Hi Phil-

No problem with organics.

This is a good direction to consider:  An electronic cigarette.  They contain the micro-heater to vaporize the propylene glycol.  I can probably make that controlled by the Arduino I'm using, and pulse width modulate it to adjust how much comes out.  I may need an additional blower of some kind in the system, but that sounds pretty easy.

I'll let you know what I find out.

Thanks,

Wayne


-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]] 
Sent: Wednesday, August 28, 2013 11:25 AM
To: TechNet E-Mail Forum; Wayne Thayer
Subject: RE: [TN] Blowing Smoke

Heat up propylene glycol, oh wait, you need inorganic particulates, right?

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Thayer
Sent: Wednesday, August 28, 2013 8:07 AM
To: [log in to unmask]
Subject: [TN] Blowing Smoke

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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