So, we've got litmus paper, that changes color based on pH. However, there's other types of indicators, that change color based on gas present in the air. For example, lead acetate paper strips indicate H2S presence in the air.
So, imagine a piece of multi-stripped paper, that changes color based on the presence of a variety of compounds in the air, that change the pattern, like a bar- code or a QR code, based on the presence of a diversity of compounds in the air.
These papers would be a way to visualize the smell-codes, but the smell- codes themselves would be just that abstract concept, that information can be encoded and transmitted in smells, and a dog may not even need to have such paper to read messages coded in smellcode.
These codes may have many applications, including scientific communication of smells. Also, a specific smell-encoding could be defined, to write and read such-coded messages, that may be universally usable, say, even after the message encryption.-- Mindey, Apr 12 2020 Sensetivity is a huge problem. You need a pump system to actively draw air through/onto the paper. Chemical weapon detection systems have struggled with this for years, and mostly rely on wet chemistry or semiconductor sensors.
The reaction rate of dry chemistry is fairly slow, and the range of reactions that will actually work "dry" is small; normally, ionization of the reactants in a polar solvent is needed.
It's an interesting idea, tho.
Even human nasal sensetivity is way better than most dry chemistry systems.-- 8th of 7, Apr 12 2020 // Even human nasal sensetivity is way better than most dry chemistry systems.
That's right, we're lagging behind nature in this regard...
// Chemical weapon detection systems have struggled with this for years, and mostly rely on wet chemistry or semiconductor sensors.
Given reactive chemicals needed, such smell-detecting paper could perhaps be best printed with an ink-jet printer in real time, and a camera be observing the color or spectroscopy changes as a result of influx of air...-- Mindey, Apr 12 2020 // lagging behind nature //
Not really, because animal noses are wet chemistry. Compounds contact mucous membranes where they interact with receptors in aqueous solution.
It's incorrect to say that dry chemistry "lags", because the physical chemistry is irreconcilably different. It can simply never perform to the same level.
Iron in water corrodes, either aerobically or anaerobically. Iron in dry air does't corrode (oxidise) to any significant extent because a monomolecular passivated oxide layer rapidly forms, after which there's no path for more oxygen to access the bulk material and the process stops.
The inkjet idea certainly merits further investigation.-- 8th of 7, Apr 12 2020 //we've got litmus paper//
The petals of the forget-me-not behave in much the same way, and are prettier. Just f.y.i.-- pertinax, Apr 13 2020 <Brief roar of flamethrower/>
Forget what, did you say ?-- 8th of 7, Apr 13 2020 You've set fire to your litmus paper again. Good thing no-one's been panic-buying it.-- pertinax, Apr 13 2020 Is that true about forget-me-nots? (I love that song, btw.)-- blissmiss, Apr 13 2020 Apparently, yes. As a child, I knew from literature that forget-me- nots were supposed to be blue, and wondered why some of ours were pink until I saw the neighbour's cat pissing on them. Then I confirmed the hypothesis using vinegar.-- pertinax, Apr 14 2020 Helpful for people with anosmia.-- nineteenthly, Apr 14 2020 <Sniffs charred fragments of forget-me-nots/>
"Smells like ... victory ..."
// confirmed the hypothesis using vinegar. //
Pouring vinegar on cats is always fun.-- 8th of 7, Apr 14 2020 random, halfbakery