Any experience with CO or Explosive Vapor sensors?
Mike Green
Posts: 23,101
Anyone have experience with carbon monoxide sensors or gasoline/hydrogen vapor sensors like those used in boating? I'm interested in what kind of interfacing (and sensor models) would be needed for a demonstration type project. This would be part of an interactive art installation and there would be some sort of adjustable threshold used to light different color LEDs. I tried doing a web search, but couldn't even find online datasheets.
Another part of this piece would involve detecting someone's pulse using an IR emitter/phototransistor pair. I know you'd get a periodic variation in IR absorption, maybe do a Fourier transform to look for peaks in the expected range over a 30-60 second data window. Any suggestions / references?
Another part of this piece would involve detecting someone's pulse using an IR emitter/phototransistor pair. I know you'd get a periodic variation in IR absorption, maybe do a Fourier transform to look for peaks in the expected range over a 30-60 second data window. Any suggestions / references?
Comments
http://www.futurlec.com/Gas_Sensors.shtml
I also made a pulse oxcymeter that worked using a parallax light to frequency converter and IR sensors. Search the web for home built pulse oxcymeter (perhaps spell it better) It is made using a piece of 1" pvc water tubing.
Oh wait a sec, i found the pdf on my computer for that attached,
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Think Inside the box first and if that doesn't work..
Re-arrange what's inside the box then...
Think outside the BOX!
Thanks. I've now got a couple of sites for the plain sensors. In many ways, appearance is more important than functionality. An alcohol sensor and a carbon monoxide sensor might be the best since they can be triggered by waving an alcohol wipe nearby or having a cigarette smoker blow smoke on it.
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Think Inside the box first and if that doesn't work..
Re-arrange what's inside the box then...
Think outside the BOX!
www.figarosensor.com/gaslist.html
and
www.synkera.com/products/sensors.htm
The following are electrochemical cells for Carbon Monoxide detection, as found in home safety CO detectors. These use much less operating power (no heater!). The circuit required is a potentiostat, to measure an electrode voltage at practically zero current--usually evaluation modules are available to provide this function. I've looked briefly into hacking into commercial CO alarms, but they are not exactly easy to reverse engineer.
www.citytech.com
and
www.monox.com/about.htm
Either of those technologies have limited lifetime, and please take all their claims of long term stability with a grain of salt. For quantitative measurements, they require frequent recalibration.
At the high end of the price and performance curves are the optoelectronic sensors that use a couple of light wavelengths, one on a peak another in a trough of the target gas light absorption. The price and physical bulk of those are going down, but still relatively big and costly.
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Tracy Allen
www.emesystems.com
Post Edited (Tracy Allen) : 10/27/2007 10:19:04 PM GMT
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Think Inside the box first and if that doesn't work..
Re-arrange what's inside the box then...
Think outside the BOX!
www.parallax.com/dl/docs/prod/prop/Parallel_Computing_Voltammetry.pdf
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Tracy Allen
www.emesystems.com