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Thayer
Sent: Thursday, August 29, 2013 3:07 PM
To: [log in to unmask]
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]]
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:[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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