EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: Miyuki on April 23, 2024, 10:56:09 am
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Hi folks,
I'm trying to find the best way to detect "smell", not one particular but basically from all burning of coal and wood.
The main purpose is to detect when clean air can be draught into the house.
I do not think particular matter alone will do the trick as there are probably many volatile compounds that are annoying even in small quantities.
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Time ago, one university mobile research vehicle used these to gather road side polution level. https://en.wikipedia.org/wiki/Mass_spectrometry
Photo is typical test lab that do safety certification of consumer goods (laws regulation, insurance, bank requirement) that we use daily.
This measure 5 chemicals plus two particulate. Some road side permanant station can be 2 x 1 x 2 meters or even larger.
https://en.wikipedia.org/wiki/Air_quality_index
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There was an article on Hackaday, about a commercial device that was monitoring air quality + radiation levels, and if allowed, the software was also uploading the data in a global network of air and radiation monitoring.
https://hackaday.com/2015/12/07/globally-distributed-sensor-net-monitors-air-quality-and-radiation/
The author (Radu Motisan https://hackaday.io/radhoo) turned that into a business later, and the device evolved with time, maybe now they detect air smells, too. This one is from 2017: https://hackaday.io/project/8334-city-air-quality
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A particulate detector (PM 2.5 style) ought to be able to sense such combustion products. If you're worried about insufficient fresh air entering the room (which would lead to a greater level of incomplete combustion products and smell) you should probably fit a Carbon Monoxide detector / alarm - I would do that anyway if you have an open fire.
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A VOC (volatile organic compounds) sensor might work.
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Combustion produces CO2 (among other things), so detect that with NDIR. CO2 absorption at 4.26 micron.
https://www.co2meter.com/blogs/news/co2-carbon-dioxide-detector (https://www.co2meter.com/blogs/news/co2-carbon-dioxide-detector)
Don't forget to incorporate a filter that is routinely changed so the emitter and sensor doesn't get covered with creosote, ash or smoke residue.
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Try looking at a Honeywell minimax x4 as a starting point
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I'm trying to find the best way to detect "smell", not one particular but basically from all burning of coal and wood.
The main purpose is to detect when clean air can be draught into the house.
IDK if this helps, but my car has an "air quality sensor" that is used for this exact purpose--if the outside air is not clean, it switches to recirculating the interior air through the carbon filter.
I've no idea how they actually work, but here's an example:
https://www.worldcarparts.co.uk/air-quality-sensor-for-volvo-s80-xc60-xc70-xc70-cross-country (https://www.worldcarparts.co.uk/air-quality-sensor-for-volvo-s80-xc60-xc70-xc70-cross-country)